Internal Medicine

A 68-year-old man is evaluated in the hospital for decreased urine output. He was admitted 3 days ago for severe gastroenteritis and has had poor oral intake. His blood pressure is $96/60 \text{ mm Hg}$ and heart rate is $112/\text{min}$. Physical examination reveals dry oral mucosa and delayed capillary refill. Laboratory studies show:

Based on these laboratory findings, what is the patient's calculated fractional excretion of sodium (expressed as a percentage)?

A 35-year-old woman comes to the clinic for evaluation of profound fatigue, a 6-kg (13.2-lb) weight gain, and feeling constantly cold over the past 8 months. She also reports that her menstrual periods have been absent for the past 6 months. Her last pregnancy was 4 years ago and was uncomplicated. She takes no medications. Vital signs show a blood pressure of 110/70 mm Hg and a heart rate of 56/min. Physical examination reveals dry, pale skin and delayed relaxation of the deep tendon reflexes. A urine pregnancy test is negative. Laboratory evaluation shows:

Which of the following is the most likely underlying mechanism for this patient's clinical presentation?

During morning rounds, the internal medicine team evaluates a male patient in his late fifties who was admitted three days prior for community-acquired pneumonia. On presentation to the emergency department, his temperature was $39.2^\circ\text{C}$ ($102.6^\circ\text{F}$) and chest imaging revealed a right lower lobe consolidation. Initial empiric therapy with intravenous ceftriaxone and oral azithromycin was instituted.

Currently, the patient reports significant symptomatic improvement, noting decreased cough and resolution of shortness of breath. He is comfortably eating a regular diet. His vital signs show a temperature of $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure of $124/82\text{ mm Hg}$, heart rate of $78/\text{min}$, and respiratory rate of $16/\text{min}$.

A high-quality sputum specimen collected prior to antibiotic administration has grown heavy *Streptococcus pneumoniae*. Antimicrobial susceptibility testing indicates that the organism is sensitive to penicillin, amoxicillin, ceftriaxone, and levofloxacin, but demonstrates resistance to macrolides.

Which of the following is the most appropriate next step in the pharmacologic management of this patient?

A 42-year-old woman is brought to the emergency department by her husband due to severe agitation, palpitations, vomiting, and high fever. She has a history of Graves disease but stopped taking her antithyroid medications three months ago. Her temperature is 39.7°C (103.5°F), blood pressure is 155/75 mmHg, and heart rate is 148/min and regular. Physical examination reveals a fine hand tremor, significant diaphoresis, lid lag, and a diffusely enlarged, non-tender thyroid gland. An electrocardiogram demonstrates sinus tachycardia. The clinical diagnosis of thyroid storm is suspected. Arrange the following interventions in the most appropriate chronological order of administration for this patient's acute to long-term management.

A 59-year-old man with a history of alcoholic cirrhosis and esophageal varices is hospitalized due to generalized abdominal pain and a low-grade fever. On admission, his temperature is 38.1 °C (100.6 °F), blood pressure is 105/65 mmHg, and heart rate is 98/min. Physical examination reveals scleral icterus, spider angiomata, and a distended abdomen with shifting dullness and diffuse mild tenderness.

A diagnostic paracentesis yields cloudy ascitic fluid with a leukocyte count of 1,200/mm³ and a neutrophil count of 950/mm³. He is immediately started on intravenous albumin and empiric intravenous piperacillin-tazobactam.

On hospital day 3, the patient is afebrile and reports significant improvement in his abdominal pain. Ascitic fluid cultures from admission grow *Klebsiella pneumoniae*. Susceptibility testing indicates the isolate is resistant to ampicillin, but susceptible to ceftriaxone, cefotaxime, ciprofloxacin, and piperacillin-tazobactam. Blood cultures show no growth.

Which of the following is the most appropriate next step in the antimicrobial management of this patient?

