Internal Medicine

A 38-year-old man comes to the clinic complaining of a 3-week history of right upper quadrant abdominal pain, low-grade fevers, and profound fatigue. He emigrated from an endemic region of Central America 4 months ago. He does not use tobacco, alcohol, or illicit drugs. His temperature is 38.3°C (100.9°F), blood pressure is 122/78 mm Hg, and pulse is 88/min. Physical examination shows a liver edge that is palpable 3 cm below the right costal margin with marked point tenderness over the lower right rib cage. A complete blood count reveals a leukocyte count of 13,500/mm³ with 75% neutrophils. An abdominal ultrasound reveals a solitary, hypoechoic, 5-cm fluid collection in the right hepatic lobe. Enzyme immunoassay for *Entamoeba histolytica* antibodies is positive. Which of the following is the most appropriate next step in management?

Paramedics transport a 45-year-old male to the hospital after his wife discovered him confused and stumbling inside their garage. The patient reports severe bilateral flank pain and appears visibly intoxicated, though his wife states he has not consumed alcohol. Vital signs include a temperature of 37.1°C (98.8°F), blood pressure of 145/90 mm Hg, heart rate of 98/min, and respiratory rate of 22/min.

Based on the provided laboratory data, determine this patient's serum osmolar gap in mOsm/kg H₂O.

A 65-year-old man is evaluated on postoperative day 3 following an uncomplicated laparoscopic hemicolectomy for diverticular disease. He reports the sudden onset of severe right knee pain and swelling that began overnight. He is unable to bear weight on the right leg. His medical history is significant for hypertension, type 2 diabetes mellitus, and chronic kidney disease stage 4. Current medications include amlodipine, lisinopril, furosemide, and subcutaneous enoxaparin. Temperature is 38.0°C (100.4°F), blood pressure is 148/92 mmHg, pulse is 92/min, and respirations are 16/min. Physical examination reveals a warm, erythematous, and swollen right knee with a significant effusion. Passive range of motion is markedly decreased due to pain. Examination of the calves reveals no cords or localized tenderness. Laboratory studies show a serum creatinine of 2.6 mg/dL (baseline 2.5 mg/dL). Arthrocentesis of the right knee yields cloudy yellow fluid. Synovial fluid analysis reveals:

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

Match each clinical presentation with the specific autoantibody most highly associated with the patient's underlying rheumatologic condition.

A $68$-year-old woman is evaluated in the intensive care unit due to high-pressure ventilator alarms. She is on postoperative day $3$ following an exploratory laparotomy for a perforated diverticulum. Her past medical history includes severe chronic obstructive pulmonary disease, heart failure with preserved ejection fraction, and chronic kidney disease. She has been heavily sedated and on volume assist-control mechanical ventilation since surgery.

She is currently receiving targeted intravenous ceftriaxone, as peritoneal fluid cultures from the surgery are growing pan-sensitive *Escherichia coli*.

Current vital signs:
Temperature: $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$)
Blood pressure: $105/65\text{ mmHg}$
Heart rate: $118/\text{min}$
Oxygen saturation: $93\%$ on an $\text{FiO}_2$ of $0.40$

Current ventilator settings:
Tidal volume: $400\text{ mL}$ ($6\text{ mL/kg}$ predicted body weight)
Respiratory rate: $16/\text{min}$
PEEP: $8\text{ cm H}_2\text{O}$

The peak inspiratory pressure has abruptly increased to $58\text{ cm H}_2\text{O}$ (was $28\text{ cm H}_2\text{O}$ four hours ago).
The physician performs an end-inspiratory hold maneuver, which reveals a plateau pressure of $24\text{ cm H}_2\text{O}$ (unchanged from four hours ago).

Arterial blood gas analysis reveals:
pH: $7.21$
$\text{PaCO}_2$: $66\text{ mmHg}$
$\text{PaO}_2$: $68\text{ mmHg}$
$\text{HCO}_3^-$: $26\text{ mEq/L}$

Physical examination reveals scattered wheezes bilaterally and a prolonged expiratory phase. Cardiac examination shows tachycardia with a regular rhythm. The abdomen is tender but without surgical site erythema.

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

Emergency medical personnel transport a 21-year-old female university student to the emergency department after her roommates found her profoundly confused and breathing rapidly. The roommates report that she has been studying intensely for final exams over the past week and had complained of a persistent "ringing in her ears" earlier in the day. She has no known past medical history and takes no prescribed medications.

Vital signs reveal:
* Temperature: 38.2°C (100.8°F)
* Blood pressure: 112/68 mm Hg
* Heart rate: 115/min
* Respiratory rate: 28/min

Physical examination shows an agitated, diaphoretic patient with prominent hyperreflexia.

