Internal Medicine

A 19-year-old college student is brought to the emergency department by his roommates. They report that he ingested a large amount of a sweet-tasting, brightly colored liquid he found in a garage, believing it was a sports drink. On presentation, he is disoriented and slurring his words. His blood pressure is 120/75 mm Hg and his pulse is 100/min.

Laboratory studies:
- Serum sodium: 142 mEq/L
- Serum chloride: 105 mEq/L
- Serum bicarbonate: 14 mEq/L
- Blood urea nitrogen: 14 mg/dL
- Blood glucose: 90 mg/dL
- Measured serum osmolality: 345 mOsm/kg $H_2O$

What is this patient's serum osmolar gap in mOsm/kg $H_2O$?

A $34$-year-old woman presents to the clinic with a $6$-month history of worsening fatigue, cold intolerance, and constipation. She also reports frequent dizziness upon standing, intermittent nausea, and a $4$-kg ($8.8$-lb) weight loss. Her medical history is notable for a complicated vaginal delivery $2$ years ago that was followed by massive postpartum hemorrhage requiring multiple blood transfusions. She has been amenorrheic since the delivery and was unable to lactate.

Her blood pressure is $102/68$ mm Hg while supine and $84/56$ mm Hg while standing. Her heart rate is $82$/min. Physical examination shows delayed relaxation of deep tendon reflexes and loss of pubic and axillary hair.

Laboratory results are as follows:

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

A 29-year-old man comes to the clinic for a follow-up examination. Over the past 4 months, he has experienced profound fatigue, cold intolerance, a 6-kg (13.2-lb) weight gain, and decreased libido. Eight months ago, he was involved in a severe motorcycle collision that resulted in a traumatic brain injury. He spent 3 weeks in the intensive care unit but has since been participating in a physical rehabilitation program. His current medications include ibuprofen as needed for occasional headache. Blood pressure is 106/68 mm Hg and pulse is 56/min. Physical examination reveals dry skin, loss of axillary and pubic hair, and a delayed relaxation phase of the deep tendon reflexes. Laboratory studies show:

Which of the following is the most likely explanation for this patient's clinical and laboratory findings?

Match the following clinical presentations and corresponding high-resolution manometry (HRM) metrics to the most appropriate esophageal motility disorder.

Following treatment for a newly diagnosed deep venous thrombosis, a $45$-year-old woman develops severe, worsening pain over her abdomen and left thigh. She sought care at an urgent care clinic $3$ days prior for left leg swelling and was immediately prescribed oral warfarin monotherapy. Her past medical history is significant for obesity and type $2$ diabetes mellitus. Current medications include metformin and warfarin. Her temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $134/82\text{ mmHg}$, and pulse is $88/\text{min}$. Physical examination reveals well-demarcated, exquisitely tender, purpuric lesions with central black eschars over her abdomen and thighs. The remainder of the examination is unremarkable. Laboratory studies show:

Hemoglobin: $13.2\text{ g/dL}$
Platelets: $210,000/\text{mm}^3$
Leukocytes: $7,500/\text{mm}^3$
Prothrombin time: $24\text{ seconds}$ (INR: $2.2$)
Activated partial thromboplastin time: $32\text{ seconds}$

Which of the following is the most likely underlying mechanism for this patient's current skin findings?

Match each valvular heart disease with its most characteristic auscultatory physical exam finding.

A physician is evaluating four patients who present with pronounced polyuria and polydipsia. Match each patient's clinical vignette with the most likely corresponding laboratory profile observed during a diagnostic water deprivation test and subsequent administration of exogenous desmopressin.

A $48$-year-old man presents for a follow-up visit regarding his hypertension. He is currently taking maximum tolerated doses of lisinopril, amlodipine, and hydrochlorothiazide. His blood pressure is $168/102$ mmHg. Laboratory studies reveal a serum sodium of $143$ mEq/L and a serum potassium of $2.8$ mEq/L. The patient is suspected to have a secondary cause of hypertension. Arrange the following diagnostic and management steps in the most appropriate chronological sequence for the evaluation and definitive management of this patient's suspected condition.

