A 57-year-old man with a history of alcohol-associated cirrhosis is brought to the emergen… — USMLE Step 2 CK

A 57-year-old man with a history of alcohol-associated cirrhosis is brought to the emergency department by his family due to increasing confusion and lethargy over the past 24 hours. He has also complained of diffuse abdominal discomfort. His current medications include spironolactone, furosemide, and lactulose. His temperature is $38.1^\circ\text{C}$ ( $100.6^\circ\text{F}$ ), blood pressure is $105/65\text{ mm Hg}$ , and pulse is $96/\text{min}$ . Physical examination reveals scleral icterus, spider angiomas, and a distended abdomen with shifting dullness. He is oriented only to person. Asterixis is present. Diagnostic paracentesis is performed, yielding cloudy fluid. Ascitic fluid analysis shows:

Laboratory Test	Result
Total protein	$1.1\text{ g/dL}$
Leukocyte count	$600/\mu\text{L}$
Neutrophils	$80\%$

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

Intravenous ceftriaxoneAnswer
B
Intravenous meropenem
C
Immediate exploratory laparotomy
D
Increase dosage of oral lactulose
E
Oral ciprofloxacin

Answer

Intravenous ceftriaxone

The correct answer is intravenous ceftriaxone. This patient's ascitic fluid analysis shows a leukocyte count of

600/\mu\text{L}

with

80\%

neutrophils. The absolute neutrophil count (ANC) is calculated by multiplying these values (

600 \times 0.80

), resulting in an ANC of

480/\mu\text{L}

. An ascitic fluid ANC

\geq 250/\mu\text{L}

is diagnostic for spontaneous bacterial peritonitis (SBP). SBP is a severe infection in patients with cirrhosis and ascites, and it frequently precipitates hepatic encephalopathy (as seen with this patient's lethargy, confusion, and asterixis). The most common pathogens are enteric Gram-negative bacteria (e.g., Escherichia coli, Klebsiella pneumoniae) and Streptococcus species. Empiric therapy must be initiated promptly, and intravenous third-generation cephalosporins (such as ceftriaxone or cefotaxime) are the first-line treatment of choice due to their excellent coverage of these organisms and good ascitic fluid penetration.

Step-by-Step Solution

Calculate the absolute neutrophil count (ANC) of the ascitic fluid.

The ANC is calculated as

600/\mu\text{L} \times 0.80 = 480/\mu\text{L}

An ANC

\geq 250/\mu\text{L}

in ascitic fluid is the diagnostic criterion for spontaneous bacterial peritonitis (SBP).

Identify the patient's primary clinical issue based on the calculated ANC.

The patient has spontaneous bacterial peritonitis (SBP) which has precipitated acute hepatic encephalopathy.

Underlying infections are the most common triggers for acute hepatic encephalopathy in cirrhotic patients.

Select the most appropriate empiric antimicrobial therapy.

Intravenous ceftriaxone (or cefotaxime).

Intravenous third-generation cephalosporins provide optimal coverage for the most common causative organisms of SBP (enteric Gram-negative rods and Streptococcus species) without unnecessarily broad spectrum.

Key Concept

Diagnosis and management of Spontaneous Bacterial Peritonitis (SBP)

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic