Internal Medicine

An outpatient evaluation is requested for a 35-year-old woman complaining of new-onset profound generalized weakness and intermittent palpitations over the past two weeks. Her medical history is notable for rheumatoid arthritis and severe dry eyes, for which she frequently uses artificial tears. Her blood pressure is $118/76 \text{ mmHg}$ and heart rate is $92\text{/min}$. Laboratory studies show the following:

Urinalysis demonstrates a $pH$ of $6.5$, with no glucose, protein, or blood. Urine electrolytes reveal a sodium of $45 \text{ mEq/L}$, potassium of $25 \text{ mEq/L}$, and chloride of $50 \text{ mEq/L}$. Which of the following best describes the underlying pathophysiologic defect in this patient?

A $25$-year-old woman with a $4$-year history of ileocolonic Crohn disease is evaluated in the hospital on day $4$ of her admission. She originally presented with fever, right lower quadrant abdominal pain, and leukocytosis. A computed tomography scan of the abdomen on admission revealed acute terminal ileitis complicated by a $4.5\text{-cm}$ adjacent fluid collection. She was empirically started on intravenous piperacillin-tazobactam, and a percutaneous drain was successfully placed by interventional radiology on hospital day $1$.

Today, the patient feels much better. She is tolerating a low-residue diet and her abdominal pain has largely resolved. Her temperature is $37.3^\circ\text{C} (99.1^\circ\text{F})$, pulse is $82/\text{min}$, and blood pressure is $118/76\text{ mm Hg}$. Her leukocyte count has decreased from $16,000/\text{mm}^3$ to $8,200/\text{mm}^3$. The percutaneous drain has output only $5\text{ mL}$ of serous fluid over the past $24$ hours. Abscess fluid cultures have finalized, growing *Escherichia coli* and *Bacteroides fragilis*. Susceptibility testing demonstrates that both organisms are susceptible to amoxicillin-clavulanate. The *E. coli* isolate is susceptible to ciprofloxacin and ceftriaxone, and the *B. fragilis* isolate is susceptible to metronidazole.

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

A 68-year-old man is brought to the emergency department from a nursing facility due to fever, cough, and progressive lethargy over the past 2 days. His medical history is significant for chronic kidney disease, hypertension, and benign prostatic hyperplasia. Temperature is 38.8°C (101.8°F), blood pressure is 88/54 mm Hg, pulse is 112/min, and respiratory rate is 22/min with shallow breathing. Physical examination reveals crackles in the right lower lung base and delayed capillary refill. The patient is somnolent and only arouses to painful stimuli.

Arterial blood gas (room air):
- pH: 7.08
- $pCO_2$: 35 mm Hg
- $pO_2$: 65 mm Hg

Serum chemistries:
- Sodium: 138 mEq/L
- Potassium: 4.5 mEq/L
- Chloride: 102 mEq/L
- Bicarbonate: 10 mEq/L
- Blood urea nitrogen: 45 mg/dL
- Creatinine: 2.8 mg/dL
- Lactate: 5.2 mmol/L (Normal 0.5-1.5 mmol/L)

Which of the following best characterizes this patient's current acid-base status?

A 72-year-old man with a history of IgG kappa multiple myeloma, chronic obstructive pulmonary disease (COPD), and heart failure with preserved ejection fraction is admitted for symptomatic anemia. His hemoglobin is 6.8 g/dL, and a transfusion of packed red blood cells is initiated. Two hours later, he develops acute-onset respiratory distress. The transfusion is immediately stopped.

Vital signs are temperature 37.1°C (98.8°F), blood pressure 175/95 mm Hg, pulse 115/min, and respirations 28/min. Pulse oximetry is 85% on room air. Physical examination shows an anxious patient in moderate respiratory distress with prominent jugular venous distension. Chest auscultation reveals bilateral basilar crackles, diffuse end-expiratory wheezing, and a third heart sound (S3).

Laboratory studies from admission show:

A urine culture obtained at admission for routine screening grew >100,000 CFU/mL of *Escherichia coli* that is sensitive to all tested antibiotics, including amoxicillin and cephalexin. The patient denies dysuria.

The patient's daughter, who holds a valid healthcare proxy and previously confirmed the patient's wish for full medical interventions, is en route to the hospital. The patient's estranged son is currently at the bedside and demands that the team withhold all respiratory and fluid management to transition the patient immediately to comfort care.

Which of the following is the most appropriate next step in the management of this patient's acute respiratory distress?

