TUBERCULOSIS LEC 2
DR HADEEL FADHIL
@Guidelines for determining a positive tuberculin skin test reaction
Induration >5 mm:
() HIV-positive persons
() Recent contacts of TB case
() Fibrotic changes on chest radiograph consistent with old TB
() Patients with organ transplants and other immunosuppressed patients (receiving the equivalent of >15 mg/d Prednisone for >1 mo):
Induration >10 mm
() Recent arrivals (<5 yr) from high-prevalence countries.
() Injection drug users.
() Residents and employees of high-risk congregate settings: prisons , nursing homes and other health care facilities, residential facilities for AIDS patients, and homeless shelters.
() Mycobacteriology laboratory personnel.
() Persons with clinical conditions that make them high-risk: silicosis , diabetes mellitus, chronic renal failure, some hematological disorders (e.g., leukemia s and lymphomas), other specific malignancies (e.g., carcinoma of the head or neck and lung), weight loss of >10 percent of ideal body weight, gastrectomy, jejunoileal bypass
() Children <4 yr of age or infants, children, and adolescents exposed to adults in high-risk categories
Induration >15 mm
() Persons with no risk factors for TB
Methods of control of TB:
A- Preventive measures:
1- Promptly identify diagnosis & treat potentially infectious patients with TB disease (establish case finding & treatment facilities) to reduce transmission.
2- Make available medical, laboratory & X-ray facilities for prompt examination of patients, contact & suspect.
Provide public health nursing & out reach services for direct supervision of patient therapy & arrange for examination & preventive treatment of contact.
3- Educate the public in mode of spread & methods of control & the importance of early diagnosis.
4- Reduce or eliminate those social conditions that increase risk of infection.
5- TB control programs should be established in all institutional setting in which health care is provided.
6- Use preventive treatment with isoniazide which effective in preventing the progression of latent TB infection to TB disease in a high proportion of individuals.
Preventive therapy is routinely indicated for infected persons under 35 years of age (its important to rule out active TB disease before starting preventive therapy especially in immuncomprimised patients). Because of the increase risk of INH associated hepatitis with increasing age so:
INH is not routinely advised for persons with TB infection over 35 years unless one or more of the followings is present:
*recent infection.
*close or household association with current cases.
*abnormal chest X-ray consistent with old healed TB disease.
*DM
*silicosis
*prolonged therapy with CS
*HIV infection.
INH preventive therapy is contraindicated in:
1- There is history of previous severe adverse reaction to the drug.
2- Acute liver disease of any etiology.
3- During pregnancy.
4- Persons who use alcohol regulary.
5- Those with chronic liver disease & persons with hepatitis C infection (may be at increased risk of INH toxicity).
7- If HIV with TST with 5 mm or more of induration & active TB disease has been ruled out, we should start the prophylaxis.
8- BCG immunization:
Bacillus Calmette-Guérin (BCG) vaccines are live attenuated vaccines.
These vaccines are largely used in prevent tuberculosis.
BCG is given as early as possible in life preferably at birth, the vaccine is injected intradermally usually on the upper portion of the left arm at the dose of 0.05 ml for these aged 0-1 year & 0.1 ml for those aged more than 1 year.
BCG has a 20-60% efficacy but it appear to be most effective in preventing disseminated disease, including TB meningitis in children.
BCG is included in the expanded program on immunization in Iraq.
BCG also indicated in:
@health care worker at high risk .
@immigrants from countries where TB is high prevalent.
@group of high risk for HIV infection.
BCG is contraindicated in people with immunodeficiency diseases including HIV infection.
9- Elimination bovin TB by pasteurize or boil milk.
10- Take measure to prevent silicosis among those working in industrial plants.