Makindo Medical Notes

🦠 Cytomegalovirus (CMV) is a member of the Herpesviridae family. It often mimics EBV and toxoplasmosis clinically but is usually asymptomatic in immunocompetent hosts. ⚠️ In pregnancy and in immunocompromised patients, CMV can be severe and life-threatening.

📖 About

• Very common virus – >50% of adults are seropositive.
• Peak infection around age 30.
• Latency in monocytes and reactivation in immunosuppression.
• Most healthy people have mild or no symptoms.

🧬 Aetiology

• Double-stranded DNA virus in the Herpesviridae family.
• Found in saliva, urine, semen, breast milk, blood, cervical/vaginal secretions.
• Transmission via close contact, transfusion, transplant, vertical (transplacental).

⚠️ Clinical Features

• Asymptomatic in most healthy individuals.
• Mononucleosis-like illness:
• Malaise, headache, pharyngitis, cervical lymphadenopathy.
• Distinguishing feature: Monospot negative.

🧑‍⚕️ In Immunocompromised (esp. CD4 < 50)

• CMV pneumonitis, encephalitis, hepatitis, retinitis (“pizza pie retinopathy”).
• Colitis and oesophagitis – causes bloody diarrhoea, abdominal pain.
• Pancreatitis, adrenalitis → diabetes/adrenal dysfunction.
• Monitor with CMV DNA PCR viral load.

🤰 In Pregnancy (Congenital CMV)

• Occurs in ~1 in 800 pregnancies.
• Features: IUGR, hepatosplenomegaly, jaundice, thrombocytopenia.
• Severe: Microcephaly, periventricular calcifications, chorioretinitis, deafness, seizures.
• Leading infectious cause of congenital sensorineural hearing loss.

🔬 Investigations

• Bloods: Atypical lymphocytosis.
• Monospot: Negative (helps differentiate from EBV).
• Histology: “Owl’s eye” intranuclear inclusions.
• Serology: CMV IgM (recent infection), rising IgG titres.
• PCR: Detects CMV DNA – used in transplant and HIV patients for monitoring.
• Other labs: ↑ LFTs, ↑ amylase (if pancreatitis), cytopenias.

💊 Management

• Immunocompetent: Usually supportive only.
• Severe / immunocompromised / congenital CMV:
  • IV Ganciclovir 5 mg/kg 12-hourly.
  • Oral Valganciclovir (prodrug, better bioavailability) 900 mg BD × 14 days.
  • Foscarnet or Cidofovir if ganciclovir-resistant.
• Monitor viral load by PCR to assess treatment response.
• Side-effects: neutropenia, thrombocytopenia, renal toxicity, male infertility.

📌 Key Exam Tips

• CMV vs EBV: Both give “mono-like” picture, but EBV Monospot +ve / CMV Monospot –ve.
• CMV retinitis is an AIDS-defining illness (CD4 < 50).
• “Owl’s eye” inclusion is the buzzword histology finding.
• Congenital CMV → think microcephaly + periventricular calcifications.