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A P1G0 diabetic woman is at risk of delivering at 30 weeks gestation. Her obstetrician counsels her that there is a risk the baby could have significant pulmonary distress after it is born. However, she states she will administer a drug to the mother to help prevent this from occurring. By what action will this drug prevent respiratory distress in the premature infant?

Increasing the secretory product of type II alveolar cells

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B

A case-control study is conducted to investigate the association between the use of phenytoin during pregnancy in women with epilepsy and the risk for congenital malformations. The odds ratio of congenital malformations in newborns born to women who were undergoing treatment with phenytoin is 1.74 (P = 0.02) compared to newborns of women who were not treated with phenytoin. Which of the following 95% confidence intervals is most likely reported for this association?

1.34 to 2.36

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D

A 5-year-old boy presents with altered mental status and difficulty breathing for the past couple of hours. The patient’s father, a mechanic, says the boy accidentally ingested an unknown amount of radiator fluid. The patient’s vital signs are: temperature 37.1°C (98.8.F), pulse 116/min, blood pressure 98/78 mm Hg, and respiratory rate 42/min. On physical examination, cardiopulmonary auscultation reveals deep, rapid respirations with no wheezing, rhonchi, or crepitations. An ABG reveals the blood pH to be 7.2 with an anion gap of 16 mEq/L. Urinalysis reveals the presence of oxalate crystals. Which of the following is the most appropriate antidote for the poison that this patient has ingested?

Fomepizole

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D

A 45-year-old man with HIV comes to the physician because of multiple lesions on his chest and lower extremities. The lesions have progressively increased in size and are not painful or pruritic. Current medications include abacavir, dolutegravir, and lamivudine. A photograph of the lesions is shown. His CD4+ T-lymphocyte count is 450/mm3 (normal ≥ 500/mm3). A skin biopsy shows multiple spindle-shaped cells and lymphocytic infiltrate. Which of the following is the most appropriate pharmacotherapy?

Alpha-interferon

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C

An 18-year-old man presents to the office, complaining of an itchy patch on his torso that appeared one week ago. The patient is on the college wrestling team and is concerned he will not be able to compete if it gets infected. He has no significant medical history, and his vital signs are within normal limits. On examination, there is an erythematous, scaly plaque with central clearing at approximately the level of rib 6 on the left side of his torso. What diagnostic test would be most appropriate at this time?

KOH preparation

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D

A 65-year-old man with no significant medical history begins to have memory loss and personality changes. Rapidly, over the next few months his symptoms increase in severity. He experiences a rapid mental deterioration associated with sudden, jerking movements, particularly in response to being startled. He has gait disturbances as well. Eventually, he lapses into a coma and dies approximately ten months after the onset of symptoms. Which of the following would most likely be seen on autopsy of the brain in this patient?

C

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C

A 32-year-old woman with type 1 diabetes mellitus is brought to the emergency department by her husband because of a 2-day history of profound fatigue and generalized weakness. One week ago, she increased her basal insulin dose because of inadequate control of her glucose concentrations. Neurologic examination shows hyporeflexia. An ECG shows T-wave flattening and diffuse ST-segment depression. Which of the following changes are most likely to occur in this patient's kidneys?

Increased activity of H+/K+ antiporter in α-intercalated cells

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A

A newborn male is evaluated in the hospital nursery 24 hours after birth for cyanosis. The patient was born at 38 weeks gestation to a 36-year-old gravida 3 via cesarean section for fetal distress. The patient’s mother received inconsistent prenatal care, and the delivery was uncomplicated. The patient’s Apgar evaluation was notable for acrocyanosis at both 1 and 5 minutes of life. The patient’s mother denies any family history of congenital heart disease. The patient’s father has a past medical history of hypertension, and one of the patient’s older siblings was recently diagnosed with autism spectrum disorder. The patient’s birth weight was 3180 g (7 lb 0 oz). In the hospital nursery, his temperature is 99.3°F (37.4°C), blood pressure is 66/37 mmHg, pulse is 179/min, and respirations are 42/min. On physical exam, the patient is in moderate distress. He has low-set ears, orbital hypertelorism, and a cleft palate. The patient is centrally cyanotic. A chest CT shows thymic hypoplasia. Echocardiography demonstrates a single vessel emanating from both the right and left ventricle. This patient should be urgently evaluated for which of the following acute complications?

Neuromuscular irritability

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C

A 29-year-old woman comes to the physician because of intermittent episodes of sharp chest pain and palpitations. She appears nervous. Her pulse is 115/min and irregularly irregular, and blood pressure is 139/86 mmHg. Examination shows a fine tremor on both hands and digital swelling; the extremities are warm. There is retraction of the right upper eyelid. Which of the following is the most appropriate next step in the management of this patient?

Propranolol

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E

A 23-year-old female is found by her roommate in her dormitory. The patient has a history of Type 1 Diabetes Mellitus and was binge drinking the night prior with friends at a local bar. The patient is brought to the emergency department, where vital signs are as follow: T 97.3 F, HR 119 bpm, BP 110/68 mmHg, RR 24, SpO2 100% on RA. On physical exam, the patient is clammy to touch, mucous membranes are tacky, and she is generally drowsy and disoriented. Finger stick glucose is 342 mg/dL; additional lab work reveals: Na: 146 K: 5.6 Cl: 99 HCO3: 12 BUN: 18 Cr: 0.74. Arterial Blood Gas reveals: pH 7.26, PCO2 21, PO2 102. Which of the following statements is correct regarding this patient's electrolyte and acid/base status?

The patient has an anion gap metabolic acidosis with decreased total body potassium

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D

A 36-year-old man is admitted to the hospital because of a 1-day history of epigastric pain and vomiting. He has had similar episodes of epigastric pain in the past. He drinks 8 oz of vodka daily. Five days after admission, the patient develops aspiration pneumonia and sepsis. Despite appropriate therapy, the patient dies. At autopsy, the pancreas appears gray, enlarged, and nodular. Microscopic examination of the pancreas shows localized deposits of calcium. This finding is most similar to an adaptive change that can occur in which of the following conditions?

Congenital CMV infection

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D

A 37-year-old patient is being evaluated for involuntary movements, difficulty swallowing food, and personality change. He has entered a clinical trial that is studying the interaction of certain neuromediators in patients with similar (CAG) n trinucleotide repeat disorders. The laboratory results of 1 of the candidates for the clinical trial are presented below: Acetylcholine ↓ Dopamine ↑ Gamma-aminobutyric acid (GABA) ↓ Norepinephrine unchanged Serotonin unchanged Which trinucleotide disorder most likely represents the diagnosis of this patient?

Huntington's disease

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D

A 65-year-old man with hypertension comes to the physician for a routine health maintenance examination. Current medications include atenolol, lisinopril, and atorvastatin. His pulse is 86/min, respirations are 18/min, and blood pressure is 145/95 mm Hg. Cardiac examination is shown. Which of the following is the most likely cause of this physical examination finding?

Decreased compliance of the left ventricle

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A

A 55-year-old man presents to the hospital with chief complaints of unintentional weight loss, anorexia, fever, and sweating. The patient has pleuritic chest pain, progressive dyspnea, and dry cough. There is no history of orthopnea or paroxysmal nocturnal dyspnea. On examination, the patient is afebrile and pericardial friction rub is noted. ECG shows diffuse ST-segment elevation in V1-V4 along with T wave inversion. Chest X-ray and CT scan show anterior and inferior pericardial eggshell calcification. Echocardiography reveals thickened pericardium and signs of diastolic right ventricular collapse. Pericardial fluid is sent for Ziehl-Neelsen staining to detect acid-fast bacilli. Mycobacterium tuberculosis is detected by PCR. What is the most likely mechanism associated with the patient’s condition?

Dystrophic calcification

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B

A 7-month-old infant with Tetralogy of Fallot is brought to the emergency department by her parents because of a 1-day history of fever, cough, and difficulty breathing. She was born at 29 weeks of gestation. Her routine immunizations are up-to-date. She is currently in the 4th percentile for length and 2nd percentile for weight. She appears ill. Her temperature is 39.1°C (102.3°F). Physical examination shows diffuse wheezing, subcostal retractions, and bluish discoloration of the fingertips. Administration of which of the following would most likely have prevented this patient's current condition?

