Internal Medicine

A 45-year-old male is evaluated in the surgical intensive care unit on postoperative day 3 following an extensive small bowel resection for mesenteric ischemia. Over the last 12 hours, the nursing staff reports that his urine output has decreased to $15 \text{ mL/hr}$. He has been receiving maintenance intravenous fluids but has had large volumes of nasogastric tube output. His temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $90/55 \text{ mmHg}$, and pulse is $118/\text{min}$. Physical examination reveals flat jugular veins, delayed capillary refill, and dry mucous membranes.

Laboratory studies are obtained:

Based on the provided laboratory values, what is this patient's fractional excretion of sodium (FENa)? (Provide your answer as a numerical percentage, e.g., if the calculated value is 1.2%, enter 1.2)

A 71-year-old female presents to the orthopedic clinic for a final preoperative evaluation. She is scheduled to undergo an elective right total knee arthroplasty in one week for severe osteoarthritis. Her medical history includes hypertension and diet-controlled type 2 diabetes mellitus. The patient feels well and reports no dysuria, urinary frequency, urgency, or suprapubic discomfort. Vital signs are within normal limits. Physical examination reveals crepitus and decreased range of motion in the right knee but is otherwise unremarkable. Routine preoperative laboratory testing is notable for a urinalysis demonstrating positive leukocyte esterase and 15 leukocytes/hpf. A reflex urine culture grows $>10^{5}$ CFU/mL of *Escherichia coli* that is susceptible to cephalexin, nitrofurantoin, ciprofloxacin, and trimethoprim-sulfamethoxazole. Which of the following is the most appropriate management regarding her urinary findings?

During an evening shift, a critical care team evaluates a patient who was transferred from an outside hospital following a suicide attempt. The patient was initially found stuporous by a roommate next to an empty bottle of an unknown over-the-counter medication. Prior to transfer, the patient experienced several episodes of large-volume, nonbilious emesis. Current vital signs include a temperature of $38.6^\circ\text{C}$ ($101.5^\circ\text{F}$), blood pressure of $110/68$ mmHg, heart rate of $122/\text{min}$, and respiratory rate of $34/\text{min}$.

Laboratory results are obtained:

Arterial blood gas (room air)
pH: $7.32$
pCO $_2$: $16$ mmHg
pO $_2$: $98$ mmHg

Serum chemistry
Na $^+$: $142$ mEq/L
K $^+$: $3.4$ mEq/L
Cl $^-$: $92$ mEq/L
HCO $_3^-$: $12$ mEq/L
BUN: $22$ mg/dL
Creatinine: $1.3$ mg/dL

Based on the laboratory data provided, which of the following combinations best describes this patient's primary acid-base disturbances?

A 56-year-old man with a history of alcohol-related cirrhosis is brought to the emergency department after vomiting a large amount of bright red blood. On arrival, he is somnolent, minimally responsive to pain, and actively retching blood. His Glasgow Coma Scale (GCS) score is 8. Vital signs are temperature $36.8^\circ C$ ($98.2^\circ F$), blood pressure $78/40$ mmHg, pulse $132$/min, and respiratory rate $22$/min. Physical examination shows scleral icterus, spider angiomas, and a distended abdomen with a positive fluid wave. Two large-bore peripheral intravenous lines are immediately established.

Assuming this patient's hemorrhage proves to be highly severe and refractory to standard definitive interventions, arrange the following management steps in the most appropriate sequential order (from first to last).

A $29$-year-old man is intubated and placed on mechanical ventilation in the intensive care unit for refractory status asthmaticus. His current ventilator settings on volume assist-control mode are: tidal volume $8$ mL/kg of ideal body weight, respiratory rate $18$/min, positive end-expiratory pressure (PEEP) $5$ cm H $_2$ O, and fraction of inspired oxygen (FiO $_2$) $1.0$. Ten minutes after intubation, the ventilator's high-pressure alarm sounds. His blood pressure is $76/42$ mm Hg and heart rate is $142$/min. The peak inspiratory pressure is $72$ cm H $_2$ O, and the plateau pressure (measured via a $0.5$-second end-inspiratory hold) is $24$ cm H $_2$ O. The ventilator's flow-time waveform indicates that expiratory flow does not return to zero before the initiation of the next breath. Which of the following are the most appropriate immediate interventions? (Select all that apply)

A 61-year-old critically ill female is evaluated in the intensive care unit on postoperative day 4 following an emergency exploratory laparotomy for ischemic colitis. Her postoperative course has been complicated by septic shock requiring broad-spectrum antibiotics and vasopressor support. She is currently intubated and sedated. Enteral nutrition was initiated yesterday. The patient has no history of thyroid disease. Her temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $105/65\text{ mmHg}$ on low-dose norepinephrine, and pulse is $88/\text{min}$. Physical examination shows a healing midline abdominal incision and no goiter.

