A 74-year-old man is assessed in the surgical intensive care unit for a new-onset fever. H… — USMLE Step 2 CK

A $74$ -year-old man is assessed in the surgical intensive care unit for a new-onset fever. He is currently on postoperative day $10$ following an emergency open repair of a ruptured abdominal aortic aneurysm. His postoperative course has been complicated by hemorrhagic shock requiring massive transfusion and acute kidney injury that is slowly resolving. He was successfully extubated two days ago. Today, his temperature is $39.1^\circ\text{C}$ ( $102.4^\circ\text{F}$ ), blood pressure is $105/65\text{ mmHg}$ , and heart rate is $112/\text{min}$ . He is delirious and cannot accurately localize pain. Physical examination reveals mild scleral icterus. The abdomen is distended with absent bowel sounds; there is voluntary guarding in the right upper quadrant when deep palpation is performed. The midline surgical incision is clean and intact. Laboratory studies show:

Leukocyte count: $21,500/\text{mm}^3$
Total bilirubin: $2.8\text{ mg/dL}$
Direct bilirubin: $2.1\text{ mg/dL}$
Alkaline phosphatase: $320\text{ U/L}$
Aspartate aminotransferase (AST): $55\text{ U/L}$
Alanine aminotransferase (ALT): $62\text{ U/L}$
Blood urea nitrogen: $45\text{ mg/dL}$
Serum creatinine: $2.4\text{ mg/dL}$

Which of the following is the most appropriate initial diagnostic test?

Right upper quadrant ultrasonographyCevap
B
Computed tomography of the abdomen and pelvis with intravenous contrast
C
Hepatobiliary iminodiacetic acid scintigraphy
D
Endoscopic retrograde cholangiopancreatography
E
Sputum Gram stain and chest radiography

Cevap

Right upper quadrant ultrasonography

The correct answer is right upper quadrant ultrasonography. This critically ill patient's late-onset postoperative fever, leukocytosis, mild right upper quadrant tenderness, and cholestatic liver enzyme pattern (elevated alkaline phosphatase and direct bilirubin) are highly suspicious for acute acalculous cholecystitis. This severe condition typically occurs in hospitalized patients suffering from critical illnesses, such as hemorrhagic shock, severe trauma, sepsis, or prolonged mechanical ventilation. These systemic insults lead to profound gallbladder stasis and ischemia, resulting in inflammation and necrosis without the presence of gallstones. The most appropriate initial diagnostic test is a right upper quadrant abdominal ultrasound. It is fast, non-invasive, can be performed at the bedside in the intensive care unit, avoids nephrotoxic contrast, and effectively identifies characteristic signs such as gallbladder wall thickening, pericholecystic fluid, and biliary sludge.

Adım Adım Çözüm

Analyze the patient's clinical presentation and postoperative timeline.

The patient is a critically ill man on postoperative day

10

with new-onset fever, severe leukocytosis, right upper quadrant tenderness, and cholestatic jaundice.

Establishing the timeline and identifying focal findings is necessary to narrow the differential diagnosis of a late-onset postoperative fever.

Synthesize the patient's risk factors with the physical and laboratory findings.

The combination of critical illness (shock, massive transfusion, acute kidney injury) and cholestatic laboratory derangements strongly suggests acute acalculous cholecystitis.

Gallbladder ischemia and profound stasis in critically ill patients lead to acute acalculous cholecystitis, presenting with late fever and right upper quadrant signs.

Determine the safest and most appropriate diagnostic modality.

Bedside right upper quadrant ultrasonography is selected as the initial test.

Ultrasonography is highly sensitive for gallbladder wall thickening and pericholecystic fluid, can be performed immediately at the bedside, and safely avoids nephrotoxic contrast in a patient with acute kidney injury.

Anahtar Kavram

Diagnosis of acute acalculous cholecystitis in critically ill patients

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Cevap

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