Palivizumab

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E

A 62-year-old woman has been receiving amoxicillin for acute sinusitis for 12 days. She develops a macular rash on her neck, back, and torso. The amoxicillin is therefore changed to cephalexin for an additional week. The rash resolves, but she returns complaining of fatigue, flank pain, and fever that has persisted despite the resolution of the sinusitis. She has a history of essential hypertension, hyperlipidemia, and gastric reflux. She has been on a stable regimen of lisinopril, simvastatin, and omeprazole. Today, her vital signs reveal: temperature 37.9°C (100.2°F), blood pressure 145/90 mm Hg, regular pulse 75/min, and respirations 16/min. The physical examination is unremarkable. Serum urea and creatinine are elevated. Urinalysis shows leukocyturia, but urine bacterial culture is negative. A urine cytospin stained with Hansel’s solution reveals 3% binucleated cells with eosinophilic, granular cytoplasm. Which of the following is the most likely diagnosis?

Acute interstitial nephritis

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A

A 61-year-old man with a history of stage IIIa lung adenocarcinoma that has been treated with wedge resection and chemotherapy presents to the primary care clinic. He is largely asymptomatic, but he demonstrates a persistent microcytic anemia despite iron supplementation. Colonoscopy performed 3 years earlier was unremarkable. His past medical history is significant for diabetes mellitus type II, hypertension, acute lymphoblastic leukemia as a child, and hypercholesterolemia. He currently smokes 1 pack of cigarettes per day, drinks a glass of pinot grigio per day, and currently denies any illicit drug use. His vital signs include: temperature, 36.7°C (98.0°F); blood pressure, 126/74 mm Hg; heart rate, 87/min; and respiratory rate, 17/min. On physical examination, his pulses are bounding, complexion is pale, but breath sounds remain clear. Oxygen saturation was initially 91% on room air, with a new oxygen requirement of 2 L by nasal cannula. Which of the following lab values would suggest anemia of chronic disease as the underlying etiology?

Decreased serum iron and transferrin, increased ferritin, normal serum transferrin receptor

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A

A 62-year-old woman presents to her physician with a painless breast mass on her left breast for the past 4 months. She mentions that she noticed the swelling suddenly one day and thought it would resolve by itself. Instead, it has been slowly increasing in size. On physical examination of the breasts, the physician notes a single non-tender, hard, and fixed nodule over left breast. An ultrasonogram of the breast shows a solid mass, and a fine-needle aspiration biopsy confirms the mass to be lobular carcinoma of the breast. When the patient asks about her prognosis, the physician says that the prognosis can be best determined after both grading and staging of the tumor. Based on the current diagnostic information, the physician says that they can only grade, but no stage, the neoplasm. Which of the following facts about the neoplasm is currently available to the physician?

The tumor cells exhibit marked nuclear atypia.

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A

A 67-year-old woman has fallen from the second story level of her home while hanging laundry. She was brought to the emergency department immediately and presented with severe abdominal pain. The patient is anxious, and her hands and feet feel very cold to the touch. There is no evidence of bone fractures, superficial skin wounds, or a foreign body penetration. Her blood pressure is 102/67 mm Hg, respirations are 19/min, pulse is 87/min, and temperature is 36.7°C (98.0°F). Her abdominal exam reveals rigidity and severe tenderness. A Foley catheter and nasogastric tube are inserted. The central venous pressure (CVP) is 5 cm H2O. The medical history is significant for hypertension. Which of the following is best indicated for the evaluation of this patient?

Ultrasound

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B

A 74-year-old female is brought to the emergency department because of a 2-week history of increasing weakness and chills. She also notes difficulty breathing for the last three days. Eight weeks ago, she underwent left hemicolectomy for adenocarcinoma of the colon. She subsequently developed a severe urinary tract infection, was treated in the intensive care unit for four days, and was discharged from the hospital three weeks ago. She has type 2 diabetes mellitus, osteoporosis with lumbar pain, hypertension, and atrial fibrillation. She has smoked one pack of cigarettes daily for 50 years. She does not drink alcohol and has never used illicit drugs. Current medications include warfarin, metformin, lisinopril, and aspirin. She appears lethargic and has a large conjunctival hemorrhage in her left eye. Her temperature is 39.3°C (102.7°F), pulse is 112/min, respirations are 25/min, and blood pressure is 126/79 mm Hg. Cardiac auscultation reveals a new holosystolic murmur over the apex. Abdominal examination shows mild, diffuse tenderness throughout the upper quadrants and a well-healed 12-cm paramedian scar. There are multiple tender nodules on the palmar surface of her fingertips. Funduscopic examination shows retinal hemorrhages with pale centers. An ECG shows atrial fibrillation and right bundle branch block. Which of the following is the most likely underlying etiology of this patient's condition?

Enterococcus faecalis infection

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E

A 61-year-old woman presents to her physician with a persistent cough. She has been unable to control her cough and also is finding it increasingly difficult to breathe. The cough has been persistent for about 2 months now, but 2 weeks ago she started noticing streaks of blood in the sputum regularly after coughing. Over the course of 4 months, she has also observed an unusual loss of 10 kg (22 lb) in her weight. She has an unchanged appetite and remains fairly active, which makes her suspicious as to the cause of her weight loss. Another troublesome concern for her is that on a couple occasions over the past few weeks, she has observed herself drenched in sweat when she wakes up in the morning. Other than having a 35 pack-year smoking history, her medical history is insignificant. She is sent for a chest X-ray which shows a central nodule of about 13 mm located in the hilar region. Which of the following would be the next best step in the management of this patient?

Mediastinoscopy

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B

A 2-year-old boy is brought to the emergency department by his parents after they found him to be lethargic and febrile. His current symptoms started 1 week ago and initially consisted of a sore throat and a runny nose. He subsequently developed a fever and productive cough that has become worse over time. Notably, this patient has previously presented with pneumonia and gastroenteritis 8 times since he was born. On presentation, the patient's temperature is 103°F (39.4°C), blood pressure is 90/50 mmHg, pulse is 152/min, and respirations are 38/min. Based on clinical suspicion, an antibody panel is obtained and the results show low levels of IgG and IgA relative to the level of IgM. The expression of which of the following genes is most likely abnormal in this patient?

CD40L

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A

A 71-year-old man comes to the emergency department because of a 2-month history of severe muscle cramps and back pain. He says that he is homeless and has not visited a physician in the past 20 years. He is 183 cm (6 ft 0 in) tall and weighs 62 kg (137 lb); BMI is 18.5 kg/m2. His blood pressure is 154/88 mm Hg. Physical examination shows pallor, multiple cutaneous excoriations, and decreased sensation over the lower extremities. Serum studies show: Calcium 7.2 mg/dL Phosphorus 5.1 mg/dL Glucose 221 mg/dL Creatinine 4.5 mg/dL An x-ray of the spine shows alternating sclerotic and radiolucent bands in the lumbar and thoracic vertebral bodies. Which of the following is the most likely explanation for these findings?"

Secondary hyperparathyroidism

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B

A 23-year-old woman presents to her primary care physician for knee pain. The patient states it started yesterday and has been steadily worsening. She recently joined a volleyball team to try to get into shape as she was informed that weight loss would be beneficial for her at her last physical exam. She states that she has been repetitively pivoting and twisting on her knee while playing volleyball. The patient has a past medical history of polycystic ovarian syndrome and is currently taking oral contraceptive pills. Her temperature is 98.5°F (36.9°C), blood pressure is 137/88 mmHg, pulse is 90/min, respirations are 12/min, and oxygen saturation is 98% on room air. Physical exam reveals an obese woman with facial hair. Physical exam is notable for tenderness that is mediated with palpation over the medial aspect of the tibia just inferior to the patella. Her BMI is 37 kg/m^2. The rest of the exam of the lower extremity is not remarkable. Which of the following is the most likely diagnosis?

