Internal Medicine

A 56-year-old man is brought to the emergency department by paramedics after being found unresponsive in an alley. The paramedics administered intravenous naloxone en route, which resulted in a transient increase in his respiratory rate, but he remains obtunded upon arrival. The patient is unhoused and has a history of severe alcohol use disorder. His temperature is 36.1°C (97.0°F), blood pressure is 105/65 mm Hg, pulse is 92/min, and respirations are 8/min and shallow. Pulse oximetry shows 88% on room air.

Laboratory studies show the following:
Serum sodium: 142 mEq/L
Serum potassium: 4.8 mEq/L
Serum chloride: 100 mEq/L
Serum bicarbonate: 12 mEq/L
Blood urea nitrogen: 32 mg/dL
Serum creatinine: 1.7 mg/dL

Arterial blood gas analysis on room air:
pH: 7.18
$pCO_2$: 50 mm Hg
$pO_2$: 60 mm Hg

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

A $28$-year-old man comes to the clinic for a routine wellness examination. He has no significant past medical history and takes no medications. He has no symptoms of fatigue, bone pain, abdominal pain, or polyuria. Family history is notable for mild hypercalcemia in his father, who has never required medical or surgical intervention. Vital signs are within normal limits. Physical examination is unremarkable. Laboratory testing reveals the following:

Serum calcium: $11.3\ \text{mg/dL}$ (normal: $8.4\text{--}10.2\ \text{mg/dL}$)
Serum phosphorus: $2.8\ \text{mg/dL}$ (normal: $2.7\text{--}4.5\ \text{mg/dL}$)
Serum creatinine: $0.9\ \text{mg/dL}$
Serum intact parathyroid hormone: $58\ \text{pg/mL}$ (normal: $10\text{--}65\ \text{pg/mL}$)
Serum 25-hydroxyvitamin D: $34\ \text{ng/mL}$ (normal: $20\text{--}50\ \text{ng/mL}$)

Based on the information provided, which of the following is the most appropriate next step in the evaluation of this patient?

A 32-year-old woman presents to the ambulatory care clinic reporting four days of frequent, large-volume, watery stools after returning from an international trip. During the interview, she is noticeably distressed and pacing the room. She states she is terrified of acquiring a severe parasitic infection and has been breathing rapidly for the past hour. Physical examination reveals dry mucous membranes and hyperactive bowel sounds. Vital signs include a heart rate of $112/\text{min}$, blood pressure of $105/65\ \text{mm Hg}$, and respiratory rate of $30/\text{min}$. Laboratory results are as follows:

Serum sodium: $138\ \text{mEq/L}$
Serum potassium: $3.4\ \text{mEq/L}$
Serum chloride: $116\ \text{mEq/L}$
Serum bicarbonate: $12\ \text{mEq/L}$

Arterial blood gas (room air):
pH: $7.38$
$pCO_2$: $21\ \text{mm Hg}$

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

A 64-year-old woman is brought to the emergency department by emergency medical services due to severe, worsening shortness of breath that began 24 hours ago. The patient has a history of ischemic cardiomyopathy with a left ventricular ejection fraction of $30\%$, hypertension, type 2 diabetes mellitus, and chronic obstructive pulmonary disease (GOLD stage III). Her temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $170/95\text{ mm Hg}$, pulse is $118/\text{min}$, and respirations are $28/\text{min}$. Pulse oximetry shows $86\%$ on room air. She appears in moderate respiratory distress and is using accessory muscles of respiration. Lung auscultation reveals prolonged expiration, diffuse expiratory wheezing, and bilateral crackles at the lung bases. Cardiovascular examination shows distant heart sounds, a normal S1 and S2, and a prominent S3 gallop. The jugular venous pressure is estimated at $13\text{ cm H}_2\text{O}$. There is $2+$ bilateral lower extremity pitting edema.

Laboratory studies show:

Chest radiograph reveals cardiomegaly, bilateral pleural effusions, and cephalization of the pulmonary vasculature. Which of the following is the most appropriate next step in management?

During an evening shift in the emergency department, a $71$-year-old woman is evaluated for a three-day history of progressively worsening dyspnea and increased production of thick, yellowish-green sputum. She has a history of severe chronic obstructive pulmonary disease (COPD), essential hypertension, and osteoarthritis. Her current maintenance medications include a long-acting muscarinic antagonist, a long-acting beta-agonist, and as-needed albuterol.

Vital signs reveal a temperature of $37.6^\circ C$ ($99.7^\circ F$), heart rate of $118/min$, respiratory rate of $28/min$, and blood pressure of $142/85 \text{ mm Hg}$. Oxygen saturation is $86\%$ on room air.

On physical examination, she is in acute respiratory distress and is utilizing accessory muscles of respiration. Jugular venous pressure is visibly elevated at $10 \text{ cm H}_2\text{O}$. Lung auscultation demonstrates prolonged expiration, diffuse expiratory wheezing, and faint bibasilar crackles. She has $2+$ pitting edema in both lower extremities.

Laboratory studies are notable for:
Leukocyte count: $12,500/\mu L$
Brain natriuretic peptide (BNP): $210 \text{ pg/mL}$ (normal $<100 \text{ pg/mL}$)
Thyroid-stimulating hormone (TSH): $1.4 \mu\text{U/mL}$ (normal $0.5-5.0 \mu\text{U/mL}$)
Free T4: $0.5 \text{ ng/dL}$ (normal $0.9-1.7 \text{ ng/dL}$)

Arterial blood gas on room air:
pH: $7.27$
PaO2: $56 \text{ mm Hg}$
PaCO2: $66 \text{ mm Hg}$
HCO3: $29 \text{ mEq/L}$

A chest radiograph shows hyperinflation with flattened diaphragms and enlarged central pulmonary arteries, without focal consolidation.

