Trachoma

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Introduction

  • Trachoma is an infection caused by an obligate intracellular bacterium, Chlamydia trachomatis
  • The organism is found in the conjunctival as well as corneal epithelium and is responsible for two different conditions:
    • Trachoma (a severe disease)
    • Inclusion conjunctivitis (milder)
  • Trachoma is commonly associated with poverty and unhygienic living conditions

Clinical features

  • Acute phase:
    • Irritable red eye
    • Mucopurulent eye discharge
    • Eyelid oedema, pain, photophobia in severe cases
  • Chronic phase:
    • Follicles on tarsal conjunctivae
    • Papillae
    • Superficial punctate keratitis
    • Pannus formation on superior cornea
  • End stage:
    • Eyelid scarring with trichiasis, entropion
    • Conjunctival scarring
    • Limbal scarring with Herbert's pits
    • Corneal scarring

Differential diagnoses

  • Other forms of infective conjunctivitis (especially viral)
  • Allergic/vernal conjunctivitis
  • Corneal scarring from other diseases

Complications

  • Trichiasis
  • Entropion
  • Corneal scarring

Investigations

  • Conjunctival scraping for microscopy
  • Immunofluorescence or ELISA test
  • Giemsa staining for trachoma inclusion bodies

Drug treatment

Topical:

  • Tetracycline ointment applied 4 times a day for 6 weeks

Systemic:

Erythromycin, tetracycline (not recommended for young children) or the newer antibiotics e.g. azithromycin as appropriate

Azithromycin

  • Adult: 500 mg orally once daily for 3 days
  • Child
    • over 6 months: 10 mg/kg (maximum 500 mg) orally once daily for 3 days;
    • over 6 months (body weight 15 - 25 kg) 200 mg once daily for 3 days;
    • body weight 26- 35 kg: 300 mg once daily for 3 days;
    • body weight 36 - 45kg: 400 mg once daily for 3 days

Surgical treatment

  • Indicated for the treatment of trichiasis, entropion, corneal scarring
  • Corneal graft, but entropion must be corrected first

Notable adverse drug reactions, contraindications and caution

  • Systemic tetracycline is contraindicated in young children

Prevention

  • SAFE strategy: Surgery for trichiasis, Antibiotics for active disease, Face washing and Environmental changes
  • Improve personal and public hygiene
  • Treat the whole community with topical or systemic antibiotics
  • Prompt surgery for trichiasis and entropion to prevent blindness from corneal scarring