Internal Medicine

Match each patient's clinical presentation of chronic diarrhea to the underlying pathophysiologic mechanism that best explains their symptoms.

A 58-year-old woman is evaluated in the emergency department for a 3-day history of progressively worsening left lower quadrant abdominal pain, accompanied by fever and chills. She has a history of chronic constipation but has had no previous similar episodes of abdominal pain. Her temperature is $38.6^\circ\text{C}$ ($101.5^\circ\text{F}$), blood pressure is $132/82\text{ mm Hg}$, pulse is $98/\text{min}$, and respirations are $16/\text{min}$. Physical examination reveals focal tenderness in the left lower quadrant with voluntary guarding. There is no rebound tenderness or abdominal rigidity. Bowel sounds are hypoactive. Laboratory evaluation shows a leukocyte count of $16,500/\text{mm}^3$ with $85\%$ neutrophils. An abdominal CT scan with oral and intravenous contrast demonstrates mural thickening of the sigmoid colon with prominent diverticula, pericolic fat stranding, and a $4.5\text{-cm}$ adjacent rim-enhancing fluid collection.

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

During morning rounds, the care team reviews the progress of a 34-year-old female patient admitted two days ago with complicated urinary tract infection.

Vital signs at admission were:
- Temperature: 39.4°C (102.9°F)
- Blood pressure: 92/58 mm Hg
- Pulse: 115/min

She received intravenous fluid resuscitation and empiric therapy with intravenous piperacillin-tazobactam. Today, the patient reports feeling much better, noting her flank pain has nearly resolved and she is eating a regular diet. Current vital signs show a temperature of 37.0°C (98.6°F), blood pressure of 116/74 mm Hg, and a pulse of 78/min.

The microbiology laboratory updates the results from the admission urine and blood cultures. Both are positive for *Escherichia coli*. The isolate demonstrates the following susceptibility profile:

Based on these findings, which of the following is the most appropriate next step in the management of this patient's infection?

Match the following calcium and parathyroid hormone (PTH) laboratory profiles with their most likely underlying etiologies.

An infectious diseases consultation is requested for a 48-year-old female who was admitted to the hospital three days ago with subacute onset of fever, fatigue, and dyspnea. Initial evaluation revealed a new holosystolic murmur radiating to the axilla. A transesophageal echocardiogram confirmed a $1.4\text{ cm}$ oscillating vegetation on the posterior mitral leaflet. Upon admission, three sets of blood cultures were drawn, and she was started on empiric intravenous vancomycin and ceftriaxone. Today, the patient is clinically stable, and her temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$). The microbiology laboratory reports that all three blood culture sets are growing *Streptococcus mutans*. The isolate has a penicillin minimum inhibitory concentration (MIC) of $0.06 \text{ mcg/mL}$ (highly susceptible) and is also susceptible to ceftriaxone. Based on the culture and susceptibility data, which of the following is the most appropriate modification to her pharmacotherapy?

Match each disease-modifying antirheumatic drug (DMARD) or immunosuppressive agent to its most characteristic adverse effect or required screening protocol.

Match each clinical vignette and laboratory profile with the most likely underlying etiology of the patient's acid-base disorder.

A 67-year-old man comes to the office for follow-up of recent unintentional weight loss, heat intolerance, and palpitations. He has a history of ischemic cardiomyopathy, heart failure with reduced ejection fraction, and paroxysmal atrial fibrillation. His medications include lisinopril, metoprolol succinate, furosemide, apixaban, and amiodarone, which was initiated two years ago for rhythm control. Vital signs show a blood pressure of $135/82$ mm Hg and a regular pulse of $105$/min. Physical examination reveals a fine tremor of the outstretched hands, warm and moist skin, and hyperactive deep tendon reflexes. The thyroid gland is not palpably enlarged, and no distinct nodules are appreciated. Laboratory studies show:

Thyroid-stimulating hormone (TSH): $<0.01$ $\mu$ U/mL
Free thyroxine (T4): $3.8$ ng/dL
Total triiodothyronine (T3): $210$ ng/dL

Which of the following is the most appropriate diagnostic test to differentiate the underlying mechanism of this patient's thyroid dysfunction?

A 35-year-old woman presents for follow-up of generalized weakness and worsening fatigue over the last two weeks. Her medical history is notable for Sjögren syndrome, for which she takes hydroxychloroquine. She appears comfortable and her vital signs are stable. Muscle strength testing demonstrates 4/5 strength in the bilateral quadriceps and hip flexors. Given her symptoms, laboratory testing is obtained:

Serum:
Sodium: 140 mEq/L
Potassium: 2.8 mEq/L
Chloride: 115 mEq/L
Bicarbonate: 15 mEq/L
Blood urea nitrogen: 14 mg/dL
Creatinine: 0.8 mg/dL
Glucose: 95 mg/dL

Urine:
Sodium: 60 mEq/L
Potassium: 25 mEq/L
Chloride: 45 mEq/L
pH: 6.0

To determine the etiology of this patient's metabolic acidosis, the physician decides to calculate the urine anion gap. What is the value of this patient's urine anion gap?

