A 58-year-old man with a history of cirrhosis secondary to untreated hepatitis C is admitt… — USMLE Step 2 CK

A $58$ -year-old man with a history of cirrhosis secondary to untreated hepatitis C is admitted to the hospital due to progressive lethargy and abdominal distension over the past $48$ hours. His temperature is $38.2^\circ\text{C}$ ( $100.8^\circ\text{F}$ ), pulse is $102/\text{min}$ , blood pressure is $105/65\text{ mmHg}$ , and respirations are $18/\text{min}$ . Physical examination reveals scleral icterus, a distended abdomen with shifting dullness, and diffuse mild tenderness without rebound or guarding. Asterixis is present.

Laboratory studies show:

Laboratory Test	Result
Leukocyte count	$11,500/\text{mm}^3$
Serum creatinine	$1.8 \text{ mg/dL}$ (baseline: $1.1 \text{ mg/dL}$ )
Blood urea nitrogen	$42 \text{ mg/dL}$
Total bilirubin	$3.5 \text{ mg/dL}$
Arterial blood gas	pH $7.32$ , pCO $_2$ $30 \text{ mmHg}$ , HCO $_3^-$ $16 \text{ mEq/L}$

A diagnostic paracentesis is performed:

Ascitic Fluid Analysis	Result
Appearance	Turbid
Total nucleated cells	$800/\text{mm}^3$
Neutrophils	$80\%$
Total protein	$1.1 \text{ g/dL}$

The patient is immediately started on intravenous cefotaxime. Which of the following is the most appropriate additional step in this patient's management?

Intravenous administration of albuminAnswer
B
Addition of intravenous vancomycin and piperacillin-tazobactam
C
Emergent exploratory laparotomy
D
Initiation of intravenous furosemide and spironolactone
E
Intravenous administration of sodium bicarbonate

Answer

Intravenous administration of albumin

The correct answer identifies the crucial adjunctive role of intravenous albumin in spontaneous bacterial peritonitis (SBP). This patient's ascitic fluid absolute neutrophil count (ANC) is

640/\text{mm}^3

(calculated as

800 \times 0.80

), which is

> 250/\text{mm}^3

, confirming the diagnosis of SBP. He concurrently has an acute kidney injury with a serum creatinine of

1.8 \text{ mg/dL}

(baseline

1.1 \text{ mg/dL}

) and BUN of

42 \text{ mg/dL}

. SBP causes profound splanchnic vasodilation, which can severely reduce the effective arterial blood volume and precipitate hepatorenal syndrome (HRS). The administration of intravenous albumin (

1.5 \text{ g/kg}

on day 1, and

1.0 \text{ g/kg}

on day 3) provides critical plasma volume expansion. Guidelines mandate albumin for patients with SBP who have a serum creatinine

> 1.0 \text{ mg/dL}

, a BUN

> 30 \text{ mg/dL}

, or a bilirubin

> 4.0 \text{ mg/dL}

, as it significantly decreases the incidence of renal impairment and improves survival.

Step-by-Step Solution

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

ANC = Total nucleated cells

\times

percentage of neutrophils =

800 \times 0.80 = 640/\text{mm}^3

An ANC

\geq 250/\text{mm}^3

is diagnostic for spontaneous bacterial peritonitis (SBP).

Identify high-risk features for hepatorenal syndrome (HRS) in this patient with SBP.

The patient has an elevated serum creatinine (

1.8 \text{ mg/dL}

) and blood urea nitrogen (

42 \text{ mg/dL}

Patients with SBP are at high risk for HRS if their serum creatinine is

> 1.0 \text{ mg/dL}

, BUN is

> 30 \text{ mg/dL}

, or total bilirubin is

> 4.0 \text{ mg/dL}

Determine the appropriate adjunctive therapy to antibiotic treatment for high-risk SBP.

Intravenous albumin must be administered alongside a third-generation cephalosporin.

Albumin prevents the extreme vasodilation and severe effective arterial blood volume depletion that triggers HRS, significantly reducing mortality in this subset of patients.

Key Concept

In patients with spontaneous bacterial peritonitis (SBP) who have concurrent acute kidney injury or high-risk features (BUN

> 30 \text{ mg/dL}

, creatinine

> 1.0 \text{ mg/dL}

), intravenous albumin must be given alongside targeted antibiotics to prevent hepatorenal syndrome and reduce mortality.

Estimated Time:1m 30s

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