Internal Medicine

A 72-year-old male is brought to the emergency department experiencing severe, progressive right knee pain and swelling that commenced roughly 12 hours prior. His medical background is significant for hypertension, diet-controlled type 2 diabetes mellitus, and osteoarthritis. Four days ago, he underwent an uncomplicated laparoscopic cholecystectomy and was discharged home the following day. His current temperature is 38.4°C (101.1°F), blood pressure is 135/85 mm Hg, and pulse is 98/min. Physical examination of the right lower extremity demonstrates a visibly swollen, markedly warm, and erythematous knee. The patient shouts in pain with even minimal passive range of motion. Plain radiography of the affected joint reveals medial joint space narrowing, subchondral sclerosis, and a distinct linear calcification within the articular cartilage. Which of the following is the most appropriate next step in management?

A 64-year-old female patient is currently hospitalized for the treatment of acute pyelonephritis. She initially presented to the emergency department three days ago with severe right-sided flank pain, dysuria, and a temperature of $39.2^\circ\text{C}$ ($102.6^\circ\text{F}$). Blood cultures were drawn, and empiric intravenous ceftriaxone was initiated. The admission blood cultures show no growth to date. However, the urine culture obtained prior to antibiotic administration has grown $>10^5$ colony-forming units/mL of *Escherichia coli*. The susceptibility report is as follows:

Today, the patient reports that her flank pain has nearly resolved. Her current temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $122/78 \text{ mmHg}$, and heart rate is $78/\text{min}$. She is tolerating a regular diet without nausea.

Based on the culture results and the patient's clinical progress, which of the following is the most appropriate next step in the pharmacologic management of this patient?

Match each clinical infectious disease vignette with its most appropriate targeted pharmacotherapy or first-line treatment regimen.

A 45-year-old man presents to the clinic complaining of profound fatigue, a 6-kg (13.2-lb) weight loss, and generalized weakness over the past 4 months. He also notes decreased libido and occasional dizziness when standing. Two years ago, he sustained a severe traumatic brain injury in a motor vehicle collision that required a 3-week stay in the intensive care unit. His blood pressure is 102/62 mm Hg while supine and 84/52 mm Hg upon standing. Heart rate is 86/min. Physical examination reveals loss of axillary and pubic hair, and delayed relaxation of deep tendon reflexes. Laboratory studies show:

* Sodium: $131 \text{ mEq/L}$
* Potassium: $4.0 \text{ mEq/L}$
* Thyroid-stimulating hormone (TSH): $2.2 \text{ } \mu\text{U/mL}$ (Normal: $0.4–4.0 \text{ } \mu\text{U/mL}$)
* Free T4: $0.5 \text{ ng/dL}$ (Normal: $0.9–1.7 \text{ ng/dL}$)

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

Review the clinical vignettes below, which present various mechanisms of renal and systemic acid-base derangements. Which classic arterial blood gas and serum chemistry profile is most strongly associated with each patient's presentation?

Match each of the following patient laboratory profiles to the most likely underlying pathophysiologic mechanism.

(Reference ranges: Serum Calcium: 8.4-10.2 mg/dL; Intact PTH: 10-65 pg/mL; Phosphorus: 2.5-4.5 mg/dL; 24-hour urine calcium: 100-300 mg/day).

An otherwise healthy $26$-year-old male is evaluated in the outpatient clinic due to a $4$-day history of a swollen, painful, and warm right knee. He also reports recent onset of left heel pain that worsens with walking. For the past week, he has experienced bilateral eye redness and a "gritty" sensation. Three weeks prior to this visit, the patient had a self-limited episode of fever, abdominal cramps, and watery diarrhea that resolved after a few days. His current temperature is $37.4^\circ\text{C}$ ($99.3^\circ\text{F}$), blood pressure is $122/78$ mmHg, and pulse is $86$/min. Physical examination shows a large effusion in the right knee with restricted range of motion secondary to pain. There is marked tenderness at the insertion of the left Achilles tendon. Bilateral conjunctival injection is noted without purulent discharge. Arthrocentesis of the right knee yields $40$ mL of cloudy yellow fluid. Synovial fluid analysis reveals a leukocyte count of $35,000/\text{mm}^3$ with $80\%$ neutrophils. Gram stain shows no organisms, and polarized light microscopy demonstrates no crystals. Which of the following is the most appropriate next step in the management of this patient?