A 64-year-old man is evaluated in the hospital for a 3-week history of progressive abdominal distension and worsening exertional dyspnea. He denies fever, orthopnea, or abdominal pain. Medical history is significant for severe chronic obstructive pulmonary disease (COPD) treated with inhaled fluticasone and umeclidinium-vilanterol. He has a 40-pack-year smoking history.

Vital signs include a temperature of 37.1°C (98.8°F), blood pressure of 118/74 mmHg, pulse of 92/min, and respiratory rate of 18/min. Pulse oximetry is 93% on room air.

Physical examination reveals an estimated jugular venous pressure of 12 cm H₂O. Pulmonary auscultation reveals scattered expiratory wheezes with a prolonged expiratory phase. The abdomen is distended with shifting dullness and a positive fluid wave. A firm, smooth liver edge is palpated 4 cm below the right costal margin. Trace bilateral lower extremity pitting edema is present.

Diagnostic laboratory testing reveals the following:

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

An alert 42-year-old female is evaluated in the urgent care clinic for persistent weakness, severe muscle cramps, and three days of voluminous, watery stools after attending a community barbecue. Her past medical history is significant for severe obesity and obstructive sleep apnea, for which she uses continuous positive airway pressure (CPAP) inconsistently at night. Vital signs show a temperature of 37.4°C (99.3°F), pulse of 108/min, respirations of 22/min, and blood pressure of 102/64 mmHg. Physical examination reveals dry mucous membranes and decreased skin turgor. The following laboratory values are reported:

Based on the provided laboratory values and clinical presentation, which of the following best characterizes this patient's acid-base status?

A $58$-year-old man with decompensated cirrhosis due to alcohol use disorder is evaluated on hospital day $3$ for ongoing management of spontaneous bacterial peritonitis. He initially presented with a temperature of $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), diffuse abdominal pain, and confusion. Diagnostic paracentesis on admission showed an ascitic fluid absolute neutrophil count of $850/\text{mm}^3$. Because of a history of extended-spectrum beta-lactamase (ESBL)-producing *Escherichia coli* bacteriuria $6$ months ago, he was empirically started on intravenous meropenem. Intravenous albumin ($1.5$ g/kg) was also administered on admission based on the following laboratory results:

Admission (Day 1):
Blood urea nitrogen: $34$ mg/dL
Serum creatinine: $1.5$ mg/dL
Total bilirubin: $5.2$ mg/dL

Today (Day 3), the patient is feeling much better. His temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), and his mental status has returned to baseline. Ascitic fluid cultures from admission have grown *Klebsiella pneumoniae*. Antimicrobial susceptibility testing is as follows:
Ampicillin: Resistant
Ceftriaxone: Susceptible
Ciprofloxacin: Susceptible
Meropenem: Susceptible
Piperacillin-tazobactam: Susceptible

Current laboratory results:
Blood urea nitrogen: $24$ mg/dL
Serum creatinine: $1.1$ mg/dL
Total bilirubin: $4.5$ mg/dL

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

A 55-year-old man with a history of intravenous drug use comes to the emergency department reporting severe, unrelenting lower back pain for the past 3 weeks. The pain is worse at night, is not relieved by rest, and is accompanied by subjective fevers. He reports no leg weakness, numbness, or bowel and bladder incontinence. Temperature is 38.2°C (100.8°F), pulse is 92/min, and blood pressure is 128/78 mm Hg. Physical examination shows focal tenderness to percussion over the L4 and L5 spinous processes. Neurologic examination of the lower extremities reveals full strength, normal sensation, and intact reflexes bilaterally. Arrange the following steps in the most appropriate chronological sequence for the diagnostic workup and management of this patient.

A $58$-year-old man with a history of cirrhosis secondary to untreated hepatitis C is admitted to the hospital due to progressive lethargy and abdominal distension over the past $48$ hours. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), pulse is $102/\text{min}$, blood pressure is $105/65\text{ mmHg}$, and respirations are $18/\text{min}$. Physical examination reveals scleral icterus, a distended abdomen with shifting dullness, and diffuse mild tenderness without rebound or guarding. Asterixis is present.

Laboratory studies show:

A diagnostic paracentesis is performed:

The patient is immediately started on intravenous cefotaxime. Which of the following is the most appropriate additional step in this patient's management?