Laboratory studies show:

Which of the following is the most appropriate next step in management of this patient's thyroid findings?

A 52-year-old woman with a history of breast cancer is evaluated in the emergency department for a fever that began earlier today. She received her last cycle of chemotherapy consisting of doxorubicin and cyclophosphamide 8 days ago. Her temperature is $38.6^\circ\text{C}$ ($101.5^\circ\text{F}$), blood pressure is $112/72 \text{ mmHg}$, and heart rate is $98 \text{ /min}$. Physical examination reveals a totally implanted central venous port in the right upper chest with no surrounding erythema, and no other clear source of infection. A complete blood count reveals a hemoglobin of $10.2 \text{ g/dL}$, platelet count of $115,000/\text{mm}^3$, and a white blood cell count of $800/\text{mm}^3$ with $30\%$ neutrophils. Arrange the following management steps in the most appropriate chronological sequence for this patient.

A 54-year-old male is evaluated on the medical ward on hospital day 6. He was initially admitted for severe acute pancreatitis complicated by a prolonged ileus, for which he is receiving total parenteral nutrition through a right internal jugular central venous catheter. Two days ago, the patient had a single temperature spike to 38.2°C (100.8°F). At that time, a complete blood count and two sets of blood cultures (one drawn from the central venous catheter and one from a peripheral vein) were obtained. Since then, the patient has remained afebrile and his abdominal pain has significantly improved. He currently reports feeling well. Vital signs today show a temperature of 37.0°C (98.6°F), blood pressure of 122/78 mm Hg, and heart rate of 78/min. Physical examination reveals a clean, non-erythematous central line exit site without tenderness or exudate. The white blood cell count has decreased from 14,500/mm³ on admission to 8,200/mm³ today. The microbiology laboratory calls to report that the aerobic bottle from the peripheral blood draw has signaled positive for coagulase-negative staphylococci at 42 hours of incubation. The other three culture bottles (anaerobic peripheral, aerobic central, anaerobic central) have shown no growth. Which of the following is the most appropriate next step in management?

For each of the following individuals presenting after a potential infectious exposure, select the most appropriate guideline-concordant prophylactic regimen.

A 68-year-old man with a history of severe chronic obstructive pulmonary disease (COPD) and heart failure with preserved ejection fraction is brought to the emergency department by his family due to a 3-day history of progressively worsening dyspnea, increased cough, and production of purulent sputum. Today, the family noted he has been increasingly lethargic and difficult to arouse. His current medications include tiotropium, an albuterol inhaler, lisinopril, and amlodipine.

On arrival, his temperature is $38.2^\circ \text{C}$ ($100.8^\circ \text{F}$), blood pressure is $110/70 \text{ mmHg}$, pulse is $118/\text{min}$, and respiratory rate is $28/\text{min}$. Oxygen saturation is $86\%$ on room air. Physical examination reveals a somnolent patient who responds only to painful stimuli. He is using accessory muscles of respiration. Jugular venous pressure is estimated at $7 \text{ cm H}_2\text{O}$. Lung auscultation reveals diffuse expiratory wheezing with prolonged expiration and scattered rhonchi; there are no crackles. Heart sounds are distant but regular, with no murmurs, rubs, or gallops. The extremities are warm with 1+ bilateral pitting edema to the ankles.

Laboratory evaluation shows:
Sodium: $138 \text{ mEq/L}$
Potassium: $4.8 \text{ mEq/L}$
Chloride: $102 \text{ mEq/L}$
Bicarbonate: $14 \text{ mEq/L}$
Blood urea nitrogen: $42 \text{ mg/dL}$
Creatinine: $2.1 \text{ mg/dL}$ (Baseline $1.2 \text{ mg/dL}$)
Lactic acid: $5.2 \text{ mmol/L}$

Arterial blood gas analysis on room air reveals:
pH: $7.15$
PaCO2: $42 \text{ mmHg}$
PaO2: $52 \text{ mmHg}$

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

A $61$-year-old man with a known history of decompensated cirrhosis secondary to alcohol use disorder presents to the emergency department reporting a two-day history of fever, fatigue, and worsening abdominal swelling. His temperature is $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$), blood pressure is $112/68\text{ mm Hg}$, and pulse is $98/\text{min}$. Physical examination demonstrates a markedly distended abdomen with positive shifting dullness and mild, diffuse tenderness to palpation. There is no rebound tenderness or abdominal rigidity. A diagnostic paracentesis is promptly performed. The ascitic fluid analysis reveals a total leukocyte count of $1,200/\text{mm}^3$ with $70\%$ segmented neutrophils. Based on these findings, which of the following is the most appropriate targeted pharmacotherapy for this patient's current condition?

