A 60-year-old man presents to the emergency department with a 2-day history of fever, abdominal pain, and confusion. He has a history of chronic hepatitis C and liver cirrhosis. His medications include furosemide and spironolactone. His temperature is 38.5°C (101.3°F), blood pressure is 100/60 mm Hg, pulse is 112/min, and respiratory rate is 22/min. On physical examination, he appears jaundiced and has scleral icterus. Abdominal examination reveals a distended abdomen with shifting dullness and generalized tenderness to palpation. Laboratory results are as follows:
Which of the following is the most appropriate next step in the management of this patient?
B) Cell count and differential of ascitic fluid
This patient with a history of cirrhosis presents with fever, abdominal pain, and confusion, which are signs suggestive of spontaneous bacterial peritonitis (SBP). The most sensitive test for SBP is a diagnostic paracentesis with fluid analysis, including cell count and differential. An ascitic neutrophil count of ≥250/mm³ is diagnostic of SBP and warrants empiric intravenous antibiotics. Although ascitic culture and Gram stain are also collected, they have lower sensitivity compared to cell count and differential. Hence, the immediate next step should be cell count and differential of ascitic fluid to confirm the diagnosis of SBP and initiate appropriate treatment.
Answer choice A: Blood cultures, is incorrect. Blood cultures can help identify bacteremia but have lower sensitivity for diagnosing SBP compared to ascitic fluid analysis. The primary concern is to confirm SBP directly through ascitic fluid analysis.
Answer choice C: CT scan of the abdomen. A CT scan can identify anatomical abnormalities and complications such as abscess or perforation. However, it is not the first-line diagnostic tool for suspected SBP, which is better diagnosed with ascitic fluid analysis.
Answer choice D: Culture and Gram stain of ascitic fluid. While culture and Gram stain results of ascitic fluid are part of the diagnostic workup for SBP, they are not as immediately diagnostic as the cell count and differential. Culture and Gram stain results take time, whereas cell count and differential can provide quicker results to guide immediate management.
Answer choice E: Ultrasonography of the hepatic veins. Ultrasonography of the hepatic veins is used to evaluate for conditions like Budd-Chiari syndrome, which involves hepatic venous outflow obstruction. It is not the first step in the acute setting of suspected SBP, where diagnostic paracentesis is more direct and informative.
Key Learning Point
In a cirrhotic patient with fever, abdominal pain, and confusion, suggestive of spontaneous bacterial peritonitis (SBP), the most appropriate next step is a diagnostic paracentesis with cell count and differential of ascitic fluid. An ascitic neutrophil count of ≥250/mm3 confirms SBP and warrants immediate antibiotic treatment.