A 32-year-old woman comes to the emergency department complaining of sudden-onset palpitations and mild shortness of breath that started 30 minutes ago. She has no significant past medical history. Her temperature is 37.0°C (98.6°F), blood pressure is 118/76 mmHg, pulse is 185/min, and respiratory rate is 18/min. Pulse oximetry is 99% on room air. An electrocardiogram reveals a regular, narrow-complex tachycardia with no discernible P waves. Assuming each subsequent intervention fails to terminate the arrhythmia and the patient remains hemodynamically stable until the final step, arrange the following management options in the correct sequential order from first to last according to standard treatment algorithms.

A 68-year-old man is brought to the emergency department by his daughter due to a 1-day history of fever, severe right upper quadrant abdominal pain, and new-onset confusion. His temperature is 39.4°C (102.9°F), blood pressure is 86/52 mm Hg, and pulse is 122/min. Physical examination reveals scleral icterus and marked right upper quadrant tenderness to palpation with guarding. Laboratory studies show a leukocyte count of 18,500/mm³, an elevated direct bilirubin level, and elevated alkaline phosphatase. Arrange the following management steps in the most appropriate chronological sequence for this patient.

Review the following diagnostic laboratory profiles of patients presenting with cushingoid features (such as central obesity, proximal muscle weakness, and abdominal striae). Match each laboratory and testing profile with its most appropriate underlying pathophysiologic etiology.

A medical team is rounding on a $59$-year-old man admitted $3$ days ago with fever, abdominal pain, and confusion. He has a known history of decompensated cirrhosis due to chronic hepatitis C. At the time of admission, an emergency diagnostic paracentesis yielded cloudy fluid with an absolute neutrophil count of $850/\text{mm}^3$, confirming spontaneous bacterial peritonitis. Because he had been hospitalized $4$ weeks prior for a variceal bleed, the inpatient team initiated empiric therapy with intravenous piperacillin-tazobactam to cover potential healthcare-associated pathogens.

Currently, the patient is clinically stable. His confusion has cleared, and he reports no abdominal pain. Vital signs today show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure of $112/70\,\text{mmHg}$, and a heart rate of $78/\text{min}$. The microbiology laboratory reports that the admission ascitic fluid culture is positive for *Escherichia coli*. Antimicrobial susceptibility testing demonstrates that the isolate is sensitive to ceftriaxone, cefotaxime, and ciprofloxacin, but resistant to ampicillin.

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

A 72-year-old man with a history of advanced prostate cancer presents to the emergency department with severe, progressively worsening mid-back pain over the past two weeks. Over the last 24 hours, he has developed bilateral lower extremity weakness and difficulty voiding urine. Neurological examination reveals 3/5 strength in the bilateral lower extremities, decreased sensation to pinprick below the umbilicus, and hyperreflexia at the knees. A diagnosis of malignant epidural spinal cord compression (MESCC) is highly suspected. Arrange the following management steps in the correct chronological order.

Match each clinical presentation of shock with its most characteristic invasive hemodynamic profile (Central Venous Pressure [CVP], Pulmonary Capillary Wedge Pressure [PCWP], Cardiac Index [CI], and Systemic Vascular Resistance [SVR]).

A 55-year-old male presents to the triage desk of the local hospital reporting progressive difficulty breathing that began two days ago. He states that he has been unable to sleep in his bed due to a feeling of suffocation and has been resting in a recliner chair. He also notes a new cough that occasionally produces pink, frothy sputum. Medical history is significant for essential hypertension, type 2 diabetes mellitus, and a 40-pack-year smoking history. Current medications include lisinopril, amlodipine, and metformin. Vital signs demonstrate a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure of $178/102$ mmHg, pulse of 112/min, and respiratory rate of 26/min. Pulse oximetry reveals an oxygen saturation of 89% on room air. On physical examination, the patient appears distressed and is using accessory muscles to breathe. Evaluation of the neck shows jugular venous distention up to the angle of the mandible while seated upright. Cardiac auscultation is notable for a regular, rapid rhythm and a low-frequency diastolic sound heard best at the cardiac apex. Lung auscultation reveals bilateral expiratory wheezes and fine crackles extending from the bases to the mid-lung zones. Which of the following is the most appropriate initial pharmacologic therapy for this patient?