Trachoma

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  • Trachoma
    • a chronic keratoconjunctivitis
    • primarily affecting the superficial epithelium of conjunctiva and cornea simultaneously.
    • It is characterised by a mixed follicular and papillary response of conjunctival tissue.
    • one of the leading causes of preventable blindness in the world.
  • Etiology
    • caused by a Bedsonian organism, the Chlamydia trachomatis
      • belong to the Psittacosis-lymphogranuloma- trachoma (PLT) group.
      • organism is epitheliotropic
      • produces intracytoplasmic inclusion bodies called H.P. bodies (Halberstaedter Prowazeke bodies) (MCQ)
      • Serotypes A, B, Ba and C are associated with hyperendemic (blinding) trachoma
      •  serotypes D-K are associated with paratrachoma (oculogenital chlamydial disease).
    • Predisposing factors
      • infection is usually contracted during infancy and early childhood
      • preponderance exists in the females both in number and in severity of disease.
      • more common in areas with dry and dusty weather.
      • More common in poor classes owing to unhygienic living conditions
      • outdoor workers are more affected in comparison to office workers.
    • Source of infection
      • the main source of infection is the conjunctival discharge of the affected person..
      • Modes of infection
        • Direct spread through contact by air-borne or water-borne modes.
        • Vector transmission is common through flies.
        • Material transfer through contaminated fingers of doctors, nurses and contaminated tonometers , surma-rods
  • Clinical profile of trachoma
    • Incubation period 5-21 days.
    • Natural history.
    • development of acute disease occur in the first decade of life
    • sequelae occur at least after 20 years of the disease.
    • peak incidence of blinding sequelae is seen in the fourth and fifth decade of life.
  • Signs
    • Conjunctival signs
      • Congestion of upper tarsal and forniceal conjunctiva.
      • Conjunctival follicles.
        • Follicles  look like boiled sagograins
        • commonly seen on upper tarsal conjunctiva and fornix;
      • follicles may be seen on the bulbar conjunctiva (pathognomic of trachoma). (MCQ)
      • Structure of follicle.
        • Follicles are formed due to scattered aggregation of lymphocytes and other cells in the adenoid layer.
      • Leber cells
        • Central part of each follicle is made up of mononuclear histiocytes, few lymphocytes and large multinucleated cells
      • Presence of Leber cells and signs of necrosis differentiate trachoma follicles from follicles of other forms of follicular conjunctivitis.(MCQ)
      • Papillary hyperplasia.
        • Papillae are reddish, flat topped raised areas
        • give red and velvety appearance to the tarsal conjunctiva
        • Each papilla consists of central core of numerous dilated blood vessels surrounded by lymphocytes and covered by hypertrophic epithelium.
      • Conjunctival scarring
        • irregular, star-shaped or linear.
        • Linear scar present in the sulcus subtarsalis is called Arlt’s line (MCQ)
      • Concretions
      • formed due to accumulation of dead epithelial cells and inspissated mucus in the depressions called glands of Henle.
    • Corneal signs
      • Superficial keratitis may be present in the upper part.
      • Herbert follicles
        • refer to typical follicles present in the limbal area
      • Pannus
        • infiltration of the cornea associated with vascularization is seen in upper part
        • The vessels are superficial and lie between epithelium and Bowman’s membrane.
        • Later on Bowman’s membrane is also destroyed.
        • Pannus may be progressive or regressive.
      • Herbert pits
        • oval or circular pitted scars, left after healing of Herbert follicles in the limbal area
      • Corneal opacity
  • Grading of trachoma
    • McCallan’s classification (MCQ)
    • Stage I (Incipient trachoma or stage of infiltration).
    • Stage II (Established trachoma or stage of florid infiltration).
    • Stage III (Cicatrising trachoma or stage of scarring).
    • Stage IV (Healed trachoma or stage of sequelae).
    • WHO classification
      • TF: Trachomatous inflammation-follicular
      • TI : Trachomatous inflammation intense.
      • TS: Trachomatous scarring
      • TT: Trachomatous trichiasis.
      • CO: Corneal opacity
  • Sequelae of trachoma
    • Sequelae in the lids may be trichiasis, entropion, tylosis (thickening of lid margin), ptosis, madarosis and ankyloblepharon.
    • The clinical diagnosis of trachoma is made from its typical signs; at least two sets of signs should be present out of the following:
      • Conjunctival follicles and papillae
      • Pannus progressive or regressive
      • Epithelial keratitis near superior limbus
      • Signs of cicatrisation or its sequelae
  • Differential diagnosis
    • Trachoma with follicular hypertrophy must be differentiated from acute adenoviral follicular conjunctivitis (epidemic keratoconjunctivitis) as follows :
      • Distribution of follicles
        • in trachoma is mainly on upper palpebral conjunctiva and fornix
        • in EKC lower palpebral conjunctiva and fornix is predominantly involved.
    • Trachoma with predominant papillary hypertrophy needs to be differentiated from palpebral form of spring catarrh as follows:
      • in spring catarrh.
        • Papillae are large in size
        • usually there is typical cobble-stone arrangement
      • pH of tears
        • usually alkaline in spring catarrh,
        • while in trachoma it is acidic,
      • Discharge is ropy in spring catarrh.
      • In trachoma, there may be associated follicles and pannus.
  • Management
    • Treatment of active trachoma
    • Topical therapy regimes.
      • 1 percent tetracycline or 1 percent erythromycin eye ointment for 6 weeks or
      • 20 percent sulfacetamide eye drops along with 1 percent tetracycline eye ointment for 6 weeks.
    • The continuous treatment for active trachoma should be followed by an intermittent treatment especially in endemic or hyperendemic area.
    • Systemic therapy regimes.
      • Tetracycline
      • erythromycin
      • doxycycline
      • azithromycin
    • Combined topical and systemic therapy regime
  • Prophylaxis
    • Hygienic measures.
      • The use of common towel, handkerchief, surma rods etc. should be discouraged.
      • A good environmental sanitation will reduce the flies.
      • A good water supply would improve washing habits.
    • Early treatment of conjunctivitis.
    • Blanket antibiotic therapy (intermittent treatment
      • The regime is to apply 1 percent tetracycline eye ointment twice daily for 5 days in a month for 6 months.

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