Makindo Medical Notes

🦠 Herpes simplex virus (HSV): HSV-1 is transmitted mainly via oral contact 💋, HSV-2 mainly via sexual contact ⚤. Most primary infections are asymptomatic, making infection control challenging.

🔎 Herpes Viruses

• Two main types: HSV-1 and HSV-2 with overlapping but distinct pathogenicity.
• Cause a wide range of diseases: brain 🧠, oral 👄, genital ⚤, ocular 👁️.
• Characteristic feature: recurrent vesicles and ulceration.

🧬 Structure

• Unique four-layered viral structure:
• 📦 Core: large, double-stranded DNA genome.
• ⬡ Icosahedral capsid of capsomers.
• 🧩 Tegument: amorphous protein coat.
• 🧪 Envelope: lipid bilayer with glycoproteins (key for entry & immune evasion).

🧫 Microbiology

• Member of the alpha-herpesvirus group.
• Enveloped virus, ~160 nm in diameter.
• Genome: linear, double-stranded DNA.

📌 Transmission

• HSV-1: kissing, saliva exchange 💋.
• HSV-2: sexual contact ⚤ (seroprevalence ~23% in UK/US adults).

👄 HSV-1 Clinical Features

• Herpes stomatitis: painful oral ulcers, fever, lymphadenopathy 🤒.
• Herpetic whitlow: vesicles on fingers of healthcare workers 👩‍⚕️.
• Keratoconjunctivitis: dendritic corneal ulcers (fluorescein stain ✨).
• HSV encephalitis: haemorrhagic necrosis of temporal lobe → seizures, confusion 🧠⚡.
• Disseminated infection (immunocompromised): pneumonitis, oesophagitis, hepatitis, colitis, widespread skin disease.

⚤ HSV-2 Clinical Features

• Genital herpes: painful vesicles, dysuria, tender inguinal nodes.
• Anorectal infection: proctitis, ulcers.
• Neonatal HSV: 70% due to HSV-2 👶 — can cause disseminated, CNS, or skin/eye/mouth disease.

🧪 Diagnosis

• Viral culture: gold standard in acute cases.
• PCR: high sensitivity for CSF (encephalitis) or serum.
• Serology: useful in defining prior exposure.

💊 Treatment

• First-line antivirals: aciclovir, valaciclovir, famciclovir.
• Mild disease: Aciclovir 200 mg PO five times daily × 5 days.
• Severe disease (encephalitis, neonatal, disseminated): IV aciclovir 10 mg/kg every 8 hours.
• Supportive care: hydration, analgesia, topical therapy for ocular disease (ophthalmology referral 👁️).

💡 Clinical Pearls

• HSV-1: usually oral, but now a leading cause of genital herpes in younger populations.
• HSV encephalitis = always treat empirically with IV aciclovir if suspected 🚨.
• Neonatal herpes carries high mortality → prevention & early treatment critical 👶.

📚 References

• Herpes Simplex Microbiology – NCBI
• BNF – Aciclovir