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

A 32-year-old woman with a history of systemic lupus erythematosus presents to the clinic with new-onset bilateral lower extremity edema, worsening fatigue, and newly elevated blood pressure of 150/95 mmHg. Recent laboratory studies show worsening normocytic anemia, hypocomplementemia (decreased C3 and C4), and an increasing serum creatinine level from 0.8 mg/dL to 1.6 mg/dL. Arrange the following clinical steps in the most appropriate sequential order for the standard diagnosis and management of this patient's suspected complication.

A 74-year-old man residing in a skilled nursing facility is evaluated on hospital day $3$ for a complicated urinary tract infection. He was initially brought to the emergency department for altered mental status and a new fever. On admission, his temperature was $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$), and his long-term indwelling urinary catheter was found to be obstructed with purulent sediment. The catheter was promptly removed, and he was started empirically on intravenous vancomycin and piperacillin-tazobactam. Today, the patient is afebrile, his mental status has returned to baseline, and he is tolerating an oral diet. Blood cultures obtained on admission show no growth. A urine culture obtained via straight catheterization prior to antibiotic initiation grows $>100,000\text{ CFU/mL}$ of Escherichia coli. Susceptibility testing reveals the organism is susceptible to ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole, but resistant to ampicillin. Which of the following is the most appropriate next step in management?

Match each patient's clinical presentation with its corresponding primary structural or hemodynamic finding.

A 68-year-old man is brought to the emergency department by his family due to confusion, a severe headache, and high fever that began 24 hours ago. He has a history of type 2 diabetes mellitus and hypertension. His temperature is 39.2°C (102.6°F), blood pressure is 112/74 mm Hg, heart rate is 115/min, and respiratory rate is 22/min. Physical examination shows marked nuchal rigidity. Neurologic examination reveals lethargy and a mild left-sided hemiparesis. The physician suspects bacterial meningitis. Arrange the following management steps in the most appropriate chronological order for this patient.

During physical examination of the cardiovascular system, palpation of the arterial pulse can provide critical clues regarding underlying hemodynamics. Match the following characteristic arterial pulse abnormalities with the cardiovascular condition they most classically represent.

A 68-year-old man with a history of severe chronic obstructive pulmonary disease (COPD) is brought to the emergency department by his wife due to worsening shortness of breath, profound fatigue, and confusion. According to the wife, the patient has had severe, large-volume, watery diarrhea for the past four days. His temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $100/60$ mm Hg, pulse is $112$/min, and respiratory rate is $24$/min. Physical examination reveals dry mucous membranes, decreased skin turgor, and diminished breath sounds bilaterally with a prolonged expiratory phase.

Laboratory results are as follows:

Arterial blood gas analysis on room air:

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

Match each classic clinical presentation to the most likely acute gastrointestinal diagnosis.

Paramedics bring a distressed gentleman in his late sixties to the emergency department. He reports severe, unremitting abdominal pain that began $48$ hours ago as intermittent cramps but has now become constant and sharply localized. His last bowel movement was three days ago, and he has vomited dark, foul-smelling fluid multiple times since yesterday. His surgical history is notable for a ruptured appendix requiring an open appendectomy in his twenties.

On evaluation, his temperature is $38.8^\circ\text{C}$ ($101.8^\circ\text{F}$), heart rate is $122/\text{min}$, blood pressure is $88/54\text{ mmHg}$, and respiratory rate is $22/\text{min}$. The abdomen is tense, visibly distended, and exquisitely tender to light palpation across all quadrants, with involuntary guarding. Auscultation reveals a silent abdomen. Laboratory analysis demonstrates a leukocyte count of $19,500/\text{mm}^3$ and a serum lactate of $4.5\text{ mmol/L}$. Upright abdominal radiography displays multiple dilated loops of small bowel with air-fluid levels and a complete absence of gas in the rectum.

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

A 59-year-old woman suddenly collapses while walking in the hospital corridor. A rapid response team arrives immediately. The patient is completely unresponsive, apneic, and has no palpable carotid pulse. The team brings a crash cart with a manual defibrillator, and cardiac monitoring reveals coarse ventricular fibrillation. Arrange the following resuscitative interventions in the correct chronological sequence according to current Advanced Cardiac Life Support (ACLS) guidelines for this rhythm.

Match each clinical presentation of chronic liver disease to the most appropriate next step in management or definitive therapy.

A 62-year-old man with a history of ischemic cardiomyopathy suddenly collapses while walking in the hospital corridor. A rapid response team arrives immediately. The patient is unresponsive, apneic, and has no palpable carotid pulse. High-quality chest compressions are initiated, and a defibrillator is attached. The monitor displays coarse ventricular fibrillation.

Assuming the patient remains in refractory ventricular fibrillation throughout the resuscitation, arrange the following advanced cardiac life support (ACLS) interventions in the correct chronological sequence.

Match each clinical presentation or hemodynamic profile in a patient with advanced liver cirrhosis to the most appropriate systemic complication.

Match each characteristic arterial pulse finding on physical examination with its most likely underlying cardiovascular pathology.

Match each of the following serum laboratory profiles with the most likely underlying clinical diagnosis. (Reference ranges: Calcium $8.4-10.2\text{ mg/dL}$, Phosphorus $2.7-4.5\text{ mg/dL}$, Intact PTH $15-65\text{ pg/mL}$)

Match the following cardiac arrhythmias and conduction disorders with their characteristic electrocardiogram (ECG) findings.