TUBERCULOSIS

BY KHKULA IMTIAZ

Epidemiology:

• Tuberculosis is the most common cause of death world wide from a single infectious disease and is on the increase in most parts of the world.

• The reasons for this are primarily inadequate programmes for disease controlMultiple drug resistance ImmunosuppressionRapid rise in the world population

Tuberculosis:

• Tuberculosis commonly known as TB, is a contagious and often severe air born disease that is caused by mycobacterium tuberculosis.

• TB germs are most commonly found in the lungs, but sometimes they can move to other parts of the body.

Spread of TB germs:

Predisposing factors:

Chronic debilitating disorders,Drug abuse,Prolonged corticosteroid medication,AIDS and other disorders resulting in reduced

defense mechanisms.

Pathology:Primary tuberculosis: The initial infection occur in the upper region

of the lung producing a subpleural lesion called the Ghon focus.This may also occur in GI tract.

The primary focus is characterized by granulomatous lesions,which consist of central areas of caseation surrounded by epitheliod cells and gaint cells.

Secondary lesion: If resistance to the original infection is low,

widespread dissemination via the blood stream may occur, giving rise to miliary tuberculosis or meningitis. More often, blood spread occurs months or years later and bacilli are deposited in extrapulmonary tissues.

Tertiary lesion: Bones or joints are affected in about 5 ٪

of patients with tuberculosis. There is a predilection for the vertebral bodies and the large synovial joints.

Clinical features:Cough (2-3 weeks or more)Coughing up bloodChest painsFeverNight sweatsFeeling weak and tiredLosing weight Decreased or no appetiteIf you have TB outside the lungs, you may have

other symptoms

Investigations:The ESR: is increased.CBC: relative lymphocytosis.The mantoux or Heaf test: will be positive.If synovial fluid is aspirated, it may be cloudy, the

protein concentration is increased and the white cell count is elevated.

Acid-fast bacilli are identified in synovial fluid in 10-20 ٪ of cases, and cultures are positive in over half.

A synovial biopsy is more reliable; sections will show the characteristic histological features, and acid fast bacilli may be identified; cultures are positive in over 80 ٪ of cases.

Bronchoscopychest X-ray

Management: Chemotherapy : The most effective treatment is a

combination of antituberculous drugs, which should always include rifampicin and isoniazid.

A recommended regimen is rifampicin, isoniazide and ethambutol ( or pyrazinamide ) for 8 weeks, and thereafter rifampicin and isoniazide for a further 6-12 months.