What is the diagnosis for a 19-year-old male presenting with jaundice, hyperthermia, abdominal distension, and ascites?

Diagnosis: Spontaneous Bacterial Peritonitis (SBP) in the Setting of Cirrhotic Ascites

This 19-year-old man most likely has spontaneous bacterial peritonitis complicating cirrhotic ascites, and requires immediate diagnostic paracentesis with ascitic fluid analysis followed by empirical antibiotic therapy. 1

Immediate Diagnostic Approach

Perform diagnostic paracentesis immediately - this is the most rapid and efficient test to establish both the cause of ascites and detect infection. 1 The combination of fever (38.9°C), jaundice, abdominal distension with confirmed ascites (positive shifting dullness), and abdominal tenderness in a young patient creates high suspicion for infected ascites. 1

Critical Ascitic Fluid Studies Required:

• Cell count with differential - SBP is diagnosed when absolute neutrophil count >250/mm³ 1
• Albumin level - to calculate serum-ascites albumin gradient (SAAG) 2
• Total protein concentration - to assess infection risk 1
• Inoculate fluid into blood culture bottles at bedside - improves organism isolation 2
• Gram stain and culture - though diagnosis should not await results 1

Why SBP is the Leading Diagnosis

The clinical presentation strongly suggests SBP because:

• Fever with ascites - SBP prevalence is approximately 10% in hospitalized cirrhotic patients, and up to one-third may present with fever 1
• Abdominal tenderness - specific for SBP when present, though notably up to one-third of SBP patients are entirely asymptomatic 1
• Jaundice - bacterial infection commonly causes clinical deterioration with worsening jaundice in cirrhosis 1
• Young age - suggests underlying chronic liver disease from causes like Wilson disease, autoimmune hepatitis, or viral hepatitis 3

Underlying Etiology Considerations

The SAAG will distinguish the cause of ascites with 97% accuracy: 2

• SAAG ≥1.1 g/dL indicates portal hypertension - cirrhosis accounts for 75-85% of ascites cases and is the most likely underlying diagnosis 1
• SAAG <1.1 g/dL suggests alternative causes including peritoneal tuberculosis, peritoneal carcinomatosis, or pancreatitis 1

In a 19-year-old with jaundice and ascites, consider:

• Viral hepatitis (hepatitis B or C leading to cirrhosis)
• Wilson disease - can present with jaundice, ascites, and hepatosplenomegaly in young patients 3
• Autoimmune hepatitis - common cause of cirrhosis in young adults 1
• Budd-Chiari syndrome - presents with abdominal pain, distension, jaundice, and ascites 4
• Peritoneal tuberculosis - important differential in endemic areas, diagnosed by ascitic fluid ADA and peritoneal biopsy 2

Critical Management Steps

Initiate empirical antibiotics immediately after obtaining ascitic fluid if SBP is suspected - each hour of delay increases in-hospital mortality by 3.3%. 1 Do not wait for culture results, as mortality was historically >90% but has been reduced to approximately 20% with early treatment. 1

Common Pitfalls to Avoid

• Do not delay paracentesis - it should be performed in all patients hospitalized with ascites, even without obvious infection symptoms 1
• Do not be falsely reassured by absence of symptoms - up to one-third of SBP patients are asymptomatic or present only with encephalopathy 1
• Do not assume obesity or body habitus precludes accurate examination - ultrasound can detect ascites as small as 100 mL when physical examination is equivocal 1
• Do not withhold paracentesis for coagulopathy - routine prophylactic fresh frozen plasma or platelets before paracentesis is not recommended, as severe hemorrhage occurs in only 0.2-2.2% of procedures 1

Prognostic Implications

Development of ascites in cirrhosis dramatically worsens prognosis, with 5-year survival dropping from 80% in compensated cirrhosis to 30% with ascites development. 2 This patient should be evaluated for liver transplantation given the poor prognosis associated with ascites and the young age. 2