A 72-year-old man with a 50-pack-year smoking history and severe chronic obstructive pulmonary disease (COPD) comes to the clinic for evaluation of gradually increasing leg swelling over the past month. He reports his baseline shortness of breath with exertion, but he specifically denies waking up at night gasping for air and states he sleeps comfortably completely flat in his bed. Vital signs show a blood pressure of 128/82 mm Hg, pulse of 88/min, and oxygen saturation of 89% on room air. Physical examination reveals a barrel-shaped chest, distended jugular veins, a palpable parasternal heave, and bilateral 3+ pitting edema of the lower extremities. Auscultation of the lungs reveals distant breath sounds and prolonged expiration, but no crackles. Cardiac auscultation reveals distant heart sounds with no S3 gallop. Which of the following is the most likely primary underlying mechanism for this patient's peripheral edema?

A patient is being evaluated for recurrent fasting hypoglycemia. Match the following diagnostic laboratory profiles (obtained during a symptomatic hypoglycemic episode with plasma glucose $<$ $55$ mg/dL) with their most likely underlying etiology.

A 41-year-old woman presents to the clinic to evaluate a newly discovered lump in her neck. She noticed it two weeks ago while adjusting a necklace. She reports no pain, dysphagia, or hoarseness but admits to a recent onset of mild anxiety and intermittent palpitations, which she attributes to stress at work. She has no other medical conditions and takes no medications. Vital signs show a heart rate of $98$/min and blood pressure of $122/78$ mm Hg. Physical examination reveals a palpable, mobile, $2.5$-cm nodule in the right thyroid lobe with no cervical lymphadenopathy. A dedicated neck ultrasound confirms a $2.5$-cm solid, circumscribed nodule in the right thyroid lobe without suspicious sonographic features (e.g., no microcalcifications or irregular margins). Laboratory testing reveals a serum thyroid-stimulating hormone (TSH) level of $0.1$ $\mu$ U/mL (normal: 0.4–4.2 $\mu$ U/mL) and a free thyroxine (T4) level of $1.5$ ng/dL (normal: 0.8–2.7 ng/dL). Which of the following is the most appropriate next step in management?

A 56-year-old man is brought to the emergency department after vomiting a large volume of bright red blood. He has a history of decompensated alcohol-related cirrhosis. On presentation, he is lethargic but arousable. His temperature is 37.1°C (98.8°F), blood pressure is 88/52 mm Hg, pulse is 124/min, and respirations are 20/min. Physical examination reveals scleral icterus, palmar erythema, and a distended abdomen with a positive fluid wave. Arrange the following management steps in the most appropriate sequential order for this patient's acute presentation, from the initial immediate action to the ultimate rescue therapy.

A 62-year-old male with a history of alcohol-associated cirrhosis and chronic obstructive pulmonary disease (COPD) is brought to the emergency department by his wife due to severe weakness, confusion, and worsening shortness of breath over the past 24 hours. She reports that he passed a large volume of black, tarry stool earlier this morning.

On arrival, his temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), pulse is $122/\text{min}$, blood pressure is $88/54\text{ mm Hg}$, and respirations are $24/\text{min}$. Oxygen saturation is $94\%$ on room air. Physical examination reveals a lethargic but arousable patient with pale conjunctivae. Chest examination shows decreased breath sounds bilaterally but no crackles or wheezes. The abdomen is distended with shifting dullness. A coarse, flapping tremor is noted upon wrist extension.

Laboratory and diagnostic studies show the following:

A urine culture collected two days ago at an urgent care clinic for mild dysuria has returned positive for >100,000 CFU/mL of *Escherichia coli*. The isolate is sensitive to ceftriaxone, nitrofurantoin, and trimethoprim-sulfamethoxazole.

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

A 52-year-old man is hospitalized to undergo induction chemotherapy for newly diagnosed Burkitt lymphoma. Twenty-four hours after the initiation of the cytotoxic regimen, he reports new-onset muscle cramps, palpitations, and nausea. His temperature is 37.2°C (99.0°F), pulse is 108/min, and blood pressure is 110/70 mm Hg. Physical examination reveals normal heart sounds and clear lungs.

An electrocardiogram (ECG) reveals peaked T waves and a shortened QT interval. The patient is currently receiving aggressive intravenous normal saline and allopurinol. Which of the following is the most appropriate next step in management?

A 45-year-old woman comes to the clinic reporting progressive muscle weakness and recurrent cramping in her legs for the past three weeks. She also notes a several-month history of a sensation of "sand in her eyes" and a dry mouth requiring frequent sips of water. She takes no medications. Vital signs are within normal limits. Physical examination shows 4/5 motor strength in the lower extremities bilaterally with normal deep tendon reflexes.

Laboratory results are as follows:

Which of the following is the primary mechanism responsible for this patient's acid-base disturbance?

Match each classic auscultatory finding described below with its corresponding valvular heart disease.

Match each clinical exposure scenario with the most appropriate first-line oral antimicrobial regimen.

An emergency department physician evaluates a patient presenting with severe, unrelenting mid-back pain that has progressively worsened over the past week. The patient, who has a history of type 2 diabetes mellitus and injection drug use, now reports new-onset bilateral leg weakness and an inability to urinate for the past $6 \text{ hours}$. Vital signs show a temperature of $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$), heart rate of $110/\text{min}$, and blood pressure of $130/80\text{ mmHg}$. Physical examination demonstrates tenderness to percussion over the thoracic spine, $3/5$ motor strength in both lower extremities, and absent deep tendon reflexes at the knees and ankles. A bedside bladder ultrasound reveals a post-void residual volume of $600\text{ mL}$.

Arrange the following management steps in the most appropriate chronological sequence for this patient.

Match the following peripheral blood smear descriptions and associated clinical findings with their most likely underlying diagnosis or pathophysiologic state.