A 64-year-old male is evaluated in the hospital on day $4$ of admission. He initially presented with right upper quadrant abdominal pain, high-grade fevers, and profound fatigue. His past medical history is significant for type 2 diabetes mellitus. Upon admission, a computed tomography (CT) scan of the abdomen with intravenous contrast demonstrated a single, $5.5\text{ cm}$, thick-walled, hypodense fluid collection in the right hepatic lobe. He was started on empiric intravenous piperacillin-tazobactam. A CT-guided percutaneous drain was subsequently placed, which yielded $40\text{ mL}$ of purulent material. Currently, his temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), heart rate is $82/\text{min}$, and blood pressure is $128/84\text{ mmHg}$. His leukocyte count has decreased from $18,200/\text{mm}^3$ on admission to $8,400/\text{mm}^3$. Blood cultures drawn on admission are negative. The abscess fluid culture has finalized, demonstrating a pure growth of *Streptococcus anginosus*. Susceptibility testing reveals the organism is susceptible to penicillin, ceftriaxone, and clindamycin, but resistant to erythromycin. Which of the following is the most appropriate next step in pharmacotherapy?

An extensively evaluated $48$-year-old individual is referred to the endocrine clinic for persistent blood pressure elevations. The patient's blood pressure is $168/102$ mmHg despite documented adherence to a three-drug antihypertensive regimen, which includes amlodipine, valsartan, and hydrochlorothiazide. Recent laboratory evaluation reveals a serum potassium level of $2.8$ mEq/L. The physician suspects an underlying adrenal etiology for the patient's presentation. Assuming positive findings at each stage that warrant further investigation, arrange the following diagnostic procedures in the correct chronological sequence to definitively diagnose and prepare this patient for targeted surgical intervention.

A 58-year-old man presents to the outpatient clinic with a 3-month history of reproducible substernal chest pressure. The pain occurs consistently after walking three blocks and resolves completely within 5 minutes of resting. He has a medical history of hypertension, type 2 diabetes mellitus, and hyperlipidemia. His current medications include lisinopril, metformin, and atorvastatin. Vital signs are within normal limits, and physical examination is unremarkable. Arrange the following interventions in the most appropriate chronological sequence for the evaluation and management of this patient's condition.

A 34-year-old man is brought to the emergency department after being found unresponsive in his garage. Emergency medical personnel found a half-empty container of commercial antifreeze nearby. His blood pressure is 145/90 mm Hg, pulse is 112/min, and respirations are 24/min. Physical examination reveals deep, rapid breathing.

Laboratory studies show the following:
Serum sodium: 142 mEq/L
Serum potassium: 4.5 mEq/L
Serum chloride: 104 mEq/L
Serum bicarbonate: 12 mEq/L
Blood urea nitrogen: 28 mg/dL
Serum creatinine: 1.4 mg/dL
Serum glucose: 126 mg/dL
Measured serum osmolality: 345 mOsm/kg $H_2O$

Arterial blood gas on room air shows a pH of 7.22 and $pCO_2$ of 26 mm Hg.

Based on the provided laboratory values, what is this patient's serum osmolar gap?

A fundamental step in the evaluation of suspected autoimmune and inflammatory conditions of the gastrointestinal tract and liver is the identification of specific autoantibodies. Match each of the following clinical diagnoses with its most characteristic serologic marker.

Match the following clinical vignettes describing zoonotic and environmental infections with their most appropriate targeted antimicrobial therapy.

Match each brief clinical presentation of a hepatobiliary disorder to its most specific diagnostic laboratory or imaging finding.

A 64-year-old woman comes to the emergency department complaining of severe difficulty breathing that has progressively worsened over the last 72 hours. She also reports a persistent nighttime cough and states she must prop herself up with three pillows to sleep without feeling like she is suffocating. Her medical history includes hypertension, type 2 diabetes mellitus, and a 35-pack-year smoking history. Her temperature is 37.1°C (98.8°F), blood pressure is 162/94 mmHg, pulse is 108/min, and respirations are 24/min. Oxygen saturation is 92% on room air. Physical examination reveals distended neck veins when sitting at a 45-degree angle. Auscultation of the lungs demonstrates bibasilar crackles without wheezing. Cardiac auscultation reveals a regular rhythm, tachycardia, and a prominent S3 gallop. Examination of the lower extremities shows bilateral 2+ pitting edema extending to the mid-calves. Which of the following is the most appropriate initial pharmacological intervention for this patient?

A 52-year-old male is transported to the emergency department following an episode where he coughed up approximately 600 mL of bright red blood at home. He has a remote history of treated pulmonary tuberculosis. Upon arrival, the patient is actively coughing up additional large volumes of blood and appears in significant respiratory distress. Vital signs show a blood pressure of 105/65 mmHg, heart rate of 118/min, respiratory rate of 26/min, and oxygen saturation of 88% on room air. Chest auscultation demonstrates coarse crackles and absent breath sounds strictly over the right hemithorax; the left hemithorax is completely clear.

Arrange the following interventions for this patient in the most appropriate sequential order, proceeding from immediate bedside management to definitive care.