1. Preliminary clinical diagnosis

• Exposure compatible with fecal-oral transmission: stay at a summer camp about 1 month before illness, consistent with HAV incubation.
• Typical sequence: prodromal fever, malaise, anorexia and nausea, followed by dark urine, jaundice, right-upper-quadrant discomfort, hepatomegaly, and marked aminotransferase elevation.
• ALT 1450 U/L and AST 980 U/L indicate acute hepatocellular injury; bilirubin 110 µmol/L explains jaundice and dark urine.
• This pattern closely matches acute HAV manifestations described in Sherris & Ryan's Medical Microbiology, p. 485.

• Test serum IgM anti-HAV to confirm acute hepatitis A. A positive IgM anti-HAV establishes the diagnosis in this clinical setting. Sherris & Ryan's Medical Microbiology, p. 486.
• Also obtain: CBC, ALP/GGT, direct bilirubin, albumin, glucose, creatinine/electrolytes, urinalysis, and PT/INR.
• Exclude other causes of acute hepatitis as appropriate: HBsAg and IgM anti-HBc, anti-HCV/HCV RNA, and consider anti-HEV IgM depending on local epidemiology.
• Assess urgently for acute liver failure: altered mental status/encephalopathy, hypoglycemia, rapidly rising bilirubin, or prolonged PT/INR.

2. Management approach and treatment principles

Immediate management

• Admit or observe in an infectious-disease/medical setting if clinically moderate, unable to maintain oral intake, dehydrated, vomiting, has significant comorbidity, or has abnormal coagulation.
• Monitor clinical state, hydration, urine output, mental status, bilirubin, ALT/AST, glucose, and especially PT/INR.
• Encourage oral fluids and adequate calories. Use IV fluids only if oral intake is inadequate or there is dehydration.
• Small frequent meals according to tolerance. There is no need for an unnecessarily restrictive diet.
• Antiemetic treatment if nausea/vomiting limits fluids or food.
• Rest during the symptomatic period, followed by gradual return to normal activity as tolerated.

Avoid

• Alcohol until clinical and biochemical recovery.
• Unnecessary medications, especially potentially hepatotoxic drugs or supplements, including excess paracetamol/acetaminophen.
• Self-medication and unproven “hepatoprotective” products.

Escalate urgently if any of the following develop

• Confusion, drowsiness, asterixis, or other encephalopathy
• Bleeding tendency, markedly prolonged INR/PT
• Hypoglycemia
• Persistent vomiting, dehydration, renal dysfunction
• Rapid clinical worsening or suspected fulminant hepatitis

3. Preventive measures

Specific prevention

• Hepatitis A vaccination is the main preventive measure. It is particularly relevant for travelers to endemic areas, close contacts during outbreaks, food handlers in outbreak contexts, people with chronic liver disease, men who have sex with men, people who use drugs, and other locally recommended risk groups.
• For susceptible close contacts exposed to this patient, give hepatitis A vaccine as post-exposure prophylaxis within 14 days of exposure.
• Add immune globulin for selected higher-risk people, particularly those who are immunocompromised or have chronic liver disease, according to local public-health guidance. CDC guidance states that vaccine or immune globulin can prevent HAV when administered within 2 weeks of exposure, as described in the CDC post-exposure recommendations.

Measures to prevent fecal-oral spread

• Notify local public-health/infection-control services according to jurisdictional rules.
• Rigorous handwashing with soap and water after toilet use and before preparing food.
• The patient should not prepare or serve food for others while infectious.
• Ensure safe drinking water, proper sewage disposal, and hygienic food preparation at camps and group settings.
• Clean potentially contaminated bathroom and frequently touched surfaces.
• Do not share towels or personal hygiene items.

1. General treatment principles in infectious diseases
   • Etiotropic therapy: treatment directed at the causative pathogen.
   • Pathogenetic therapy: correction of disease mechanisms such as dehydration, hypoxia, shock, electrolyte or acid-base disturbances.
   • Detoxification therapy: reducing effects of microbial toxins and metabolic products, mainly through fluids, organ support, and source control where needed.
   • Symptomatic therapy: relief of fever, pain, nausea, cough, pruritus, and other symptoms.
2. Acute hepatitis B
   • Incubation and prodromal manifestations.
   • Anicteric form: nonspecific systemic symptoms and elevated aminotransferases without visible jaundice.
   • Icteric form: dark urine, jaundice, hepatomegaly, possible cholestatic manifestations, and biochemical abnormalities.
   • Fulminant hepatitis: acute hepatic failure with coagulopathy and encephalopathy, higher risk with severe immune-mediated hepatocyte injury and certain coinfections.
3. Laboratory diagnosis
   • The likely intended two-step protocol is screening by ELISA followed by a confirmatory assay, but the appropriate test depends on whether this concerns HBV, HIV, or another infection. For acute HBV, key markers include HBsAg, anti-HBc IgM, HBeAg, anti-HBs, and HBV DNA.