Internal Medicine

During morning rounds in the medical intensive care unit, a physician evaluates a patient admitted for severe hypovolemia secondary to intractable diarrhea.

The patient, a $55$-year-old male, reports four days of unremitting watery stools. Intravenous fluid resuscitation is planned but has not yet been initiated. Vital signs show a blood pressure of $90/60\text{ mm Hg}$ and a heart rate of $110/\text{min}$. Physical examination is notable for poor skin turgor, delayed capillary refill, and dry oral mucosa. Laboratory analysis of blood and urine samples obtained simultaneously reveals the following values:

Based on these findings, what is the patient's calculated fractional excretion of sodium (in percent)?

A physician is reviewing several cases of suspected infective endocarditis. The causative microorganisms often have distinct clinical associations based on patient demographics and antecedent procedures. For each patient presentation described below, identify the most probable responsible pathogen.

An $82$-year-old man arrives at the emergency department accompanied by his daughter due to a $3$-day history of progressively worsening difficulty breathing. He states he cannot sleep lying flat and requires three pillows at night. Medical history is significant for coronary artery disease with a previous myocardial infarction, type 2 diabetes mellitus, and severe chronic obstructive pulmonary disease (COPD). His current medications include lisinopril, metoprolol succinate, and a daily tiotropium inhaler.

Vital signs are:
Temperature: $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$)
Blood pressure: $158/92\text{ mm Hg}$
Pulse: $115/\text{min}$
Respirations: $28/\text{min}$
Oxygen saturation: $85\%$ on room air

Physical examination shows a patient in acute respiratory distress using accessory muscles. The jugular venous pressure is distended to $12\text{ cm H}_2\text{O}$. Auscultation of the chest reveals diminished breath sounds with prolonged expiration, diffuse expiratory wheezes, and dullness to percussion at the lung bases. Cardiac examination reveals a regular tachycardia, a normal $S_1$ and $S_2$, and an extra low-frequency heart sound occurring just after $S_2$.

Laboratory and arterial blood gas (room air) results are as follows:

A portable chest radiograph displays an enlarged cardiac silhouette, perihilar alveolar opacities, and bilateral blunting of the costophrenic angles. The patient is placed on noninvasive positive-pressure ventilation.

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

A 28-year-old woman comes to the clinic for evaluation of an elevated calcium level discovered during a routine life insurance medical examination. The patient is completely asymptomatic and reports no fatigue, weakness, abdominal pain, constipation, or bone pain. She exercises regularly and takes no medications or over-the-counter supplements. Her family history is notable for her mother having "mildly elevated calcium" that persisted despite undergoing a parathyroidectomy several years ago. Vital signs and physical examination are unremarkable.

Laboratory studies show:
Serum calcium: $11.3\text{ mg/dL}$
Albumin: $4.0\text{ g/dL}$
Serum phosphorus: $2.6\text{ mg/dL}$
Creatinine: $0.8\text{ mg/dL}$
Intact parathyroid hormone: $62\text{ pg/mL}$ (normal: $10-65\text{ pg/mL}$)

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

A 58-year-old man is evaluated in the emergency department for sudden-onset, severe, "tearing" chest pain that radiates to his back. The pain began one hour ago while he was lifting heavy boxes. He has a history of poorly controlled hypertension. His temperature is 37.2°C (99.0°F), pulse is 112/min, and respirations are 22/min. Blood pressure is 215/115 mm Hg in the right arm and 175/95 mm Hg in the left arm. Physical examination reveals a new early diastolic decrescendo murmur heard best at the right upper sternal border. An electrocardiogram shows sinus tachycardia and left ventricular hypertrophy without acute ischemic changes. Chest radiography reveals a widened mediastinum.

Arrange the following patient management steps in the most appropriate chronological order.

A $58$-year-old man is brought to the emergency department complaining of sudden-onset, severe, "tearing" chest pain that radiates to his back. He appears diaphoretic and is in acute distress. Vital signs show a blood pressure of $210/115$ mmHg in the right arm and $175/95$ mmHg in the left arm, a heart rate of $112$/min, and a respiratory rate of $20$/min. An electrocardiogram shows sinus tachycardia with no ST-segment or T-wave abnormalities. A portable chest x-ray reveals a widened mediastinum. Arrange the following steps in the most appropriate chronological order for the acute management of this patient.

During a routine occupational health evaluation, a 49-year-old construction worker is found to have a blood pressure of $192/115\text{ mm Hg}$. When questioned, he reports experiencing unprovoked spells of intense diaphoresis, forceful heart palpitations, and throbbing headaches over the past three months. His physician strongly suspects a catecholamine-secreting adrenal medullary tumor.

Arrange the following diagnostic and therapeutic interventions in the correct sequential order for managing this patient's suspected condition.