A 29-year-old woman, gravida 1 para 0, at 28 weeks gestation is brought to the emergency department due to sudden-onset, severe shortness of breath and a cough productive of pink-tinged sputum. She immigrated to the United States two years ago and has not received routine prenatal care. Vital signs show a blood pressure of 110/70 mmHg, a pulse of 118/min, and a respiratory rate of 28/min. Oxygen saturation is 88% on room air. Physical examination reveals a gravid uterus consistent with dates. Auscultation of the lungs demonstrates bilateral basilar crackles. Cardiac examination reveals a loud first heart sound (S1) and a low-pitched, rumbling mid-diastolic murmur heard best at the cardiac apex. Which of the following underlying mechanisms best explains the acute onset of this patient's respiratory symptoms?

A 32-year-old woman comes to the clinic reporting profound fatigue, weight loss, and lightheadedness upon standing over the past 3 months. She delivered a healthy infant 4 months ago. Her delivery was complicated by severe uterine atony and hemorrhage, requiring massive fluid resuscitation and the transfusion of 3 units of packed red blood cells. Since the delivery, she has been unable to breastfeed and has not resumed menstruation. Her blood pressure is 92/58 mm Hg and pulse is 95/min. Laboratory studies show:

The physician suspects a thyroid disorder and considers initiating levothyroxine therapy. Which of the following is the most appropriate next step in management prior to initiating this medication?

A 62-year-old man presents to a rural emergency department with crushing substernal chest pain that began 45 minutes ago. His blood pressure is $130/80\text{ mmHg}$, and his heart rate is $88/\text{min}$. An electrocardiogram reveals $4\text{ mm}$ ST-segment elevations in leads II, III, and aVF. The hospital does not have a cardiac catheterization laboratory. The nearest percutaneous coronary intervention (PCI)-capable center is 150 minutes away by helicopter due to current weather conditions.

Arrange the following management steps in the most appropriate chronological order according to standard guidelines.

A 58-year-old man suddenly collapses while walking in the hospital lobby. He is unresponsive, lacks a palpable pulse, and is not breathing. The emergency response team arrives and attaches a cardiac monitor, which reveals ventricular fibrillation. According to the Advanced Cardiac Life Support (ACLS) algorithm for adult cardiac arrest, arrange the following subsequent management steps in the correct chronological sequence.

A $28$-year-old man comes to the clinic due to a $4$-week history of abdominal pain, non-bloody diarrhea, and a $4$-kg ($8.8$-lb) weight loss. He has $4$ to $5$ loose bowel movements daily. The abdominal pain is cramping in nature and localizes to the right lower quadrant. He has a history of mild asthma. Vital signs are temperature $37.3^\circ\text{C}$ ($99.1^\circ\text{F}$), pulse $86/\text{min}$, and blood pressure $118/76\text{ mmHg}$. Physical examination reveals a soft, non-distended abdomen with moderate tenderness to deep palpation in the right lower quadrant. There is no rebound tenderness, guarding, or palpable mass. Bowel sounds are normal.

Laboratory studies show:

Stool studies for ova and parasites, routine bacterial pathogens, and *Clostridioides difficile* toxin are negative. A recent colonoscopy performed $2$ months ago for chronic diarrhea showed patchy areas of mucosal inflammation, erythema, and deep ulcerations in the terminal ileum, with a normal-appearing colon.

Which of the following is the most appropriate next step in management?

Correlate each of the described clinical scenarios with its characteristic pattern of thyroid function testing.

A 19-year-old woman is brought to the emergency department by her college roommate due to confusion, nausea, and ringing in her ears that started 4 hours ago. The roommate reports that the patient was distraught after a recent argument, and an empty bottle of over-the-counter pain medication was found on her desk. Vital signs show a temperature of $37.8^\circ$ C ($100.0^\circ$ F), blood pressure of $110/70$ mmHg, pulse of $115$/min, and respiratory rate of $28$/min. Physical examination reveals an oriented but lethargic patient. Lungs are clear to auscultation. Laboratory studies are obtained and show the following:

Serum sodium: $142$ mEq/L
Serum potassium: $4.0$ mEq/L
Serum chloride: $104$ mEq/L
Serum bicarbonate: $14$ mEq/L
Blood urea nitrogen: $18$ mg/dL
Serum creatinine: $0.9$ mg/dL

Arterial blood gas (room air):
pH: $7.42$
pCO $_2$: $20$ mmHg
pO $_2$: $105$ mmHg

Based on the laboratory results, which of the following best describes this patient's acid-base disturbance?