Pes anserine bursitis

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E

A 47-year-old woman comes to the physician because of a 6-week history of fatigue and low-grade fever. She has no history of serious illness except for a bicuspid aortic valve, diagnosed 10 years ago. She does not use illicit drugs. Her temperature is 37.7°C (99.9°F). Physical examination shows petechiae under the fingernails and multiple tender, red nodules on the fingers. A new grade 2/6 diastolic murmur is heard at the right second intercostal space. Which of the following is the most likely causal organism?

Streptococcus sanguinis

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D

A 22-year-old man is rushed to the emergency department after a motor vehicle accident. The patient states that he feels weakness and numbness in both of his legs. He also reports pain in his lower back. His airway, breathing, and circulation is intact, and he is conversational. Neurologic exam is significant for bilateral lower extremity flaccid paralysis and impaired pain and temperature sensation up to T10-T11 with normal vibration sense. A computerized tomography scan of the spine is performed which shows a vertebral burst fracture of the vertebral body at the level of T11. Which of the following findings is most likely present in this patient?

Preserved fine touch

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B

A 58-year-old obese woman presents with painless postmenopausal bleeding for the past 5 days. A recent endometrial biopsy confirmed endometrial cancer, and the patient is scheduled for total abdominal hysterectomy and bilateral salpingo-oophorectomy. Past medical history is significant for stress incontinence and diabetes mellitus type 2. Menarche was at age 11 and menopause was at age 55. The patient has 4 healthy children from uncomplicated pregnancies, who were all formula fed. Current medications are topical estrogen and metformin. Family history is significant for breast cancer in her grandmother at age 80. Which of the following aspects of this patient’s history is associated with a decreased risk of breast cancer?

Multiple pregnancies

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E

A middle-aged homeless man is found lying unresponsive on the streets by the police and is rushed to the emergency department. His vital signs include: blood pressure 110/80 mm Hg, pulse rate 100/min, and respirations 10/min and shallow. On physical examination, his extremities are cold and clammy. Pupils are constricted and non-reactive. His blood glucose is 55 mg/dL. IV access is established immediately with the administration of dextrose and naloxone. In half an hour, the patient is fully conscious, alert and responsive. He denies any medical illnesses, hospitalizations, or surgeries in the past. Physical examination reveals injection track marks along both arms. He admits to the use of cocaine and heroin. He smokes cigarettes and consumes alcohol. His vital signs are now stable. A urine sample is sent for toxicology screening. Which of the following was the most likely cause of this patient’s respiratory depression?

Opioid intoxication

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E

A 47-year-old female with a history of hypertension presents to your outpatient clinic for numbness, tingling in her right hand that has been slowly worsening over the last several months. She has tried using a splint but receives minimal relief. She is an analyst for a large consulting firm and spends most of her workday in front of a computer. Upon examination, you noticed that the patient has a prominent jaw and her hands appear disproportionately large. Her temperature is 99 deg F (37.2 deg C), blood pressure is 154/72 mmHg, pulse is 87/min, respirations are 12/min. A fasting basic metabolic panel shows: Na: 138 mEq/L, K: 4.1 mEq/L, Cl: 103 mEq/L, CO2: 24 mEq/L, BUN: 12 mg/dL, Cr: 0.8 mg/dL, Glucose: 163 mg/dL. Which of the following tests would be most helpful in identifying the underlying diagnosis?

Measurement of insulin-like growth factor 1 alone and growth hormone levels after oral glucose

step2&3

B

A 17-year-old woman is rushed into the emergency department by her father who found her collapsed in her bedroom 15 minutes before the ambulance's arrival. There was an empty bottle of clomipramine in her bedroom which her mother takes for her depression. Vital signs include the following: respiratory rate 8/min, pulse 130/min, and blood pressure 100/60 mm Hg. On physical examination, the patient is unresponsive to vocal and tactile stimuli. Oral mucosa and tongue are dry, and the bladder is palpable. A bedside electrocardiogram (ECG) shows widening of the QRS complexes. Which of the following would be the best course of treatment in this patient?

Sodium bicarbonate

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A

A 3-year-old girl is brought to the physician by her 30-year-old mother, who reports that her daughter has been passing multiple foul-smelling, bulky stools with flatulence every day for the last 6 months. The girl was born in Guatemala, and soon after her birth, her parents moved to the United States so that they could access better healthcare. During pregnancy, the mother had little prenatal care, but labor and delivery were uneventful. However, the newborn had significant abdominal distention immediately at birth that increased when she ate or yawned. She failed to pass stool in the first 24 hours of life and had greenish-black vomitus. The parents report similar symptoms in other family members. After diagnosis, the girl underwent a procedure that alleviated her symptoms; however, there was no remission. Her abdominal X-ray (see the first image) and barium contrast enema (second image) from when she was born is shown. Her blood pressure is 100/68 mm Hg, heart rate is 96/min, respiratory rate is 19/min, and temperature is 36.7°C (98.0°F). The girl is in the 10th percentile for height and weight. On physical exam, she has periumbilical and midepigastric tenderness to palpation without rebound tenderness or guarding. There is a slight genu varum deformity and bony tenderness noted in her legs. She has foul-smelling flatulation 2–3 times during the visit. Her rectosphincteric reflex is intact. She has decreased fecal elastase and a negative D-xylose test. Which of the following is the most appropriate long-term treatment for her condition?

Enzyme-replacement therapy

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A

A 60-year-old, multiparous, woman comes to the physician because of urinary leakage for the past 4 months. She involuntarily loses a small amount of urine after experiencing a sudden, painful sensation in the bladder. She wakes up at night several times to urinate, and she sometimes cannot make it to the bathroom in time. She has diabetes mellitus type 2 controlled with insulin and a history of pelvic organ prolapse, for which she underwent surgical treatment 5 years ago. Menopause was 11 years ago. She drinks 4-5 cups of coffee daily. Pelvic examination shows no abnormalities, and a Q-tip test is negative. Ultrasound of the bladder shows a normal postvoid residual urine. Which of the following is the underlying cause of this patient's urinary incontinence?

Increased detrusor muscle activity

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C

A 35-year-old woman with type 1 diabetes mellitus comes to the emergency department for evaluation of a 1-month history of fever, fatigue, loss of appetite, and a 3.6-kg (8-lb) weight loss. She has also had a cough for the last 2 months. She reports recent loss of pubic hair. The patient immigrated from the Philippines 7 weeks ago. Her mother has systemic lupus erythematosus. She has never smoked and does not drink alcohol. Her only medication is insulin, but she sometimes misses doses. She is 165 cm (5 ft 5 in) tall and weighs 49 kg (108 lb); BMI is 18 kg/m2. She appears lethargic. Her temperature is 38.9°C (102°F), pulse is 58/min, and blood pressure is 90/60 mm Hg. Examination shows decreased sensation to touch and vibration over both feet. The remainder of the examination shows no abnormalities. Serum studies show: Na+ 122 mEq/L Cl- 100 mEq/L K+ 5.8 mEq/L Glucose 172 mg/dL Albumin 2.8 g/dL Cortisol 2.5 μg/dL ACTH 531.2 pg/mL (N=5–27 pg/mL) CT scan of the abdomen with contrast shows bilateral adrenal enlargement. Which of the following is the most likely underlying mechanism of this patient's symptoms?"

Infection with acid-fast bacilli

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D

A 53-year-old man is brought to the emergency department following an episode of loss of consciousness 1 hour ago. He had just finished micturating, when he fell down. His wife heard the noise and found him unconscious on the floor. He regained consciousness after 30 seconds and was able to talk normally with his wife immediately. There was no urinary incontinence. On arrival, he is alert and oriented. Cardiopulmonary examination shows no abnormalities. Neurologic examination shows no focal findings. Serum concentrations of glucose, creatinine, and electrolytes are within the reference range. An electrocardiogram shows no abnormalities. Which of the following is the most likely diagnosis?

Situational syncope

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B

A 3000-g (6.6-lb) female newborn is delivered at term to a 23-year-old primigravid woman. The mother has had no prenatal care. Immunization records are not available. Cardiac examination shows a continuous heart murmur. There are several bluish macules on the skin that do not blanch with pressure. Slit lamp examination shows cloudy lenses in both eyes. The newborn does not pass his auditory screening tests. Which of the following is the most likely diagnosis?

