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Tuberculosis is a chronic infectious and communicable granulomatous disease caused by the Mycobacterium tuberculosis. Tuberculosis most commonly affects the lungs (PTB) but can also affect any part of the body for example- the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, bones, joints and even the skin.

Causative agent-Mycobacterium tuberculosis (MTB), is a slow-growing aerobic bacterium that divides every 16 to 20 hours; this is extremely slow compared to other bacteria, which have division times measured in minutes.

Source of infection-human and bovine. The most common source of infection is human, whose sputum is positive for tubercle bacilli and who has either receive no treatment or not been treated fully. The bovine source of infection is usually infected milk.

Faeces,urine,pus,pleural and peritoneal fluids, gastric contents in extra pulmonary tuberculosis

Communicability: Patients are infective as long as they remain untreated, effective anti-microbial treatment reduces infectivity by 90% within 48 hours.

Host factors: a) Age: Tuberculosis affects all ages.

b) Sex: More common in males.

Incubation period: weeks, months or even years

TB is spread by droplets expelled by people with the active disease of the lungs when they cough, sneeze, speak, kiss, spit

The chain of transmission can be broken by isolating patients with active disease and starting effective anti-tuberculous therapy.

( transplancental, ingestion, inoculation,)

Smoking more than 20 cigarettes a day also increases the

risk of TB by two- to four-times. Immunocompromise patient for example, AIDS, those

undergoing chemotherapy,The risk of TB increases with the frequency of contact

with people who have the disease, with crowded or unsanitary living conditions and with poor nutrition.

Others at risk include those from areas where TB is common, health care workers who serve high-risk clients, medically under served, low-income population, children exposed to adults in high-risk categories

A productive, prolonged cough of more than three weeks duration,

chest pain and coughing up blood. Systemic symptoms include fever, chills, night

sweats, appetite loss, weight loss and anemia, easily fatigued.

Extra pulmonary forms are more common in immunosuppressed persons and in young children.

A medical history a chest X-ray A physical examination Sputum for AFB – 3 specimen (morning) Tuberculin skin test/Mantoux

The Mantoux test is carried out by injecting intradermally on the flexor surface of the forearm 1 Tuberculin Unit of PPD in 0.1ml. The result of the test is read after 72 hours. Reaction exceeding 10 mm (induration )are considered positive. A positive reaction indicates that the person is infected with M. tuberculosis, it does not prove that the person is suffering from the disease.

Anti-tuberculosis drugs: It should be highly effective, free from side effects, easy to administer, and reasonably cheap. The currently used drugs may be classified into two groups: bactericidal and bacteriostatic.

Bactericidal drugs

1. Rifampicin: 10 mg/kg body weight. Side effect-red urine, hepatitis

2. Isoniazide (INH): single daily dose of 5 mg/kg body weight . Side effect hepatis & peripheral neuropathy

3. Streptomycin: the daily dose is 15 gm in a single dose. Side effect - ototoxicity

4. Pyrazinamide: 25 mg/kg body Side effect - joint pains & hepatitis

Bacteriostatic drugs

1. Ethambutol: 15 mg/kg body weight in 2-3 doses per day. Its major side effect is optic neuritis.

2. Thioacetazone: the usual adult dose is 2 mg/kg body weight. Side effects include GI disturbance, blurring of vision, hemolytic anemia and urticaria.

TREATMENT

First Line Drugs: Rifampicin Isoniazid Ethambutol Streptomycin Pyrazinamide

Second Line Treatment: Ethionamide Ciprofloxacin/Ofloxacin Cycloserine Kanamycin Para-aminosalicylic acid.

Patient swallows the medications under the watchful eye of a reliable person – doctors, nurse, health worker, community volunteer for the duration of 6-9 months.

By this method 100% cure of the patients is expected, if the patient takes the drugs without fail.

It is free of cost in all health facilities working for the National TB control program.

First phase or initial phase: During this intensive phase, three or more drugs are combined to kill off as many bacilli as possible. The drug include INH, Rifampicin, pyrazinamide and streptomycin or ethambutol for a period of 2 months

The second or continuation phase: aimed to kill the persisting bacilli, followed by 2 drugs in continuation phase, INH and rifampicin or thioacetazone, given daily for 6 months.

TB treatment Category

TB patient Alternative TB RegimenInitial Phase Continuation

Phase1 New Smear positive PTB

& seriously ill extra pulmonary TB or smear negative pulmonary TB [severe PTB]

2HRZE 6HE

2 Sputum smear positive ;Relapse, treatment failure & return after default

2SHRZE/1HRZE

5HRE

3 Smear negative PTB & extra pulmonary TB [less severe]

2HRZ 6HE

TreatmentH – IsoniazideR – RifampicinS – StreptomycinZ – PyrazinamideE – Ethambutol T – Thiacetazone

Multi drug resistance

Isoniazid : REZ for 9 – 12 months Rifampicin : HE for 18 months If both HR : EZ +quinolone for 9 -12 months

+inj. Streptomycin or amikacin for first 4 – 6 months

pleural EffusionPneumothoraxEmpyemaMiliary TBLung Abscess

A BCG vaccination: BCG is the only widely used live bacterial vaccine. It consists of living bacteria derived from an attenuated bovine strain of tubercle bacilli.

for protection of infants and young children from serious forms of tuberculosis, such as TB meningitis and miliary TB

for routine use at birth in countries with high TB prevalence

protection from serious form of TB doesn’t extend to adults

given immediately after birth under EPI

Dosage: 0.1 mg given intradermally

Table 1. Routine immunisation schedule. Vaccine Diseases Age

BCG Tuberculosis At birth

DPT Diphteria, Pertussis, Tetanus

6, 10, 14 weeks

OPV Polio At birth, 6, 10, 14 weeks

Measles Measles 9 months