Initial laboratory test results are shown below:

An arterial blood gas sample obtained on room air reveals:

Based on the provided laboratory data, which of the following best describes the acid-base disturbance present in this patient?

Review the following clinical scenarios of patients with suspected congenital adrenal hyperplasia. Match each patient's clinical presentation and laboratory profile to the most likely specific deficient adrenal enzyme.

A 28-year-old woman comes to the clinic reporting right calf pain that started 2 days ago. She states the pain began the day after she participated in a new high-intensity jump-rope workout class. She has no significant past medical history, takes no medications, and has no personal or family history of venous thromboembolism. She does not use tobacco or illicit drugs. Her vital signs are within normal limits. Physical examination reveals mild localized tenderness in the right posterior calf muscle. There is no erythema, warmth, prominent superficial veins, or pitting edema. The right calf circumference is $1.5\text{ cm}$ larger than the left calf when measured $10\text{ cm}$ below the tibial tuberosity. Arrange the following steps in the most appropriate sequential order for the evidence-based diagnostic evaluation and management of this patient.

Match each patient's clinical presentation and diagnostic findings with the most definitive histopathologic pattern expected on their liver biopsy.

A 52-year-old man is brought to the emergency department via ambulance after vomiting a large amount of bright red blood at home. He has a history of alcohol use disorder and was diagnosed with decompensated cirrhosis two years ago. On arrival, his blood pressure is 85/55 mm Hg, and his pulse is 120/min. Physical examination reveals scleral icterus, multiple spider angiomas on the upper chest, and a distended abdomen with a positive fluid wave. Arrange the following steps in the most appropriate chronological order for managing this patient's acute presentation.

An otherwise healthy 30-year-old construction worker presents to an urgent care center reporting localized pain and swelling on his left thigh that began four days ago. He recalls a minor abrasion at the site but denies fevers, chills, or systemic symptoms. His vital signs are within normal limits. Physical examination demonstrates a 3.5-cm, exquisitely tender, erythematous, and fluctuant nodule on the anterolateral aspect of the left thigh. There is spontaneous drainage of a small amount of purulent fluid. No surrounding induration extending beyond the immediate area, crepitus, or regional lymphadenopathy is appreciated. Which of the following is the most appropriate management for this patient?

Appropriate antimicrobial stewardship is critical in gastroenterology to prevent resistance, adverse drug effects, and disease exacerbation. Match the following clinical presentations of gastrointestinal and hepatobiliary conditions with their correct antimicrobial management strategy.

A 71-year-old woman is evaluated in the intensive care unit for progressive abdominal distension and altered mental status. She was admitted four days ago for severe *Clostridioides difficile* infection and was appropriately started on oral vancomycin. Today, she is lethargic and confused. Her temperature is $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$), blood pressure is $84/52\text{ mm Hg}$, pulse is $124/\text{min}$, and respiratory rate is $22/\text{min}$. Physical examination reveals a markedly distended, tympanitic abdomen with diffuse tenderness. Bowel sounds are absent. She has had no bowel movements in the past $24$ hours. Laboratory studies show a leukocyte count of $32,000/\text{mm}^3$ and a serum creatinine level of $2.3\text{ mg/dL}$. An abdominal radiograph demonstrates colonic dilation measuring $9\text{ cm}$ in the transverse colon, with loss of haustral markings and no free intraperitoneal air. Which of the following is the most appropriate next step in the management of this patient's infection?

A concerned dormitory resident advisor escorts a 20-year-old female undergraduate to the university health center. The student complains of a constant "buzzing" sound in her ears, dizziness, and a feeling of being "short of breath" since waking up this morning. She admits to consuming an entire bottle of over-the-counter pain relievers last night following a difficult personal event. Her temperature is 37.6°C (99.7°F), blood pressure is 112/68 mmHg, pulse is 118/min, and respiratory rate is 26/min. She is diaphoretic and appears anxious. Laboratory evaluation reveals the following:

Which of the following is the most accurate interpretation of this patient's acid-base status?

A $62$-year-old man comes to the clinic reporting a $3$-month history of a persistent dry cough and progressively worsening shortness of breath. He can currently walk only one block before needing to stop. He has a $12$-year history of seropositive rheumatoid arthritis, which is treated with weekly oral methotrexate and daily folic acid. He is a lifelong nonsmoker. His temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $132/82\text{ mmHg}$, pulse is $86/\text{min}$, and respiratory rate is $20/\text{min}$. Pulse oximetry shows $93\%$ on room air. Physical examination reveals fine, "Velcro-like" end-inspiratory crackles at both lung bases. Jugular venous pressure is normal, and cardiac examination reveals a regular rate and rhythm with no murmurs or gallops. There is no peripheral edema. Musculoskeletal examination shows ulnar deviation of the fingers bilaterally but no acute joint swelling or tenderness.