Congenital rubella infection

step1

C

A group of investigators conducted a randomized controlled trial to compare the effectiveness of rivaroxaban to warfarin for ischemic stroke prevention in patients with atrial fibrillation. A total of 14,000 participants were enrolled and one half was assigned to each of the cohorts. The patients were followed prospectively for 3 years. At the conclusion of the trial, the incidence of ischemic stroke in participants taking rivaroxaban was 1.7% compared to 2.2% in participants taking warfarin. The hazard ratio is calculated as 0.79 and the 95% confidence interval is reported as 0.64 to 0.97. If the study was conducted with a total of 7,000 participants, which of the following changes would most be expected?

Increased confidence interval range

step1

C

A 48-year-old woman comes to the physician for the evaluation of a left breast mass that she noticed 4 weeks ago. It has rapidly increased in size during this period. Vital signs are within normal limits. Examination shows large dense breasts; a 6-cm, nontender, multinodular mass is palpated in the upper outer quadrant of the left breast. There are no changes in the skin or nipple. There is no palpable cervical or axillary adenopathy. Mammography shows a smooth polylobulated mass. An image of a biopsy specimen is shown. Which of the following is the most likely diagnosis?

Phyllodes tumor

step1

D

An investigator is studying obesity in mice. Over the course of 2 weeks, mice in the experimental group receive a daily injection with a synthetic analog of an endogenous hormone. Compared to the control group, the hormone-injected mice eat more and gain significantly more weight. Which of the following is the most likely explanation for the observed weight gain in the experimental group?

Ghrelin stimulation of the lateral hypothalamus

step1

D

A 52-year-old man presents to the emergency department because of pain and swelling in his left leg over the past few hours. He traveled from Sydney to Los Angeles 2 days ago. He has had type 2 diabetes mellitus for 10 years and takes metformin for it. He has smoked a pack of cigarettes daily for 25 years. His temperature is 36.9°C (98.4°F), the blood pressure is 140/90 mm Hg, and the pulse is 90/min. On examination, the left calf is 5 cm greater in circumference than the right. The left leg appears more erythematous than the right with dilated superficial veins. Venous duplex ultrasound shows non-compressibility. Which of the following best represents the mechanism of this patient’s illness?

Impaired venous blood flow

step2&3

B

A man returns home late at night to find his 15-year-old son and 40-year-old wife unconscious in the family room. He immediately summons emergency services. In the field, pulse oximetry shows oxygen saturation at 100% for both patients. 100% yet they both appear cyanotic. Both patients are provided with 2L of oxygen by way of nasal cannula on the way to the hospital. An arterial blood gas is performed on the teenager and reveals pH of 7.35, PaCO2 of 31.8 mm Hg, PaO2 of 150 mm Hg, HCO3- of 20 mEq/L, SaO2 of 80%, and a COHb of 18%. What is the most likely cause of his condition?

Carbon monoxide poisoning

step1

D

A 28-year-old research assistant is brought to the emergency department for severe chemical burns 30 minutes after accidentally spilling hydrochloric acid on himself. The burns cover both hands and forearms. His temperature is 37°C (98.6°F), pulse is 112/min, respirations are 20/min, and blood pressure is 108/82 mm Hg. Initial stabilization and resuscitation is begun, including respiratory support, fluid resuscitation, and cardiovascular stabilization. The burned skin is irrigated with saline water to remove the chemical agent. Which of the following is the most appropriate method to verify adequate fluid infusion in this patient?

Urinary output "

step2&3

E

A 61-year-old female with congestive heart failure and type 2 diabetes is brought to the emergency room by her husband because of an altered mental status. He states he normally helps her be compliant with her medications, but he had been away for several days. On physical exam, her temperature is 37.2 C, BP 85/55, and HR 130. Serum glucose is 500 mg/dL. Which of the following is the first step in the management of this patient?

IV NS

step2&3

B

A 27-year-old G2P2002 is recovering in the hospital on postpartum day 3 after a low transverse C-section. During morning rounds, she reports a “pus-like” discharge and shaking chills overnight. She also endorses increased uterine cramping compared to the day before, but her postpartum course has otherwise been uneventful with a well-healing incision and normal vaginal bleeding. The patient’s prenatal care was complicated by HIV with a recent viral load of 400 copies/mL, type I diabetes well controlled on insulin, and a history of herpes simplex virus encephalitis in her first child. She did not have any genital lesions during the most recent pregnancy. Four days ago, she presented to the obstetric triage unit after spontaneous rupture of membranes and onset of labor. She made slow cervical change and reached full dilation after 16 hours, but there was limited fetal descent. Cephalopelvic disproportion was felt to be the reason for arrest of descent, so prophylactic ampillicin was administered and C-section was performed. A vaginal hand was required to dislodge the fetus’s head from the pelvis, and a healthy baby boy was delivered. On postpartum day 3, her temperature is 101.5°F (38.6°C), blood pressure is 119/82 mmHg, pulse is 100/min, and respirations are 14/min. Her incision looks clean and dry, there is mild suprapubic tenderness, and a foul yellow discharge tinged with blood is seen on her pad. Which of the following is the most significant risk factor for this patient’s presentation?

C-section after onset of labor

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C

A 34-year-old man comes to the physician because of fatigue and shortness of breath with moderate exertion for the past 2 months. Over the past 10 days, he has had low-grade fevers and night sweats. He has no history of serious illness except for a bicuspid aortic valve diagnosed 5 years ago. He has smoked one pack of cigarettes daily for 10 years and drinks 3–5 beers on social occasions. He does not use illicit drugs. The patient takes no medications. He appears weak. His temperature is 37.7°C (99.9°F), pulse is 70/min, and blood pressure is 128/64 mm Hg. The lungs are clear to auscultation. A grade 2/6 systolic murmur is heard best at the right sternal border and second intercostal space. There are several hemorrhages underneath his fingernails on both hands and multiple tender, red nodules on his fingers. Which of the following is the most likely causal organism?

Streptococcus sanguinis

step2&3

B

A 24-year-old man presents to the emergency department after a motor vehicle collision. He was the front seat and unrestrained driver in a head on collision. His temperature is 99.2°F (37.3°C), blood pressure is 90/65 mmHg, pulse is 152/min, respirations are 16/min, and oxygen saturation is 100% on room air. Physical exam is notable for a young man who opens his eyes spontaneously and is looking around. He answers questions with inappropriate responses but discernible words. He withdraws from pain but does not have purposeful movement. Which of the following is this patient’s Glasgow coma scale?

11

step2&3

C

A 34-year-old Caucasian female presents at the ER with fever and sharp pain in her chest upon coughing and inhalation. Three weeks earlier she presented to her rheumatologist with a butterfly rash, joint pain and fatigue and was given a diagnosis of systemic lupus erythematosus. A friction rub is present upon physical exam. Which of the following do you most suspect in this patient?

Pericarditis

step1

D

A 47-year-old man with a history of alcoholism undergoes an upper endoscopy, which reveals a superficial mucosal tear in the distal esophagus. Laboratory results show a metabolic alkalosis. What is the most likely mechanism of the acid/base disturbance in this patient?

Vomiting

step1

C

A 60-year-old man comes to the physician because of flank pain, rash, and blood-tinged urine for 1 day. Two months ago, he was started on hydrochlorothiazide for hypertension. He takes acetaminophen for back pain. Examination shows a generalized, diffuse maculopapular rash. Serum studies show a creatinine concentration of 3.0 mg/dL. Renal ultrasonography shows no abnormalities. Which of the following findings is most likely to be observed in this patient?

Urinary eosinophils

step1

E

Nucleic acid amplification testing (NAAT) of first-void urine confirms infection with Chlamydia trachomatis. Treatment with the appropriate pharmacotherapy is started. Which of the following health maintenance recommendations is most appropriate at this time?

Avoid sun exposure

step2&3

A

A 14-year-old boy presents as a new patient to your practice. While conducting your physical exam, you observe the findings depicted in Figures A and B. Which of the following additional findings would most likely be found in this patient?

