TRACHOMA

Pathogenesis: 

1. Causative organism: Chlamydia trachomatous  seotypes A, B, Ba and C.

2. They reside inside cells which make them immune from affect of drugs

3. cell-mediated delayed hypersensitivity (Type IV) reaction to the intermittent presence of chlamydial antigen

Clinical features:

symptoms: foreign body sensation, lacrimation, photophobia

signs:

1. Congestion

2. Papillae

3. Follicles

4. Typical star-shaped scarring is seen at the centre of the follicles 

5. Arlt’s line—A line of palpebral conjunctival scarring is seen 2 mm from the upper lid margin.

cornea

1. superficial keratitis

2. Herbets pits are follicles near limbus. later they become depressions.

3. pannus is lymphoid infilteration with vascularization near the upper part of cornea. IN Progressive pannus Superficial blood vessels are parallel and directed downwards. They extend to a horizontal level beyond which zone of infiltration and haze is present. In  Regressive pannus the area of infiltration stops short and the blood vessels extend beyond this haze. This is important in evaluating the result of treatment and progress of disease

WHO classification

1. TF (Trachomatous inflammation—Follicular)

 At least five or more follicles (each 0.5mm or more in diameter) should be present on the

upper tarsal conjunctiva.

2. TI (Trachomatous inflammation—Intense)

 There is marked inflammatory thickening of the upper tarsal conjunctiva which appears red, rough, thickened with numerous follicles. This obscures 50% or more of the deep tarsal vessels.

3. TS (Trachomatous scarring)

Presence of scarring is seen in the upper tarsal conjunctiva. Which is seen as white fibrous lines, bands or sheets.

4. TT (Trachomatous trichiasis)

 Atleast one or more misdirected eyelashes rub against the eyeball.

5. CO (Corneal opacity)

Complications:

1. trichiasis

2. corneal ulcer

3. entropion

4. corneal opacity

5. Xerosis—Scarring of conjunctiva results in destruction of goblet cells which secrete mucus

6. Ptosis due to large follicles

7. blindness due to perforation of corneal ulcer

Treatment: 

The SAFE strategy for trachoma involves

1.  Surgery for trichiasis, 

2. Antibiotics for active disease, 

   1. Topical tetracycline 1%  ointment three times a day for one month

   2. systemic azithromycin 20mg/kg body weight upto 1 gram per oral 

3. Facial hygiene and 

4. Environmental improvement.