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

Match each clinical presentation of an opportunistic infection in an immunocompromised patient with the most appropriate first-line targeted pharmacotherapy.

A 71-year-old resident of a long-term care facility is evaluated for a three-day history of frequent, watery bowel movements and mild abdominal cramping. The patient recently completed a 7-day course of oral ciprofloxacin for an uncomplicated urinary tract infection. Temperature is 37.7°C (99.9°F), blood pressure is 120/78 mmHg, and pulse is 90/min. Physical examination reveals mild, diffuse abdominal tenderness without rebound or guarding. Laboratory studies show a leukocyte count of 14,000/mm³. A stool nucleic acid amplification test is positive for Clostridioides difficile. Which of the following is the most appropriate pharmacotherapy for this patient?

During morning rounds, a patient who underwent right total knee arthroplasty $6$ days ago is evaluated for new-onset left leg pain and swelling. The patient, a female in her mid-sixties, has been receiving standard postoperative venous thromboembolism prophylaxis with subcutaneous unfractionated heparin since the day of surgery.

Vital signs are:
Temperature: $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$)
Heart rate: $92\text{/min}$
Blood pressure: $128/82\text{ mm Hg}$
Respiratory rate: $14\text{/min}$
Oxygen saturation: $97\%$ on room air

Physical examination reveals a swollen, erythematous, and tender left calf. The right surgical site is healing appropriately without signs of infection or excessive bleeding.

Laboratory studies are as follows:

Admission (Day 0):
Hemoglobin: $13.5\text{ g/dL}$
Platelet count: $280,000/\mu\text{L}$

Today (Day 6):
Hemoglobin: $12.8\text{ g/dL}$
Platelet count: $118,000/\mu\text{L}$
Leukocyte count: $7,200/\mu\text{L}$

Based on these findings, which of the following is the most appropriate next step in management?

A 42-year-old woman presents to the emergency department with a $12\text{-hour}$ history of severe, constant, epigastric pain that radiates to her back. The pain is associated with nausea and multiple episodes of nonbilious vomiting. She has no significant past medical history and does not consume alcohol. Her temperature is $37.3^\circ\text{C}$ ($99.1^\circ\text{F}$), pulse is $112\text{/min}$, and blood pressure is $132/84\text{ mm Hg}$. Physical examination reveals marked epigastric tenderness to deep palpation without rebound or guarding. Bowel sounds are decreased.

Laboratory studies show:
Leukocyte count: $11,500/\text{mm}^3$
Alanine aminotransferase (ALT): $185\text{ U/L}$
Aspartate aminotransferase (AST): $150\text{ U/L}$
Alkaline phosphatase: $110\text{ U/L}$
Total bilirubin: $1.0\text{ mg/dL}$
Lipase: $2,400\text{ U/L}$

A right upper quadrant ultrasound shows multiple gallstones in the gallbladder but a normal-caliber common bile duct without sonographic evidence of choledocholithiasis. Which of the following is the most appropriate next step in management?

A 28-year-old woman, gravida 1 para 0, at 18 weeks gestation, is evaluated in the intensive care unit. She was admitted three days ago for a severe exacerbation of pan-ulcerative colitis characterized by 15 bloody bowel movements daily. Upon admission, she was initiated on intravenous hydrocortisone, aggressive fluid resuscitation, and empiric intravenous ciprofloxacin and metronidazole. Blood cultures drawn on admission have since grown $Bacteroides fragilis$ that is susceptible to metronidazole. Today, the patient is lethargic. Her temperature is $39.5^\circ\text{C}$ ($103.1^\circ\text{F}$), pulse is $138\text{/min}$, blood pressure is $80/50\text{ mmHg}$, and respirations are $28\text{/min}$. Physical examination reveals a gravid uterus consistent with gestational age. The abdomen is markedly distended, tympanic, and exhibits diffuse rigidity with rebound tenderness. Laboratory studies show:

Leukocyte count: $26,000/\text{mm}^3$
Hemoglobin: $10.8\text{ g/dL}$

Arterial blood gas (room air):
pH: $7.18$
$\text{pCO}_2$: $42\text{ mmHg}$
$\text{HCO}_3^-$: $15\text{ mEq/L}$

An abdominal radiograph (performed with appropriate fetal shielding) demonstrates a continuous segment of transverse colon dilated to $9.5\text{ cm}$ with complete loss of haustral markings. No free intraperitoneal air is visualized.

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