A 34-year-old female is evaluated at the outpatient clinic for persistent exhaustion, a 5-kg (11-lb) weight loss, and failure to resume menses over the past 8 months. Her symptoms began shortly after the delivery of her first child, which was complicated by a prolonged labor and massive postpartum hemorrhage requiring surgical intervention and multiple blood transfusions. She notes feeling lightheaded upon standing and reports she was never able to produce breast milk. Vital signs show a blood pressure of 88/56 mm Hg sitting and 74/48 mm Hg upon standing. Heart rate is 62/min.

Laboratory evaluation shows:
Serum sodium: 128 mEq/L
Serum potassium: 4.0 mEq/L
Thyroid-stimulating hormone (TSH): 1.4 mIU/L (normal: 0.4–4.0 mIU/L)
Free thyroxine (T4): 0.5 ng/dL (normal: 0.9–1.7 ng/dL)

The physician diagnoses hypothyroidism based on the peripheral hormone levels and plans to begin thyroxine replacement therapy. Which of the following is the most appropriate next step in management prior to initiating this medication?

Emergency medical services bring a 71-year-old retired architect to the emergency department due to progressively worsening difficulty breathing over the last 72 hours. He reports waking up multiple times during the night feeling starved for air and ultimately having to sleep sitting up in a recliner. His medical history is significant for essential hypertension, type 2 diabetes mellitus, and a 40-pack-year smoking history. His temperature is 37.1°C (98.8°F), blood pressure is 158/92 mm Hg, pulse is 96/min, and respirations are 24/min. Pulse oximetry shows 91% on room air. Physical examination reveals elevated jugular venous pressure, visible 9 cm above the sternal angle. Cardiac auscultation reveals a normal S1 and S2 with an additional low-pitched sound heard in early diastole. Pulmonary auscultation demonstrates bilateral crackles extending to the mid-lung fields and trace scattered expiratory wheezing. Arterial blood gas analysis on room air reveals a pH of 7.32, $PaCO_2$ of 46 mm Hg, and $PaO_2$ of 64 mm Hg. Which of the following is the most appropriate initial management for this patient?

Match the following clinical presentations in patients with advanced HIV/AIDS to their most appropriate definitive pharmacotherapy.

An oncologist is asked to evaluate a 54-year-old man admitted for profound neutropenia following induction chemotherapy for acute myeloid leukemia. For the past 5 days, he has been treated with intravenous cefepime for a temperature of 39.2°C (102.6°F) and an absolute neutrophil count of 150/mm³. Today, his temperature remains elevated at 38.9°C (102.0°F). He reports a new, dry cough and mild right-sided chest pain that worsens with deep inspiration. Blood pressure is 114/72 mm Hg, pulse is 108/min, and respirations are 20/min. Pulse oximetry shows 94% on room air. Physical examination reveals diminished breath sounds in the right upper lung field. Laboratory studies show a white blood cell count of 0.6 x 10^9/L (ANC 100/mm³). Blood cultures obtained on admission have shown no growth. A high-resolution CT scan of the chest reveals a 2-cm macronodule with a surrounding zone of ground-glass attenuation in the right upper lobe. Which of the following is the most appropriate next step in management?

During a weekend visit with her family, a 62-year-old woman experiences progressively worsening shortness of breath and a 'racing heart' over a 48-hour period. She is evaluated in the acute care clinic, where she frantically states, 'I feel like I am having a severe panic attack; I just cannot catch my breath.' The patient's medical history includes chronic obstructive pulmonary disease (COPD), bipolar disorder (for which she currently takes no medications), and hypothyroidism (managed with levothyroxine). Her most recent echocardiogram from three months prior showed normal left ventricular systolic function with an ejection fraction of $60\%$.

Vital signs are temperature $37.2^{\circ}\text{C}$ ($99.0^{\circ}\text{F}$), blood pressure $136/84 \text{ mmHg}$, pulse $152\text{/min}$, and respirations $26\text{/min}$. Pulse oximetry shows $91\%$ on room air.

Physical examination reveals an irregularly irregular pulse. Lung auscultation demonstrates bilateral basilar crackles and diffuse expiratory wheezes. Trace bilateral lower extremity edema is present.

An electrocardiogram (ECG) reveals an irregularly irregular rhythm with absent P waves, narrow QRS complexes, and a ventricular rate of $152\text{/min}$.

