Chapter 28: Infections – Viral CNS, GI, Ocular, Hepatic & Miscellaneous

🧠 Enterovirus · HSV · Arbovirus · Rabies · Rotavirus · Norovirus · Adenovirus · Hepatitis A-E · EBV · CMV · Molluscum · Warts · EBV · HIV · Dengue · Zika
Forfar & Arneil's Textbook of Pediatrics – Comprehensive coverage: diagnosis, management, prevention, and emerging viral threats.

📖 Key topics: viral CNS, GI, ocular, hepatic, miscellaneous viruses

🧠 Viral CNS infections
Enterovirus (most common meningitis), HSV-1 (encephalitis – temporal lobe), VZV, measles/SSPE, arboviruses (West Nile, Japanese encephalitis), rabies (hydrophobia, fatal). Diagnosis: CSF PCR. Treatment: acyclovir (HSV), supportive for enterovirus.
🤢 GI viruses
Rotavirus (severe dehydrating diarrhea in infants; vaccine available), Norovirus (outbreaks, vomiting), Adenovirus 40/41, Astrovirus, Sapovirus. Treatment: rehydration (oral/IV), supportive. Hand hygiene crucial.
👁️ Ocular viral infections
Adenovirus (epidemic keratoconjunctivitis – highly contagious), HSV (keratitis – dendritic ulcer), VZV (herpes zoster ophthalmicus), CMV retinitis (immunocompromised). Treatment: supportive or antivirals (acyclovir, ganciclovir).
🫀 Viral hepatitis
HAV (fecal-oral, self-limited, vaccine), HBV (perinatal, chronic, vaccine), HCV (perinatal, chronic, treat with direct-acting antivirals), HDV (co-infection with HBV), HEV (enteric, pregnant high risk).
🦟 Miscellaneous viruses
Dengue (breakbone fever, hemorrhagic fever, shock syndrome), Chikungunya (arthritis), Zika (congenital microcephaly, Guillain-Barré), EBV (mononucleosis, PTLD), Parvovirus B19 (fifth disease, aplastic crisis).
⚠️ Emergency red flags: Viral encephalitis – focal seizures, altered mental status → HSV PCR, start acyclovir. Severe dengue warning signs: persistent vomiting, mucosal bleeding, abdominal pain, hepatomegaly, rising HCT → IV fluids.

🧠 Approach to suspected viral CNS infection

1
Lumbar puncture + CSF studies – cell count (lymphocytic pleocytosis), protein, glucose, PCR for HSV, enterovirus, VZV, CMV, and arboviruses (if epidemiologic risk).
2
Empiric acyclovir – for suspected HSV encephalitis (temporal lobe signs, focal seizures, altered sensorium) while awaiting PCR.
3
Supportive care – ICP monitoring, seizure control, rehydration; no specific antiviral for enterovirus or arboviruses.
4
Rabies – history of animal bite (bat, dog). Post-exposure prophylaxis: wound cleaning, rabies vaccine, immune globulin. Once symptoms begin, almost universally fatal.

🤢 Viral gastroenteritis & hepatitis management

💧
Gastroenteritis (rotavirus/norovirus) – Oral rehydration solution (ORS) first line. IV fluids for severe dehydration. No antidiarrheals; zinc supplementation reduces duration. Rotavirus vaccine (RotaTeq, Rotarix) prevents severe disease.
🩸
Viral hepatitis (HAV) – supportive; prevention by vaccine + good hygiene.
🩸
Hepatitis B – universal infant vaccine. Chronic infection: monitor ALT, viral load; antivirals (tenofovir, entecavir) for active disease.
🩸
Hepatitis C – screen at-risk; direct-acting antivirals (pangenotypic) now approved for children ≥3 years.
🦟
Dengue fever – supportive; avoid NSAIDs (risk of bleeding). Recognize warning signs of shock (IV fluid resuscitation critical).

🧠 Reflex prompts – key clinical pearls

🧠 5-year-old with fever, headache, vomiting, and temporal lobe seizures. Most likely virus?
HSV-1 encephalitis. Start acyclovir immediately, confirm with CSF PCR.
🤢 Infant with severe watery diarrhea ×3 days, dehydration. Rotavirus suspected. Prevention?
Rotavirus vaccine (oral, 2 or 3 doses).
👁️ Child with red eye, photophobia, foreign body sensation, preauricular lymphadenopathy. Likely?
Adenoviral keratoconjunctivitis. Highly contagious; supportive care.
🩸 Child with jaundice after eating raw shellfish. Likely hepatitis?
Hepatitis A (fecal-oral, self-limited). Supportive care; vaccine prevented.
🦟 Child from endemic area with fever, retro-orbital pain, myalgia, petechiae, rising hematocrit. Likely?
Dengue fever with warning signs (risk of dengue shock). IV fluids, monitor.
🧬 Hepatitis B prevention in newborns of HBsAg-positive mothers?
Hepatitis B vaccine + HBIG within 12 hours of birth.
🐕 Child bitten by a stray dog with foaming mouth. Next step?
Immediate wound cleaning, rabies vaccine + immune globulin (HRIG).
🤢 Most common cause of viral gastroenteritis in children under 5 years worldwide?
Rotavirus (now reduced by vaccination).
🦠 Which virus causes epidemic keratoconjunctivitis (EKC)?
Adenovirus serotypes 8, 19, 37.
💉 Chronic hepatitis C in children: treatment?
Direct-acting antivirals (sofosbuvir/ledipasvir, glecaprevir/pibrentasvir).