What is the most likely type of viral hepatitis in a pediatric patient presenting with intermittent fever, vomiting, diarrhea, diffuse abdominal pain, jaundice, scleral icterus, and a palpable liver 5 cm below the costal margin, with symptoms progressing over the past week?

Hepatitis A (Answer: A)

The most likely diagnosis is Hepatitis A virus infection, given the pediatric presentation with fever, vomiting, diarrhea, abdominal pain, jaundice, scleral icterus, and significant hepatomegaly (5 cm below costal margin) over a one-week timeframe. 1, 2

Clinical Reasoning

Age-Dependent Presentation Matches Hepatitis A

• Children under 6 years have >90% asymptomatic infections with Hepatitis A, but when symptomatic, they present with the exact constellation seen here: fever (96% of cases), abdominal pain (78%), vomiting (47%), and jaundice (80%). 1, 2
• The progression from prodromal symptoms (fever, vomiting, diarrhea, abdominal pain) to jaundice over approximately one week is classic for Hepatitis A, where jaundice typically appears within 1-7 days after initial symptoms. 1, 3
• Hepatomegaly is found in 74% of pediatric Hepatitis A cases, and the 5 cm enlargement below the costal margin with tenderness is characteristic. 2

Timeline Excludes Other Hepatitis Types

• Hepatitis A has a mean incubation period of 28 days (range 15-50 days) with abrupt onset, which fits the acute one-week presentation. 1, 3
• Hepatitis B, C, and D typically have longer incubation periods and more insidious onset, making them less likely with this acute presentation. 4
• The combination of gastrointestinal symptoms (diarrhea, vomiting) preceding jaundice by several days is most characteristic of Hepatitis A. 3, 5

Epidemiologic Considerations

• Hepatitis A accounts for 85% of acute viral hepatitis cases in pediatric populations in endemic areas. 6
• The fecal-oral transmission route of Hepatitis A makes it the most common cause of acute hepatitis in children, particularly in areas with inadequate sanitation. 1, 6
• Hepatitis A is the most important vaccine-preventable disease for travelers, with international travel accounting for >25% of cases in children under 15 years. 1

Key Diagnostic Features Present

• Dark urine (bilirubinuria) typically precedes jaundice by 1-7 days in Hepatitis A, consistent with the 2-day history of yellowish discoloration. 1, 3
• Scleral icterus with jaundice indicates significant hyperbilirubinemia, which occurs in 80% of symptomatic pediatric Hepatitis A cases. 2
• The mild fever (38.0°C) with stable vital signs is typical for uncomplicated Hepatitis A, as opposed to more severe presentations seen with fulminant hepatitis. 3

Common Pitfalls to Avoid

• Do not assume all pediatric hepatitis is asymptomatic—while 90% of Hepatitis A infections in children <6 years are asymptomatic, the remaining 10% present with classic icteric disease as seen here. 1
• Hepatitis A can present with prominent gastrointestinal symptoms that may initially suggest gastroenteritis, but the development of jaundice and hepatomegaly distinguishes it. 2, 5
• Rare extrahepatic manifestations (rash, arthralgias) can occur but are uncommon; the classic presentation as described here is most typical. 5

Immediate Next Steps

• Confirm diagnosis with anti-HAV IgM antibodies, which are present in almost all patients at symptom onset (though rare cases may require repeat testing if initially negative). 5
• Monitor liver function tests (ALT, AST, bilirubin) and coagulation studies to assess severity and rule out fulminant hepatitis. 3, 6
• Provide supportive care with monitoring for complications, as nearly all pediatric patients with Hepatitis A experience complete clinical recovery within 6 months. 3