Makindo Medical Notes

Donovanosis is a sexually transmitted infection that requires early recognition and treatment to prevent complications.

About

• Sexually transmitted infection that can cause chronic ulcers.

Aetiology

• Caused by Calymmatobacterium granulomatis, also known as Klebsiella granulomatis comb nov.

Clinical

• The first sign of infection is usually a firm papule or subcutaneous nodule that later ulcerates. Four types of Donovanosis are classically described:
  • Ulcerogranulomatous: The most common variant; non-tender, fleshy, exuberant, single or multiple, beefy red ulcers that bleed readily when touched.
  • Hypertrophic or verrucous type: An ulcer or growth with a raised irregular edge, sometimes with a walnut-like appearance.
  • Necrotic: Usually a deep foul-smelling ulcer causing tissue destruction.
  • Sclerotic: Involves extensive fibrous and scar tissue formation.
• Genitals are affected in 90% of cases and the inguinal area in 10%. Extragenital cases occur in about 6% of cases, with sites including the lip, gums, cheek, palate, and pharynx.
• Lymphadenitis is uncommon, and dissemination is rare but can affect the liver and bones, especially in pregnancy and cervical lesions.
• Lesions tend to grow more rapidly during pregnancy. A biopsy should be done if ulcers do not respond to antibiotics to rule out squamous cell carcinoma.

Investigations

• Giemsa stain: Tissue smears prepared from ulcer material can reveal large mononuclear cells with intracytoplasmic cysts filled with deeply stained Gram-negative Donovan bodies.
• Histologic examination: Giemsa or Silver stains reveal chronic inflammation with plasma cells and polymorphonuclear leukocytes. Donovan bodies are pleomorphic and sized 1-2 0.5-0.7 μm.
• PCR methods: Useful for diagnosing C. granulomatis but are not commercially available. Includes in-house nucleic acid amplification tests.
• Culture: Rarely performed and only available in specialized laboratories.
• Serology: Has been used historically but is not reliable or routinely available.

Management

• First-line treatment: Azithromycin 1 g weekly or 500 mg daily orally.
• Alternative regimens:
  • Co-trimoxazole 160/800 mg twice daily orally.
  • Doxycycline 100 mg twice daily orally.
  • Erythromycin 500 mg four times daily orally, recommended in pregnancy.
  • Gentamicin 1 mg/kg every 8 hours parenterally can be used as an adjunct if lesions are slow to respond.
• Treatment in pregnancy: Erythromycin 500 mg four times daily orally or Azithromycin 1 g weekly.
• Treatment of children: Azithromycin 20 mg/kg orally once daily.
• Prophylaxis in neonates: Consider Azithromycin 20 mg/kg once daily for three days for neonates born to mothers with genital lesions.
• Partner management: Due to the absence of reliable screening tests and the long incubation period, all sexual contacts of cases in the last six months should be clinically examined for lesions.

References

• 2018 UK national guideline for the management of donovanosis