Laboratory testing shows:
- Brain natriuretic peptide (BNP): $720 \text{ pg/mL}$ (Normal: $<100 \text{ pg/mL}$)
- Thyroid-stimulating hormone (TSH): $0.2 \mu\text{U/mL}$ (Normal: $0.4-4.0 \mu\text{U/mL}$)
- Free $T_4$: $0.7 \text{ ng/dL}$ (Normal: $0.8-1.8 \text{ ng/dL}$)

Arterial blood gas on room air reveals:
- $pH = 7.52$
- $pCO_2 = 26 \text{ mmHg}$
- $pO_2 = 62 \text{ mmHg}$
- $HCO_3^- = 20 \text{ mEq/L}$

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

A $68$-year-old man presents to the clinic complaining of an aching, cramping pain in his right calf that consistently occurs after walking approximately two blocks. The pain forces him to stop and is completely relieved after $5$ minutes of rest. His medical history is significant for hypertension, hyperlipidemia, and a $45$-pack-year smoking history. His blood pressure is $138/86$ mmHg and heart rate is $72$/min. Physical examination reveals diminished right dorsalis pedis and posterior tibial pulses. There are no ulcers, rest pain, or signs of critical limb ischemia.

Assuming each intervention is indicated based on the results or failure of the preceding step, arrange the following clinical actions in the most appropriate chronological sequence for the evaluation and management of this patient's condition.

A 24-year-old man is brought to the emergency department due to a 2-day history of generalized weakness, excessive urination, and diffuse abdominal pain. He was diagnosed with type 1 diabetes mellitus 10 years ago and recently missed several doses of his insulin regimen. On physical examination, he appears lethargic and his mucous membranes are dry. Laboratory studies reveal a serum bicarbonate level of 12 mEq/L and an arterial blood pH of 7.28. Which of the following is the expected arterial partial pressure of carbon dioxide ($PaCO_2$) in this patient if appropriate respiratory compensation has occurred?

Match each clinical vignette describing a zoonotic or vector-borne infection with its most appropriate targeted antimicrobial therapy.

Match each clinical presentation with its most characteristic urinalysis finding.

Match each post-renal transplant clinical scenario and associated biopsy finding with the primary pathophysiologic mechanism responsible for the graft dysfunction.

A 45-year-old man is evaluated in the emergency department for severe, constant abdominal pain that began 12 hours ago. He states the pain is located in the upper abdomen and radiates directly to his mid-back. He has had three episodes of non-bilious emesis since the pain started. The patient has a history of alcohol use disorder, consuming approximately six beers daily for the past decade. Vital signs show a temperature of $37.6^\circ\text{C}$ ($99.7^\circ\text{F}$), blood pressure of $142/88\text{ mm Hg}$, heart rate of $112/\text{min}$, and respiratory rate of $18/\text{min}$. Physical examination reveals a diaphoretic man in acute distress. The abdomen is non-distended but exquisitely tender to palpation in the epigastric region; there is no guarding or rebound tenderness. Bowel sounds are sluggish. Laboratory studies reveal:

An abdominal ultrasound demonstrates a normal-appearing gallbladder without cholelithiasis, a normal common bile duct diameter, and obscured views of the pancreas due to overlying bowel gas.

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

Match each classic esophageal disorder with its characteristic finding on esophageal manometry or upper endoscopy.

A 49-year-old man is evaluated in the clinic for persistently elevated blood pressure despite adherence to a three-drug antihypertensive regimen, including a thiazide diuretic. Recent laboratory results reveal a serum potassium level of 2.9 mEq/L (spontaneous hypokalemia). The physician strongly suspects primary hyperaldosteronism. Arrange the steps of the diagnostic workup and management for this condition in the correct sequential order from initial screening to final pre-surgical evaluation.

A medical rapid response team evaluates a 72-year-old female resident of a skilled nursing facility who developed profound lethargy after 3 days of intractable emesis and poor oral intake. Upon transfer to the emergency department, her blood pressure is 82/50 mm Hg, pulse is 124/min, and respirations are 24/min. Physical examination reveals dry mucous membranes, flat neck veins, and delayed capillary refill. Laboratory testing reveals the following:

Which of the following best describes this patient's acid-base status?

A 68-year-old man who was intubated and mechanically ventilated 5 days ago for severe acute respiratory distress syndrome (ARDS) develops a new fever of 38.9°C (102.0°F). His oxygen requirements have increased over the past 24 hours, and thick, purulent secretions are suctioned from the endotracheal tube. A portable chest radiograph reveals a new right lower lobe consolidation. Arrange the following steps in the most appropriate chronological sequence for managing this patient's suspected ventilator-associated pneumonia (VAP).

Match each clinical presentation or patient demographic risk factor with the most likely corresponding glomerular disease.