A clinical quality committee is reviewing antimicrobial prescribing practices within the gastroenterology and hepatology department. Match the following patient scenarios with the most appropriate, guideline-concordant initial pharmacological management to promote effective care and antimicrobial stewardship.

A 66-year-old retired mechanic is brought to the clinic by his daughter after experiencing difficulty walking over the past 24 hours. He reports a two-week history of dull, continuous pain in his mid-thoracic region that worsens when he lies flat in bed. His past medical history is significant for non-small cell lung cancer treated with radiation and chemotherapy two years ago. On neurologic examination, he demonstrates 3/5 strength in the bilateral lower extremities, diminished sensation to pinprick below the umbilicus, and symmetric hyperreflexia at the patellae and ankles. Rectal examination reveals decreased sphincter tone. Vital signs are within normal limits except for a temperature of 37.8°C (100.0°F). Laboratory results reveal a normal leukocyte count and a serum calcium level of 9.2 mg/dL. Which of the following is the most appropriate initial step in the management of this patient?

A 45-year-old woman is brought to the emergency department due to progressive muscle weakness. Over the past week, she has had difficulty rising from a chair and climbing stairs. She has a 5-year history of primary Sjögren syndrome, for which she uses artificial tears and saliva substitutes. Vital signs are within normal limits. Physical examination shows symmetric 3/5 muscle strength in the proximal upper and lower extremities, with decreased deep tendon reflexes.

Laboratory studies are obtained:

Which of the following best explains this patient's clinical presentation and laboratory findings?

A $71$-year-old man is evaluated in the emergency department for severe, progressive shortness of breath over the past two days. He has a complex medical history that includes ischemic cardiomyopathy and chronic obstructive pulmonary disease. On physical examination, he is tachypneic and sitting upright in bed. Auscultation of the lungs reveals diffuse bilateral expiratory wheezing with faint crackles at the bases. To help distinguish between a pulmonary and a cardiovascular etiology for his acute presentation, the physician orders a rapid serum laboratory test that measures a specific endogenous polypeptide. The test results show a markedly elevated concentration of this polypeptide, supporting acute decompensated heart failure as the primary cause of his symptoms.

What is the primary physiologic stimulus for the secretion of the polypeptide measured in this patient?

A 62-year-old man is brought to the emergency department via ambulance due to the sudden onset of severe, tearing chest pain that radiates to his interscapular region. His blood pressure is 195/115 mm Hg in the right arm and 170/100 mm Hg in the left arm. Heart rate is 110/min. Physical examination reveals a new diastolic decrescendo murmur at the right upper sternal border. Arrange the following steps in the most appropriate chronological order for the initial evaluation and management of this patient.

A 34-year-old woman comes to the clinic reporting a 6-month history of severe fatigue, a 5-kg (11-lb) weight gain, and generalized weakness. She also reports cold intolerance and irregular menstrual periods, with her last menses occurring 4 months ago. She has no significant past medical history and takes no medications. Blood pressure is 100/60 mmHg and pulse is 55/min. Physical examination shows a tired-appearing woman with dry skin. Deep tendon reflexes exhibit a delayed relaxation phase. Laboratory results are as follows:

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

A $48$-year-old male arrives at the emergency department reporting an abrupt onset of severe, constant epigastric pain that radiates to his back. The pain began $4$ hours ago after he consumed a heavy meal. He has experienced two episodes of nonbilious emesis since symptom onset. He has a history of hyperlipidemia and takes rosuvastatin. His temperature is $37.9^\circ\text{C}$ ($100.2^\circ\text{F}$), heart rate is $115/\text{min}$, blood pressure is $128/82\text{ mmHg}$, and respiratory rate is $18/\text{min}$. Cardiopulmonary examination is unremarkable. Abdominal examination reveals decreased bowel sounds and significant epigastric tenderness without rebound or guarding.

Laboratory studies show:

A right upper quadrant ultrasound reveals multiple mobile gallstones within the gallbladder. The common bile duct measures $4\text{ mm}$ in diameter, and there is no intrahepatic biliary dilation.