A $64$-year-old woman is brought to the triage desk by her family due to extreme lightheadedness and a progressive inability to catch her breath over the past three days. She has a medical history significant for severe rheumatoid arthritis and chronic obstructive pulmonary disease. Two weeks ago, she experienced a self-limiting febrile viral illness. On examination, the patient appears visibly distressed and diaphoretic. Vital signs show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), heart rate of $118\text{/min}$, respiratory rate of $24\text{/min}$, and blood pressure of $86/60\text{ mmHg}$. During normal inspiration, her systolic blood pressure decreases by $18\text{ mmHg}$. Jugular venous distention is prominent up to the angle of the mandible while she sits upright. Pulmonary auscultation reveals globally distant breath sounds but no crackles or active wheezing. Cardiac auscultation is limited by an increased anterior-posterior chest diameter, and no murmurs are appreciated. An electrocardiogram demonstrates a regular tachycardia with low-voltage QRS complexes in the limb leads and shifting electrical axes. Which of the following is the most appropriate next step in management?

An emergency department physician is evaluating a 63-year-old man who presents with four days of progressively worsening shortness of breath. The patient reports a noticeable increase in both the volume and purulence of his daily sputum. His medical history is significant for severe tobacco use disorder, chronic obstructive pulmonary disease, and mild ischemic cardiomyopathy. His current home medications include inhaled tiotropium, inhaled fluticasone-vilanterol, and low-dose carvedilol.

Upon arrival, his temperature is $37.6^\circ\text{C}$ ($99.7^\circ\text{F}$), blood pressure is $148/92\text{ mmHg}$, pulse is $108\text{/min}$, and respiratory rate is $26\text{/min}$. Oxygen saturation is $85\%$ on ambient air.

Physical examination reveals a patient in moderate respiratory distress, sitting in a tripod position with prominent accessory muscle use. Auscultation of the lungs demonstrates a significantly prolonged expiratory phase with diffuse, bilateral expiratory wheezing. Jugular venous pressure is estimated at $6\text{ cm H}_2\text{O}$, and there is no peripheral edema.

Arterial blood gas analysis obtained on room air shows:
$\text{pH}$: $7.26$
$\text{PaCO}_2$: $66\text{ mmHg}$
$\text{PaO}_2$: $54\text{ mmHg}$
$\text{HCO}_3^-$: $29\text{ mEq/L}$

A portable chest radiograph displays hyperinflated lung fields with flattened diaphragms, without focal consolidations, pleural effusions, or cardiomegaly.

Which of the following interventions are appropriate for the acute management of this patient? (Select all that apply)

A 58-year-old man with a history of alcohol-associated cirrhosis and refractory ascites is hospitalized due to an acute rise in serum creatinine. Over the past week, his weight has increased by $4$ kg ($8.8$ lbs), and his urine output has decreased. His home medications include furosemide, spironolactone, and nadolol. On admission, his temperature is $37.1^\circ$ C ($98.8^\circ$ F), blood pressure is $90/60$ mm Hg, and pulse is $98$/min. Physical examination reveals scleral icterus, spider angiomas, and a markedly distended abdomen with shifting dullness. There is no abdominal tenderness, rebound, or guarding. Lungs are clear to auscultation. Laboratory studies on admission reveal:

Sodium: $131$ mEq/L
Potassium: $4.2$ mEq/L
Bicarbonate: $22$ mEq/L
BUN: $45$ mg/dL
Creatinine: $2.8$ mg/dL (baseline $1.1$ mg/dL one month ago)
Total bilirubin: $3.5$ mg/dL

Diagnostic paracentesis yields clear, yellow fluid with a leukocyte count of $120$/mm $^3$ ($10\%$ neutrophils) and negative Gram stain. All diuretics and nadolol are discontinued. He is given intravenous albumin at a dose of $1$ g/kg/day. Forty-eight hours later, his blood pressure is $92/60$ mm Hg and pulse is $95$/min. Repeat laboratory studies show a serum creatinine of $3.1$ mg/dL. Urinalysis reveals no red blood cells, white blood cells, or casts. Urine sodium concentration is $8$ mEq/L. Renal ultrasound shows normal kidney size with no hydronephrosis. Which of the following is the most appropriate next step in management?

Match the following structural heart diseases with their characteristic dynamic auscultation findings elicited during physical maneuvers.

A 21-year-old man with a history of type 1 diabetes mellitus is brought to the emergency department due to altered mental status, nausea, and abdominal pain for the past 24 hours. He recently had a respiratory tract infection and missed several doses of insulin due to poor appetite. On physical examination, his temperature is 37.4°C (99.3°F), blood pressure is 90/60 mm Hg, pulse is 118/min, and respiratory rate is 28/min with deep, rapid breathing. His mucous membranes are extremely dry. Laboratory studies reveal:

Serum glucose: $580\text{ mg/dL}$
Serum sodium: $132\text{ mEq/L}$
Serum potassium: $4.9\text{ mEq/L}$
Serum bicarbonate: $11\text{ mEq/L}$
Arterial blood gas: pH $7.18$
Serum ketones: Positive

Arrange the following management steps in the most appropriate chronological sequence for the acute and subacute treatment of this patient's condition.