A 28-year-old man presents to the emergency department with a 4-day history of high fevers, chills, and sharp, pleuritic chest pain. He also reports a cough productive of scant, blood-tinged sputum. His temperature is $39.1^\circ\text{C}$ ($102.4^\circ\text{F}$), blood pressure is $112/68\text{ mmHg}$, pulse is $118/\text{min}$, and respiratory rate is $22/\text{min}$. Oxygen saturation is $94\%$ on room air. Physical examination reveals prominent needle track marks on his forearms. Cardiac auscultation demonstrates a grade $3/6$ holosystolic murmur at the left lower sternal border; the murmur's intensity increases significantly during inspiration. Pulmonary auscultation reveals scattered crackles in both lung fields. A chest radiograph demonstrates multiple bilateral peripheral nodular opacities, several of which have central cavitation. Three sets of blood cultures are obtained. Which of the following is the most appropriate initial pharmacotherapy for this patient?

A 68-year-old man comes to the emergency department complaining of worsening shortness of breath, a persistent nonproductive cough, and swelling in his legs over the past 4 days. He has a 40-pack-year smoking history and a medical history of hypertension, hyperlipidemia, and type 2 diabetes mellitus. His current medications include amlodipine, lisinopril, atorvastatin, and metformin. His temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $162/92\text{ mmHg}$, pulse is $106/\text{min}$, and respirations are $24/\text{min}$. Pulse oximetry shows an oxygen saturation of $92\%$ on room air. Physical examination reveals a patient in mild respiratory distress using accessory muscles of respiration. Jugular venous pressure is elevated at $12\text{ cm H}_2\text{O}$. Lung auscultation reveals bilateral diffuse expiratory wheezes and dullness to percussion at both bases. Cardiac examination shows a regular rhythm, tachycardia, and a third heart sound (S3). Trace bilateral pitting edema is present up to the ankles. An electrocardiogram shows sinus tachycardia with no acute ischemic changes. Which of the following is the most appropriate initial therapy for this patient's current condition?

An emergency medical responder brings a 73-year-old retired construction worker to the emergency department after his wife noticed severe swelling in his legs and progressive difficulty breathing over the past three weeks. The patient has a 50-pack-year smoking history but has not been evaluated by a physician in more than a decade. Vital signs show a temperature of 37.1°C, blood pressure of 138/84 mm Hg, pulse of 108/min, and respiratory rate of 24/min. Oxygen saturation is 88% on room air.

Physical examination reveals an increased anteroposterior diameter of the chest. Lung auscultation demonstrates globally decreased breath sounds with a prolonged expiratory phase. Jugular venous pressure is visibly elevated to 11 cm H2O and features a prominent *a* wave. Cardiac examination reveals a pronounced impulse along the left lower sternal border. A soft, high-pitched, blowing, early diastolic murmur is heard best at the second left intercostal space. The liver edge is palpable 4 cm below the right costal margin, and there is 2+ bilateral pitting edema extending to the knees.

A portable chest radiograph demonstrates hyperlucent lung fields, flattened diaphragms, and prominent central pulmonary arteries without pleural effusions or pulmonary infiltrates. Electrocardiography shows right axis deviation and peaked P waves in lead II.

Which of the following is the most likely initiating mechanism for this patient's cardiac findings?