Iris hamartomas

step1

D

An investigator who studies virology obtains a biopsy from the ulcer base of an active genital herpes lesion for viral culture. The cultured virions, along with herpes simplex virions of a different phenotype, are cointroduced into a human epithelial cell in vitro. The progeny viruses are found to have phenotypes that are distinct from the parent strains. Sequencing of these progeny viruses shows that most genomes have material from both parent strains. These findings are best explained by which of the following terms?

Recombination

step1

B

A 22-year-old man is rushed to the emergency room with constant, severe right lower abdominal pain that started 7 hours ago in the periumbilical region and later shifted to the right lower quadrant with a gradual increase in intensity. The patient’s blood pressure is 110/80 mm Hg, the heart rate is 76/min, the respiratory rate is 17/min, and the temperature is 37.5℃ (99.5℉). The physical examination shows tenderness, muscle guarding, and rebound over the right lower quadrant of the abdomen. Abdominal sonography shows a dilated appendix with a periappendiceal fluid collection. He is diagnosed with acute appendicitis and undergoes a laparoscopic appendectomy. The histopathologic examination of the removed appendix is shown in the image. Which of the following substances is responsible for attracting the marked cells to the inflamed tissue?

IL-8

step1

B

A 65-year-old man presents to his primary care physician for a pre-operative evaluation. He is scheduled for cataract surgery in 3 weeks. His past medical history is notable for diabetes, hypertension, and severe osteoarthritis of the right knee. His medications include metformin, hydrochlorothiazide, lisinopril, and aspirin. His surgeon ordered blood work 1 month ago, which showed a hemoglobin of 14.2 g/dL, INR of 1.2, and an hemoglobin A1c of 6.9%. His vital signs at the time of the visit show BP: 130/70 mmHg, Pulse: 80, RR: 12, and T: 37.2 C. He has no current complaints and is eager for his surgery. Which of the following is the most appropriate course of action for this patient at this time?

Medically clear the patient for surgery

step2&3

A

A 19-year-old African female refugee has been granted asylum in Stockholm, Sweden and has been living there for the past month. She arrived in Sweden with her 2-month-old infant, whom she exclusively breast feeds. Which of the following deficiencies is the infant most likely to develop?

Vitamin D

step1

C

A 10-year-old girl is brought to the emergency department by her mother 30 minutes after having had a seizure. When her mother woke her up that morning, the girl's entire body stiffened and she started shaking vigorously for several minutes. Her mother also reports that over the past few months, her daughter has had multiple episodes of being unresponsive for less than a minute, during which her eyelids were fluttering. The girl did not recall these episodes afterwards. Upon arrival, she appears drowsy. Neurologic examination shows no abnormalities. Which of the following is the most appropriate pharmacotherapy to prevent recurrence of this patient's symptoms?

Valproate

step1

E

A 48-year-old female complains of tingling sensation in her fingertips as well as the skin around her mouth which woke her up from sleep. She is in the postoperative floor as she just underwent a complete thyroidectomy for papillary thyroid cancer. Her temperature is 37° C (98.6° F), respirations are 15/min, pulse is 67/min, and blood pressure is 122/88 mm Hg. While recording the blood pressure, spasm of the muscles of the hand and forearm is seen. What is the next best step in the management of this patient?

Calcium replacement

step2&3

E

A 23-year old man is brought to the emergency department by his brother after trying to jump out of a moving car. He says that the Federal Bureau of Investigation has been following him for the last 7 months. He recently quit his job at a local consulting firm to work on his mission to rid the world from evil. He does not smoke, drink alcoholic beverages, or use illicit drugs. He takes no medications. His temperature is 36.7°C (98.1°F), pulse is 90/min, respirations are 20/min, and blood pressure is 120/86 mm Hg. On mental status examination, his response to the first question lasted 5 minutes without interruption. He switched topics a number of times and his speech was pressured. He spoke excessively about his plan to “bring absolute justice to the world”. He has a labile affect. There is no evidence of suicidal ideation. A toxicology screen is negative. He is admitted to the hospital for his symptoms and starts therapy. One week later, he develops difficulty walking and a tremor that improves with activity. Which of the following is the most likely cause of this patient's latest symptoms?

Dopamine antagonist

step2&3

A

A 10-year-old boy is referred to a pediatric neurologist by his pediatrician for lower extremity weakness. The boy is healthy with no past medical history, but his parents began to notice that he was having difficulty at football practice the previous day. Over the course of the past 24 hours, the boy has become increasingly clumsy and has been “tripping over himself.” On further questioning, the boy had a viral illness the previous week and was out of school for 2 days. Today, the patient’s temperature is 99.3°F (37.4°C), blood pressure is 108/72 mmHg, pulse is 88/min, respirations are 12/min. On motor exam, the patient has 5/5 strength in hip flexion, 5/5 strength in knee extension and flexion, 3/5 strength in foot dorsiflexion, and 5/5 strength in foot plantarflexion. The findings are the same bilaterally. On gait exam, the patient exhibits foot drop in both feet. Which of the following areas would the patient most likely have diminished sensation?

First dorsal webspace of foot

step1

B

A 35-year-old woman comes to the physician because of a 1-day history of swelling and pain in the left leg. Two days ago, she returned from a business trip on a long-distance flight. She has alcohol use disorder. Physical examination shows a tender, swollen, and warm left calf. Serum studies show an increased homocysteine concentration and a methylmalonic acid concentration within the reference range. Further evaluation of this patient is most likely to show which of the following serum findings?

Decreased folate concentration

step1

E

A 28-year-old woman comes to the emergency department because of increasing abdominal pain for 2 days. The pain is diffuse and constant, and she describes it as 7 out of 10 in intensity. She has also had numbness in her lower extremities for 12 hours. She has type 1 diabetes mellitus, migraine with aura, and essential tremor. She appears uncomfortable. She is oriented to place and person only. Her temperature is 37°C (98.6°F), pulse is 123/min, and blood pressure is 140/70 mm Hg. Examination shows a distended abdomen with no tenderness to palpation. Bowel sounds are decreased. Muscle strength and sensation is decreased in the lower extremities. There is a tremor of the right upper extremity. Urinalysis shows elevated levels of aminolevulinic acid and porphobilinogen. Which of the following is the most likely cause of this patient's symptoms?

Primidone

step2&3

A

One week after undergoing sigmoidectomy with end colostomy for complicated diverticulitis, a 67-year-old man has upper abdominal pain. During the surgery, he was transfused two units of packed red blood cells. His postoperative course was uncomplicated. Two days ago, he developed fever. He is currently receiving parenteral nutrition through a central venous catheter. He has type 2 diabetes mellitus, hypertension, and hypercholesterolemia. He is oriented to person, but not to place and time. Prior to admission, his medications included metformin, valsartan, aspirin, and atorvastatin. His temperature is 38.9°C (102.0°F), pulse is 120/min, and blood pressure is 100/60 mmHg. Examination shows jaundice of the conjunctivae. Abdominal examination shows tenderness to palpation in the right upper quadrant. There is no rebound tenderness or guarding; bowel sounds are hypoactive. Laboratory studies show: Leukocytes 13,500 /mm3 Segmented neutrophils 75 % Serum Aspartate aminotransferase 140 IU/L Alanine aminotransferase 85 IU/L Alkaline phosphatase 150 IU/L Bilirubin Total 2.1 mg/dL Direct 1.3 mg/dL Amylase 20 IU/L Which of the following is the most likely diagnosis in this patient?"

Acalculous cholecystitis

step2&3

A

An 82-year-old comes to the physician for a routine checkup. He feels well. He has a history of hypertension, peripheral vascular disease, carotid stenosis, and mild dementia. His father had Parkinson's disease and died of a stroke at the age of 74 years. He has smoked one-half pack of cigarettes daily for 30 years but quit at the age of 50 years. He drinks alcohol in moderation. Current medications include aspirin and lisinopril. He appears healthy. His temperature is 36.9°C (98.4°F), pulse is 73/min, respirations are 12/min, and blood pressure is 142/92 mmHg. Examination shows decreased pedal pulses bilaterally. Ankle jerk and patellar reflexes are absent bilaterally. Sensation to light touch, pinprick, and proprioception is intact bilaterally. Muscle strength is 5/5 bilaterally. He describes the town he grew up in with detail but only recalls one of three words after 5 minutes. Which of the following is the most appropriate next step in management for these findings?