A 19-year-old woman is brought to the emergency department by her roommate due to nausea, vomiting, and "ringing" in her ears. The roommate reports that the patient was distraught after a severe argument and ingested an unknown quantity of an over-the-counter pain medication approximately 5 hours ago. On physical examination, her temperature is 37.8°C (100.0°F), blood pressure is 112/68 mm Hg, pulse is 115/min, and respirations are 32/min. She appears agitated and is breathing deeply and rapidly. Her lungs are clear to auscultation bilaterally.

Laboratory studies show:
* Serum sodium: $139$ mEq/L
* Serum potassium: $3.7$ mEq/L
* Serum chloride: $103$ mEq/L
* Serum bicarbonate: $14$ mEq/L
* Blood urea nitrogen: $16$ mg/dL
* Serum creatinine: $0.9$ mg/dL

Arterial blood gas analysis on room air reveals:
* pH: $7.46$
* $PaCO_2$: $20$ mm Hg
* $PaO_2$: $105$ mm Hg
* $HCO_3^-$: $14$ mEq/L

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

Two weeks after completing a course of oral moxifloxacin for a community-acquired lower respiratory tract infection, a $71$-year-old male presents to the urgent care clinic complaining of profuse, watery diarrhea. He reports having up to $8$ loose bowel movements daily, accompanied by diffuse abdominal cramps and subjective fever. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), pulse is $102/\text{min}$, and blood pressure is $114/72\text{ mmHg}$. Physical examination reveals a mildly distended abdomen with generalized tenderness to palpation, but no guarding or rigidity. Laboratory evaluation shows a leukocyte count of $18,500/\text{mm}^3$ and a serum creatinine level of $1.4\text{ mg/dL}$ (baseline $1.0\text{ mg/dL}$). Enzyme immunoassay of the stool is positive for glutamate dehydrogenase antigen and *Clostridioides difficile* toxins A and B. Which of the following is the most appropriate pharmacotherapy for this patient's current condition?

A 31-year-old male is admitted to the general medical ward for evaluation of severe right arm pain and persistent fevers. He reports a history of injection drug use. His vital signs on admission include a temperature of 39.1°C (102.4°F), blood pressure of 112/70 mm Hg, and a heart rate of 115/min. Physical examination of the right upper extremity reveals a 4-cm area of fluctuance with overlying warmth and marked erythema. Initial blood cultures are obtained, and he is empirically commenced on intravenous vancomycin and piperacillin-tazobactam. An echocardiogram shows structurally normal valves with no vegetations. Over the subsequent two days, the patient defervesces and the localized arm erythema improves. The laboratory reports that the admission blood cultures are positive in all bottles for Staphylococcus aureus. Antimicrobial susceptibility testing demonstrates resistance to penicillin but susceptibility to oxacillin, cefazolin, daptomycin, and vancomycin. Which of the following is the most appropriate modification to his antimicrobial therapy?

Evaluate the following diagnostic test patterns evaluating the hypothalamic-pituitary-adrenal (HPA) axis and pair each biochemical profile with the most likely underlying etiology.

A 62-year-old man is receiving positive-pressure mechanical ventilation in the intensive care unit for acute respiratory distress syndrome. Suddenly, the ventilator alarms for high peak airway pressures. His blood pressure drops to 65/40 mm Hg, and his heart rate increases to 142/min. Oxygen saturation drops to 80%. Physical examination reveals absent breath sounds and hyperresonance to percussion over the right hemithorax, with tracheal deviation to the left.

Arrange the following steps in the most appropriate chronological order for the management of this patient's acute complication.

A series of patients undergo evaluation for various nephritic and nephrotic syndromes. Based on the underlying pathophysiologic mechanisms, match each specific glomerular disease with its characteristic defining renal biopsy finding.

A $56$-year-old man comes to the clinic reporting profound fatigue, generalized weakness, and feeling cold all the time for the past $3$ weeks. He has a history of metastatic melanoma and has been receiving ipilimumab therapy for the past $4$ months. He reports poor appetite but has not lost significant weight. Blood pressure is $98/60\text{ mm Hg}$ and pulse is $58\text{/min}$ with no orthostatic changes. Physical examination shows pale skin without hyperpigmentation and delayed relaxation of the deep tendon reflexes. Laboratory studies show the following:

Serum sodium: $138\text{ mEq/L}$
Serum potassium: $4.1\text{ mEq/L}$
Serum thyroid-stimulating hormone (TSH): $1.1\text{ mU/L}$ (normal: $0.4\text{--}4.0\text{ mU/L}$)
Serum free thyroxine (T4): $0.5\text{ ng/dL}$ (normal: $0.8\text{--}1.8\text{ ng/dL}$)

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

Paramedics bring a 24-year-old woman to the resuscitation bay due to an intractable respiratory crisis. The patient's roommate reports that she has a long-standing history of asthma and has been using her rescue inhaler excessively over the past three hours with no improvement. On initial assessment, the patient is visibly exhausted, diaphoretic, and exhibits a decreased level of consciousness. Vital signs are temperature 37.2°C (99.0°F), pulse 135/min, blood pressure 110/65 mm Hg, and respirations 34/min. Pulse oximetry is 86% on room air. Auscultation of the lungs reveals markedly decreased breath sounds bilaterally with no audible wheezing.

An arterial blood gas analysis on room air reveals the following:

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