A 48-year-old man is brought to the emergency department due to excruciating lower chest and upper abdominal pain that began 2 hours ago. The pain started abruptly after several episodes of forceful retching and vomiting following heavy alcohol consumption. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), blood pressure is $105/65\text{ mmHg}$, pulse is $118/\text{min}$, and respirations are $24/\text{min}$. Physical examination reveals diaphoresis and acute distress. Palpation of the anterior neck and supraclavicular area elicits a crackling sensation. Cardiac auscultation reveals a crunching sound synchronous with the heartbeat.

Arrange the following diagnostic and therapeutic steps in the most appropriate sequential order for managing this patient, assuming the initial contrast study is non-diagnostic but clinical suspicion remains high.

A 42-year-old man is brought to the emergency department by ambulance after being found unresponsive in his garage. His wife reports that he has a history of major depressive disorder and recently lost his job. On physical examination, he is unarousable. Blood pressure is 115/75 mm Hg, pulse is 112/min, and respirations are 24/min and deep.

Laboratory studies show:
Serum sodium: 140 mEq/L
Serum potassium: 4.6 mEq/L
Serum chloride: 105 mEq/L
Serum bicarbonate: 10 mEq/L
Blood urea nitrogen (BUN): 28 mg/dL
Serum creatinine: 1.8 mg/dL
Serum glucose: 108 mg/dL
Measured serum osmolality: 320 mOsm/kg H2O

What is this patient's serum osmolar gap in mOsm/kg H2O?

A 45-year-old man presents to the emergency department complaining of a 4-week history of productive cough, intermittent hemoptysis, drenching night sweats, and an unintentional 5-kg (11-lb) weight loss. He recently emigrated from a country with a high prevalence of tuberculosis. His temperature is 38.2°C (100.8°F), blood pressure is 120/78 mm Hg, pulse is 92/min, and respiratory rate is 18/min. A portable chest radiograph performed in the triage area reveals a cavitary lesion in the right upper lobe. The patient is currently sitting in a standard shared emergency department waiting area. Arrange the following steps in the most appropriate sequential order for the management of this patient.

Match each of the following dynamic auscultation findings with the most likely underlying structural or valvular pathology.

A 62-year-old man is brought to the emergency department by his wife due to progressive confusion, lethargy, and worsening shortness of breath over the past 48 hours. He has a history of alcohol-associated cirrhosis, heart failure with preserved ejection fraction, and hypothyroidism. Home medications include lactulose, nadolol, spironolactone, furosemide, and levothyroxine. His wife notes that he doubled his furosemide dose three days ago because his abdomen felt "tighter than usual."

Vital signs are:
Temperature: 37.1°C (98.8°F)
Blood pressure: 105/65 mm Hg
Pulse: 98/min
Respirations: 22/min
Oxygen saturation: 94% on room air

Physical examination reveals a lethargic man who is oriented only to person. Scleral icterus and multiple spider angiomata are present. Breath sounds are diminished at the right lung base with dullness to percussion. The abdomen is markedly distended and tense, with shifting dullness. When the patient holds his arms outstretched with wrists extended, a coarse, flapping tremor is observed.

Laboratory results:
Sodium: 131 mEq/L
Potassium: 2.7 mEq/L
Chloride: 88 mEq/L
Bicarbonate: 35 mEq/L
Blood urea nitrogen: 38 mg/dL
Creatinine: 1.5 mg/dL
Leukocyte count: 7,500/mm³
Hemoglobin: 11.2 g/dL
Platelets: 85,000/mm³
TSH: 2.1 µU/mL (Normal: 0.4-4.0 µU/mL)
Free T4: 1.2 ng/dL (Normal: 0.8-1.8 ng/dL)

Arterial blood gas on room air:
pH: 7.51
PaCO2: 45 mm Hg
PaO2: 70 mm Hg

A diagnostic paracentesis yields clear yellow fluid with a neutrophil count of 120/mm³. Chest radiography reveals a small right-sided pleural effusion without focal consolidations.

In addition to optimizing his lactulose therapy, which of the following is the most appropriate next step in the management of this patient?