No further workup required

step2&3

A

A 28-year-old woman with a history of intravenous drug use is brought to the emergency department because of a 1-day history of fatigue, yellow eyes, confusion, and blood in her stools. She appears ill. Her temperature is 38.1°C (100.6°F). Physical examination shows pain in the right upper quadrant, diffuse jaundice with scleral icterus, and bright red blood in the rectal vault. Further evaluation demonstrates virions in her blood, some of which have a partially double-stranded DNA genome while others have a single-stranded RNA genome. They are found to share an identical lipoprotein envelope. This patient is most likely infected with which of the following pathogens?

Deltavirus

step1

E

A 45-year-old woman comes to the physician because of a 2-week history of fatigue and excessive thirst. During this period, she has not been able to sleep through the night because of the frequent urge to urinate. She also urinates more than usual during the day. She drinks 4–5 liters of water and 1–2 beers daily. She has autosomal dominant polycystic kidney disease, hypertension treated with lisinopril, and bipolar disorder. Therapy with valproic acid was begun after a manic episode 3 months ago. Vital signs are within normal limits. Irregular flank masses are palpated bilaterally. The remainder of the examination shows no abnormalities. Laboratory studies show: Serum Na+ 152 mEq/L K+ 4.1 mEq/L Cl− 100 mEq/L HCO3− 25 mEq/L Creatinine 1.8 mg/dL Osmolality 312 mOsmol/kg Glucose 98 mg/dL Urine osmolality 190 mOsmol/kg The urine osmolality does not change after 3 hours despite no fluid intake or after administration of desmopressin. Which of the following is the most appropriate next step in management?"

Hydrochlorothiazide therapy

step2&3

D

A 54-year-old G2P2 presents to her gynecologist's office with complaints of frequent hot flashes, malaise, insomnia, and mild mood swings for 2 weeks. She has also noticed some pain with intercourse and vaginal dryness during this time. She is otherwise healthy besides hyperlipidemia, controlled on atorvastatin. She has no other past medical history, but underwent hysterectomy for postpartum hemorrhage. She is desiring of a medication to control her symptoms. Which of the following is the most appropriate short-term medical therapy in this patient for symptomatic relief?

Hormonal replacement therapy with estrogen alone

step2&3

A

A 28-year-old man is brought to the physician by his wife because she is worried about his unusual behavior. Two weeks ago, he was promoted and is now convinced that he will soon take over the firm. He has been working overtime at the office and spends most of his nights at parties. Whenever he comes home, he asks his wife to have sex with him and rarely sleeps more than 3 hours. He has a history of a similar episode and several periods of depression over the past 2 years. He currently takes no medications. He appears impatient, repeatedly jumps up from his seat, and says, “I have more important things to do.” There is no evidence of suicidal ideation. Urine toxicology screening is negative. Long-term treatment with lithium is started. Which of the following parameters should be regularly assessed in this patient while he is undergoing treatment?

Serum thyroid-stimulating hormone

step1

A

A 58-year-old man presents to the emergency department for evaluation of intermittent chest pain over the past 6 months. His history reveals that he has had moderate exertional dyspnea and 2 episodes of syncope while working at his factory job. These episodes of syncope were witnessed by others and lasted roughly 30 seconds. The patient states that he did not have any seizure activity. His vital signs include: blood pressure 121/89 mm Hg, heart rate 89/min, temperature 37.0°C (98.6°F), and respiratory rate 16/min. Physical examination reveals a crescendo-decrescendo systolic murmur in the right second intercostal area. An electrocardiogram is performed, which shows left ventricular hypertrophy. Which of the following is the best next step for this patient?

Transthoracic echocardiography

step2&3

E

A 42-year-old male presents to the emergency department due to severe headaches and palpitations. He has had previous episodes of sweating and headache, but this episode was particularly disabling. Upon presentation, he appears pale and diaphoretic. His temperature is 99.3°F (37.4°C), blood pressure is 162/118 mmHg, pulse is 87/min, and respirations are 20/min. Based on clinical suspicion, an abdominal CT scan is obtained, which shows a retroperitoneal mass. This patient's increased heart rate is most likely due to a change in activity of which of the following channels?

Hyperpolarization-activated, nucleotide-gated channels

step1

A

A 24-year-old woman presents to the labor and delivery floor in active labor at 40 weeks gestation. She has a prolonged course but ultimately vaginally delivers an 11 pound boy. On post operative day 2, she is noted to have uterine tenderness and decreased bowel sounds. She states she has been urinating more frequently as well. Her temperature is 102°F (38.9°C), blood pressure is 118/78 mmHg, pulse is 111/min, respirations are 17/min, and oxygen saturation is 98% on room air. Physical exam is notable for a non-distended abdomen and a tender uterus. Pulmonary exam reveals minor bibasilar crackles. Initial laboratory studies and a urinalysis are pending. Which of the following is the most likely diagnosis?

Endometritis

step2&3

D

A 52-year-old farmer presents to his physician with a puncture wound on his left shin. He got this wound accidentally when he felt unwell and went out to his garden "to catch some air". He reports he had been treated for tetanus 35 years ago and has received the Tdap vaccine several times since then, but he does not remember when he last received the vaccine. His vital signs are as follows: the blood pressure is 110/80 mm Hg, heart rate is 91/min, respiratory rate is 19/min, and temperature is 37.8°C (100.0°F). On physical examination, he is mildly dyspneic and pale. Lung auscultation reveals diminished vesicular breath sounds in the lower lobes bilaterally with a few inspiratory crackles heard over the left lower lobe. There is a puncture wound 1 cm in diameter that is contaminated with soil in the middle third of the patient’s shin. You order blood tests and an X-ray, and now you are arranging his wound treatment. How should tetanus post-exposure prevention be performed in this case?

The patient should receive both tetanus toxoid-containing vaccine and human tetanus immunoglobulin.

step1

D

A 74-year-old woman is brought to the physician by her husband because of difficulty sleeping for several years. She says that she has been gradually sleeping less each night over the past 2 years. It takes her 20–25 minutes to fall asleep each night and she wakes up earlier in the morning than she used to. On average, she sleeps 5–6 hours each night. She says that she has also been waking up several times per night and needs about 20 minutes before she is able to fall back to sleep. She feels mildly tired in the afternoon but does not take any naps. Her husband reports that she does not snore. The patient drinks two cups of coffee each morning, but she does not smoke or drink alcohol. She takes a 45 minute walk with her husband and their dog every other day. She is 160 cm (5 ft 3 in) tall and weighs 55 kg (121 lb); BMI is 21 kg/m2. Vital signs are within normal limits. On mental status examination, she appears cooperative with a mildly anxious mood and a full range of affect. Which of the following is the most appropriate next step in management?

Reassurance

step2&3

C

A 63-year-old man comes to the emergency department because of pain in his left groin for the past hour. The pain began soon after he returned from a walk. He describes it as 8 out of 10 in intensity and vomited once on the way to the hospital. He has had a swelling of the left groin for the past 2 months. He has chronic obstructive pulmonary disease and hypertension. Current medications include amlodipine, albuterol inhaler, and a salmeterol-fluticasone inhaler. He appears uncomfortable. His temperature is 37.4°C (99.3°F), pulse is 101/min, and blood pressure is 126/84 mm Hg. Examination shows a tender bulge on the left side above the inguinal ligament that extends into the left scrotum; lying down or applying external force does not reduce the swelling. Coughing does not make the swelling bulge further. There is no erythema. The abdomen is distended. Bowel sounds are hyperactive. Scattered rhonchi are heard throughout both lung fields. Which of the following is the most appropriate next step in management?