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

An emergency department evaluation is requested for a 58-year-old male presenting with progressively worsening shortness of breath and a cough producing frothy sputum over the past 48 hours. His medical history is significant for a 30-pack-year smoking habit and type 2 diabetes mellitus complicated by diabetic nephropathy. Upon arrival, he is in moderate respiratory distress.

Vital signs reveal a blood pressure of $185/110 \text{ mm Hg}$, pulse of $112/\text{min}$, and respiratory rate of $28/\text{min}$. Oxygen saturation is 88% on room air. Pulmonary auscultation reveals bilateral crackles extending to the mid-lung fields along with diffuse expiratory wheezing. Examination of the lower extremities shows 2+ bilateral pitting edema.

Laboratory evaluation reveals the following:
Serum sodium: $138 \text{ mEq/L}$
Serum potassium: $5.9 \text{ mEq/L}$
Serum chloride: $102 \text{ mEq/L}$
Serum bicarbonate: $12 \text{ mEq/L}$
Blood urea nitrogen: $92 \text{ mg/dL}$
Serum creatinine: $7.4 \text{ mg/dL}$

Arterial blood gas (room air):
pH: $7.22$
$p\text{CO}_2$: $36 \text{ mm Hg}$
$p\text{O}_2$: $58 \text{ mm Hg}$

Based on the clinical and laboratory findings, which of the following best describes this patient's current acid-base disorder and the primary cause of his respiratory distress?

A 28-year-old man presents to the emergency department with a 3-week history of daily spiking fevers, reaching up to 39.6°C (103.3°F), typically occurring in the late afternoon. He reports a severe sore throat, profound fatigue, and worsening pain and swelling in his bilateral wrists and knees. He notes a faint, salmon-colored rash on his trunk that seems to appear only during his febrile episodes and resolves when his temperature normalizes. He had an uncomplicated appendectomy 4 weeks ago. He is also stressed because his employer is demanding his specific medical diagnosis to approve his prolonged sick leave.

Vital signs show a temperature of 39.5°C (103.1°F), blood pressure of 120/78 mm Hg, heart rate of 110/min, and respiratory rate of 16/min. Physical examination reveals swollen, tender wrists and a macular erythematous rash on the chest. The lungs are clear to auscultation. Laboratory studies reveal:

Rheumatoid factor and antinuclear antibody (ANA) tests are negative. Blood cultures drawn 3 days ago in the outpatient clinic are sterile. Which of the following is the most appropriate next step in the management of this patient?

For each of the following hospitalized patients presenting with severe, confirmed, or highly suspected infections, select the most appropriate definitive or targeted empiric intravenous antimicrobial therapy from the options provided.

Match each patient's clinical presentation with the autoantibody most specific to or characteristic of their underlying diagnosis.

A 55-year-old man presents to the clinic with a 4-month history of worsening fatigue, generalized weakness, and cold intolerance. He also reports a significant decrease in libido and difficulty achieving erections over the same period. The patient occasionally experiences mild, dull headaches but denies any changes in his vision. His blood pressure is $112/72 \text{ mm Hg}$ and pulse is $56/\text{min}$. Physical examination is notable for dry skin, sparse body hair, and delayed relaxation of the deep tendon reflexes. Visual field testing is full to confrontation. Laboratory evaluation is performed, with the following results:

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

A 55-year-old man presents to the emergency department with a 4-day history of profuse watery diarrhea. He reports orthostatic dizziness, generalized weakness, and a significantly reduced urine output over the past 24 hours. He has no significant past medical history and takes no medications. Vital signs show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure of $88/55\text{ mm Hg}$, and a heart rate of $122/\text{min}$. Physical examination reveals dry mucous membranes, decreased skin turgor, and flat jugular veins.

Laboratory studies are as follows:

Serum
Sodium: $140\text{ mEq/L}$
Potassium: $3.2\text{ mEq/L}$
Chloride: $110\text{ mEq/L}$
Bicarbonate: $18\text{ mEq/L}$
Blood urea nitrogen (BUN): $60\text{ mg/dL}$
Creatinine: $2.5\text{ mg/dL}$

Urine
Sodium: $14\text{ mEq/L}$
Creatinine: $50\text{ mg/dL}$

What is this patient's fractional excretion of sodium ($Fe_{Na}$) in percentage?