Tuberculosis is a very rare cause of iritis. Most people are already known to have TB.
TB is rare in the Western world (although numbers are rising because of AIDS which makes people susceptible to TB). TB is common in the unindustrialized world.
| Malaise |
| Loss of weight |
| Cough, breathing difficulties |
TB affects the eye in only 2% of sufferers of TB -- so these symptoms are rare! The infection is a secondary infection (see below)
| Iritis (a specific form, called granulomatous iritis) |
| Decreased vision due to posterior uveitis (multifocal choroiditis, retinitis, vasculitis, optic nerve inflammation) |
| Nodules on eyelids |
| Infections of the tissue around the eye, including the tear glands and ducts |
| Decreased vision due to corneal opacity (interstitial keratitis) |
| Redness of the sclera (episcleritis, nodular scleritis) |
Infection by the bacterium Mycobacterium tuberculosis. In the immunosuppressed, other types of bacterium (M. bovis, M. avium, M. fortuitum) may cause infection.
Respiratory droplet spread from infected patient when the disease is active
| Primary infection - Usually causes a focus of infection in the lung |
| Secondary infection - May affect other parts of the lung, lymph nodes, abdomen (peritonitis), skin, meninges of brain, eye. |
| Chest X-ray - may show Ghon focus (shadow at the top of the lung) |
| Culture of sputum, urine for "acid fast bacilli" - this means that the bacteria stain in a certain way with certain dyes |
| Mantoux skin test |
Oral antibiotics -- Isoniazid, Ethambutol, Rifampcin, Pyridoxine -- for at least six months. Other antibiotics are used in resistant cases, which are common outside the industrialised world (probably due to over-use of antibiotics).
Steroids are sometimes used, somewhat controversially, in iritis caused by TB
| Public health measures, eg less crowding and proper sanitation |
| BCG vaccine |