Open surgical repair

step2&3

C

Certain glucose transporters that are expressed predominantly on skeletal muscle cells and adipocytes are unique compared to those transporters found on other cell types within the body. Without directly affecting glucose transport in other cell types, which of the following would be most likely to selectively increase glucose uptake in skeletal muscle cells and adipocytes?

Increased levels of circulating insulin

step1

A

A 12-year-old boy presents to your office with facial swelling and dark urine. He has no other complaints other than a sore throat 3 weeks ago that resolved after 6 days. He is otherwise healthy, lives at home with his mother and 2 cats, has no recent history of travel ,and no sick contacts. On physical examination his temperature is 99°F (37.2°C), blood pressure is 130/85 mmHg, pulse is 80/min, respirations are 19/min, and pulse oximetry is 99% on room air. Cardiopulmonary and abdominal examinations are unremarkable. There is mild periorbital and pedal edema. Urinalysis shows 12-15 RBC/hpf, 2-5 WBC/hpf, and 30 mg/dL protein. Which additional finding would you expect to see on urinalysis?

RBC casts

step1

D

A 65-year-old male with a history of CHF presents to the emergency room with shortness of breath, lower leg edema, and fatigue. He is diagnosed with acute decompensated congestive heart failure, was admitted to the CCU, and treated with a medication that targets beta-1 adrenergic receptors preferentially over beta-2 adrenergic receptors. The prescribing physician explained that this medication would only be used temporarily as its efficacy decreases within one week due to receptor downregulation. Which of the following was prescribed?

Dobutamine

step1

E

A 27-year-old man presents to his primary care physician for his first appointment. He recently was released from prison. The patient wants a checkup before he goes out and finds a job. He states that lately he has felt very fatigued and has had a cough. He has lost roughly 15 pounds over the past 3 weeks. He attributes this to intravenous drug use in prison. His temperature is 99.5°F (37.5°C), blood pressure is 127/68 mmHg, pulse is 100/min, respirations are 18/min, and oxygen saturation is 98% on room air. The patient is started on appropriate treatment. Which of the following is the most likely indication to discontinue this patient's treatment?

Elevated liver enzymes

step2&3

A

A 60-year-old male presents for a routine health check-up. The patient complains of reduced exercise tolerance for the past 2 years. Also, in the past year, he has noticed chest pain after climbing the stairs in his home. He has no significant past medical history or current medications. The patient reports a 45-pack-year smoking history. The vital signs include temperature 37.0°C (98.6°F), blood pressure 160/100 mm Hg, pulse 72/min, respiratory rate 15/min, and oxygen saturation 99% on room air. His body mass index (BMI) is 34 kg/m2. Physical examination is unremarkable. Laboratory studies show: Serum total cholesterol 265 mg/dL HDL 22 mg/dL LDL 130 mg/dL Triglycerides 175 mg/dL HDL: high-density lipoprotein; LDL: low-density lipoprotein Which of the following vascular pathologies is most likely present in this patient?

Atherosclerosis

step1

E

An 88-year-old woman with no significant medical history is brought to the emergency room by her daughter after a fall, where the woman lightly hit her head against a wall. The patient is lucid and complains of a mild headache. The daughter indicates that her mother did not lose consciousness after the fall. On exam, there are no focal neurological deficits, but you decide to perform a CT scan to be sure there is no intracranial bleeding. The CT scan are within normal limits and head MRI is preformed (shown). Which of the following conditions has the most similar risk factor to this patient's condition?

Thoracic aortic aneurysm

step2&3

B

While explaining the effects of hypokalemia and hyperkalemia on the cardiac rhythm, a cardiologist explains that the electrophysiology of cardiac tissue is unique. He mentions that potassium ions play an important role in the electrophysiology of the heart, and the resting membrane potential of the cardiac myocytes is close to the equilibrium potential of K+ ions. This is because of the high resting potassium conductance of the ventricular myocytes, which is regulated by specific potassium channels. These are open at rest and are closed when there is depolarization. Which of the following potassium channels is the cardiologist talking about?

Inward rectifier IK1 potassium channels

step1

A

A 34-year-old man presents to his dermatologist with white scaly papules and plaques on his extensor arms, elbows, knees, and shins. Scaly and flaky eruptions are also present on his ears, eyebrows, and scalp. He describes the lesions as being itchy and irritating. When the scales are scraped away, pinpoint bleeding is noted. His vital signs are unremarkable, and physical examination is otherwise within normal limits. Which of the following is the best initial test for this patient’s condition?

No tests are necessary

step2&3

D

A 35-year-old man presents with a mass on the central part of his neck. He reports it has been growing steadily for the past 2 weeks, and he has also been experiencing fatigue and recurrent fevers. No significant past medical history. The patient denies any smoking history, or alcohol or recreational drug use. He denies any recent travel in the previous 6 months. On physical examination, there are multiple enlarged submandibular and cervical lymph nodes that are firm, mobile, and non-tender. A biopsy of one of the lymph nodes is performed and shows predominantly lymphocytes and histiocytes present in a pattern ‘resembling popcorn’. A flow cytometry analysis demonstrates cells that are CD19 and CD20 positive and CD15 and CD30 negative. Which of the following is the most likely diagnosis in this patient?

Nodular lymphocyte-predominant Hodgkin lymphoma

step1

B

A 3550-g (7-lb 13-oz) male newborn is delivered at 37 weeks' gestation to a 28-year-old woman. Apgar scores are 9 and 10 at 1 and 5 minutes, respectively. His vital signs are within normal limits. Physical examination shows no abnormalities. Routine neonatal screening tests show mildly elevated TSH concentrations. Ultrasonography of the neck shows a complete absence of both lobes of the thyroid gland. This patient's normal physical examination findings, despite the total absence of a thyroid gland, is best explained by which of the following mechanisms?

Transplacental transmission of thyroxine

step1

A

A 2-month-old boy is brought to the physician by his mother because of poor weight gain and irritability since delivery. He is at the 10th percentile for height and below the 5th percentile for weight. Physical examination shows conjunctival pallor. Laboratory studies show: Hemoglobin 11.2 g/dL Mean corpuscular hemoglobin 24.2 pg/cell Mean corpuscular volume 108 μm3 Serum Ammonia 26 μmol/L (N=11–35 μmol/L) A peripheral blood smear shows macrocytosis of erythrocytes and hypersegmented neutrophils. Supplementation with folate and cobalamin is begun. Two months later, his hemoglobin concentration is 11.1 g/dL and mean corpuscular volume is 107 μm3. The patient's condition is most likely caused by failure of which of the following enzymatic reactions?"

Orotate to uridine 5'-monophosphate

step1

E

A previously healthy 40-year-old woman comes to the physician because of a 3-day history of fever, headaches, and fatigue. She also reports a persistent tingling sensation in her right hand and numbness in her right arm that started this morning. Physical examination shows pallor, mild scleral icterus, and petechiae on her forearms and legs. On mental status examination, she appears confused and is only oriented to person. Laboratory studies show: Hemoglobin 11.1 mg/dL Platelet count 39,500/mm3 Bleeding time 9 minutes Prothrombin time 14 seconds Partial thromboplastin time 35 seconds Serum Creatinine 1.7 mg/dL Total bilirubin 2.1 mg/dL A peripheral blood smear shows fragmented erythrocytes. Which of the following is the most likely underlying cause of this patient's condition?"

Antibodies against ADAMTS13

step1

A

A 45-year-old woman comes to the office with a 2-week history of rectal bleeding that occurs every day with her bowel movements. She denies any pain during defecation. Apart from this, she does not have any other complaints. Her past medical history is insignificant except for 5 normal vaginal deliveries. Her vitals are a heart rate of 72/min, a respiratory rate of 15/min, a temperature of 36.7°C (98.1°F), and a blood pressure of 115/85 mm Hg. On rectovaginal examination, there is a palpable, non-tender, prolapsed mass that can be pushed back by the examiner's finger into the anal sphincter. What is the most likely diagnosis?

Hemorrhoids

step1

E

A 60-year-old man comes to the physician’s office with jaundice. Liver ultrasound reveals a shrunken liver and biopsy reveals cirrhosis. Hepatitis serologies are below: Anti-HAV: negative HBsAg: negative HBsAb: positive HBeAg: negative Anti-HBe: negative Anti-HBc: negative Anti-HCV: positive The hepatitis C viral load is 1,000,000 copies/mL. The patient is started on an antiviral regimen including sofosbuvir. What is the mechanism of action of this drug?

Inhibits RNA-dependent RNA polymerase

step1

E

A 55-year-old Chinese man presents to the office with a complaint of progressive unilateral nasal obstruction for 10 months. Though he was able to tolerate his symptoms at the beginning, he can’t breathe properly through the obstructed nostril anymore. Also, a bloody nasal discharge has started recently through the occluded nostril. He also complains of double vision during the past 2 months but did not pay attention to it until now. Past medical history is insignificant except for occasional sore throats. His vitals include: blood pressure of 120/88 mm Hg, respiratory rate of 14/min, pulse of 88/min, temperature 37.0°C (98.6°F). Blood analysis shows: Hemoglobin 15 g/dL Hematocrit 46% Leukocyte count 15000/mm3 Neutrophils 72% Lymphocytes 25% Monocytes 3% Mean corpuscular volume 95 fL Platelet count 350,000/mm3 Which of the following viral etiology is most likely associated with the development of this patient’s condition?

Epstein-Barr virus

step1

C

A 78-year-old man is brought in to the emergency department by ambulance after his wife noticed that he began slurring his speech and had developed facial asymmetry during dinner approximately 30 minutes ago. His past medical history is remarkable for hypertension and diabetes. His temperature is 99.1°F (37.3°C), blood pressure is 154/99 mmHg, pulse is 89/min, respirations are 12/min, and oxygen saturation is 98% on room air. Neurologic exam reveals right upper and lower extremity weakness and an asymmetric smile. Which of the following is the next best step in management?

CT head

step2&3

C

A 7-year-old boy is brought to the physician for recurrent 3–4 minutes episodes of facial grimacing and staring over the past month. He is nonresponsive during these episodes and does not remember them afterward. He recalls a muddy taste in his mouth before the onset of symptoms. One week ago, his brother witnessed an episode where he woke up, stared, and made hand gestures. After the incident, he felt lethargic and confused. Examination shows no abnormalities. Which of the following is the most likely diagnosis?

Complex partial seizure

step1

E

A group of scientists is studying the mechanism by which the human papillomavirus (HPV) vaccine confers immunity. They observe that during the inoculation of test subjects, mammals with certain viral proteins result in the organism’s antigen-presenting cells (APCs) absorbing the antigen and presenting it on major histocompatibility complex (MHC) class 1 molecules. Which of the following is the correct term for the process that the scientists are observing in this inoculation?

Cross-presentation

step1

B

A 21-year-old woman presents with the complaints of nausea, vomiting, and diarrhea for 5 days. She adds that she has fever and abdominal cramping as well. She had recently attended a large family picnic and describes eating many varieties of cold noodle salads. Her past medical history is insignificant. Her temperature is 37.5°C (99.6°F), respiratory rate is 15/min, pulse is 67/min, and blood pressure is 92/68 mm Hg. Physical examination is non-contributory. Given the clinical information provided and most likely diagnosis, which of the following would be the next best step in the management of this patient?

Replacement of fluids and electrolytes

step2&3

B

An investigator is studying biomolecular mechanisms in human cells. A radioactive isotope that is unable to cross into organelles is introduced into a sample of cells. The cells are then fragmented via centrifugation and the isotope-containing components are isolated. Which of the following reactions is most likely to be present in this cell component?

Glucose-6-phosphate to 6-phosphogluconolactone

step1

D

A 30-year-old man comes to the physician for his annual health maintenance examination. The patient has no particular health concerns. He has a history of bilateral cryptorchidism treated with orchidopexy at 8 months of age. This patient is at increased risk for which of the following?

Teratocarcinoma

step1

A

A 28-year-old woman comes to the emergency department because of a 2-day history of dark urine, increasing abdominal pain, and a tingling sensation in her arms and legs. She has a history of epilepsy. Her current medication is phenytoin. She is nauseated and confused. Following the administration of hemin and glucose, her symptoms improve. The beneficial effect of this treatment is most likely due to inhibition of which of the following enzymes?

Aminolevulinate acid synthase

step1

B

A 2-year-old boy is brought to the emergency department by his parents because of fever and recurrent episodes of jerky movements of his extremities for the past 6 hours. Pregnancy and delivery were uncomplicated, and development was normal until the age of 1 year. The parents report that he has had gradual loss of speech, vision, and motor skills over the past year. During this time, he has been admitted to the hospital three times because of myoclonic seizures. Physical examination shows hypertonicity of the upper and lower extremities. Fundoscopic examination shows pallor of the optic disc bilaterally. An MRI of the brain shows brain atrophy and hyperintensity of the periventricular and subcortical areas. Two days after admission, the patient dies. Histopathologic examination of the brain shows aggregation of globoid cells and loss of glial cells. The patient’s condition was most likely caused by a deficiency of which of the following enzymes?

β-Galactocerebrosidase

step1

E

An obese, 66-year-old woman comes to the physician for a routine health maintenance examination. She feels well but is unhappy about being overweight. She reports that she feels out of breath when walking for more than one block and while climbing stairs. She has tried to lose weight for several years without success. She goes for a walk 3 times a week but she has difficulty following a low-calorie diet. During the past 12 months, she has had two urinary tract infections that were treated with fosfomycin. She has type 2 diabetes mellitus and osteoarthritis. Her only current medication is metformin. She has never smoked. She is 160 cm (5 ft 3 in) tall and weighs 100 kg (220 lb); BMI is 39.1 kg/m2. Vital signs are within normal limits. Physical examination shows cracking in both knees on passive movement. The remainder of the examination shows no abnormalities. Serum studies show an HbA1c of 9.5%, and a fasting serum glucose concentration of 158 mg/dL. An ECG shows no abnormalities. Which of the following is the most appropriate pharmacotherapy?

Exenatide

step2&3

B

A 62-year-old man comes to the physician for a follow-up examination. One month ago, therapy with lisinopril was initiated for treatment of hypertension. His blood pressure is 136/86 mm Hg. Urinalysis shows a creatinine clearance of 92 mL/min. The patient's serum creatinine concentration is most likely closest to which of the following values?

1.1 mg/dL

step1

D

A 21-year-old woman presents to the emergency department with complaints of intermittent bouts of lower abdominal and pelvic pain over the last week. The pain is primarily localized to the right side and is non-radiating. The patient is not sexually active at this time and is not currently under any medication. At the hospital, her vitals are normal. A pelvic examination reveals a tender palpable mass on the right adnexal structure. A pelvic CT scan reveals a 7-cm solid adnexal mass that was surgically removed with the ovary. Histological evaluation indicates sheets of uniform cells resembling a 'fried egg', consistent with dysgerminoma. Which of the following tumor markers is most likely elevated with this type of tumor?

Lactate dehydrogenase (LDH)

step2&3

A

A 25-year-old woman, gravida 2, para 1, comes to the physician for her initial prenatal visit at 18 weeks’ gestation. She is a recent immigrant from Thailand. Her history is significant for anemia since childhood that has not required any treatment. Her mother and husband have anemia, as well. She has no history of serious illness and takes no medications. Her vital signs are within normal limits. Fundal height measures at 22 weeks. Ultrasound shows polyhydramnios and pleural and peritoneal effusion in the fetus with fetal subcutaneous edema. Which of the following is the most likely clinical course for this fetus?

Intrauterine fetal demise

step2&3

C

A 62-year-old woman comes to the physician because of increasing blurring of vision in both eyes. She says that the blurring has made it difficult to read, although she has noticed that she can read a little better if she holds the book below or above eye level. She also requires a bright light to look at objects. She reports that her symptoms began 8 years ago and have gradually gotten worse over time. She has hypertension and type 2 diabetes mellitus. Current medications include glyburide and lisinopril. When looking at an Amsler grid, she says that the lines in the center appear wavy and bent. An image of her retina, as viewed through fundoscopy is shown. Which of the following is the most likely diagnosis?

Age-related macular degeneration "

step2&3

E