Tuberculosisis a chronic bacterial infection caused by a group of bacteria, Mycobacteriaa, the most common of which is Mycobacterium tuberculosis. Less frequently, it can be caused by Mycobacterium bovis and Mycobacterium africanum. The clinical picture is quite variable and dependens on the specific organ affected by the disease. Although the lung is the most commonly affected organ, almost all parts of the body can be infected with this bacterium. HIV infection has now become one of the most important risk factors for the development of active tuberculosis.

Diagnosis:

Smear microscopy remains the most important diagnostic tool. Histo-pathology and radiography are also helpful, particularly in those patients who do not produce sputum.

Treatment:

The treatment of tuberculosis has now been standardized by putting patients into different categories based on the smear status, seriousness of the illness and previous history of treatment for TB. Accordingly, the national TB control program office has adopted the following treatment guidelines, in which.the different forms of tuberculosis are categorized and their respective regimens recommended.

Category I.

Includes those new patients who have smear-positive Pulmonary TB and those who are seriously ill; smear-negative Pulmonary and Extra-pulmonary TB cases.

The treatment regimen for this category is 2 S (RHZ)/6 (EH) or 2 (ERHZ)/6EH.

Table 8. SCC regimen for new cases: 2(RHZ)/6(EH) or 2(ERHZ)/6EH

• For patients >50 years, the maximum dose of Streptomycin should not exceed 750 mg.

• During the intensive phase of DOTS, the drugs must be collected daily and must be swallowed under the direct observation of a health worker. During the continuation phase, the drugs must be collected every month and self-administered by the patient.

Table 9. SCC regimen for children of 6 years or below and seriously ill children 7-14 years old: 2S(RHZ)/4(RH) or 2(RHZ)/4(RH)

• S is to be used as the fourth drug in the intensive phase if the child is smear-positive or seriously ill.

• During the intensive phase of DOTS, the drugs must be taken under the direct observation of a health worker or the mother. During the intensive phase, the mother can collect the drugs on a weekly basis. During the continuation phase, the drugs must be collected every month and taken under the direct observation of the mother.

Category II

This category is applied to a group of TB patients:

• Who relapsed after being treated and declared free from the disease, OR

• In those patients who are previously treated for more than one month with SCC or LCC, and found to be smear positive up on return, OR

• Who still remains smear positive while under treatment, at month five and beyond.

• The treatment regimen for this category is: 2 SE (RHZ)/1E (RHZ)/5 E₃ (RH)₃.

Table 10. Re-treatment regimen: 2 SE (RHZ)/1E(RHZ)/5E₃(RH)₃²

² 5E₃(RH)₃ = 5 'months' (20 weeks) of treatment with a combination of E, R and H, three times a week on alternate days (e.g. Monday, Wednesday, Friday, etc.)

• Streptomycin should not be included in the re-treatment for pregnant women.

• Throughout the duration of re-treatment, including the continuation phase, the drugs must be taken under the direct observation of a health worker.

Category III

This refers to patients who have smear negative Pulmonary TB, Extra-pulmonary

TB and TB in Children.

The regimen consists of 8 weeks treatment with, Rifampicin, Isoniazid and Pyrazinamide during the intensive phase followed by Ethambutol and Isoniazid six months [2(RHZ)/6(EH)].

Table 11. Short course chemotherapy regimen for smear-negative PTB and EPTB: 2 (RHZ)/6(EH). For children < than 20 kg see dosage in table 5.

Long course chemotherapy (LCC):

Table 12. Long course regimen for TB: 2 S (EH)/10 (EH)

For patients > 50 years, the dose of Streptomycin should not exceed 750 mg

Streptomycin should not be given to pregnant women. These patients must be treated with EH for 12 months. Preferably all pregnant women should be treated with SCC (with Ethambutol instead of Streptomycin).

Children in this group, who are 6 years or below, only receive H in the continuation phase. Children older than 6 years may receive E and H, but have to be regularly asked if they have complaints of visual problems.

Long course chemotherapy may be preferred in case of jaundice or in patients with underlying serious liver disease.

Category IV

Treatment of chronic cases

Chronic cases can be described as those cases that continue to be smear-positive after completion of a fully supervised (initial phase and continuation phase) treatment with the -treatment regimen. These patients are considered essentially incurable with currently available regimens in Ethiopia. As these patients cannot yet be effectively cured, family members should be advised as to how to prevent transmission.

Treatment of special cases

Treatment during pregnancy and breast-feeding

Note the following:

Inquire about possibility of pregnancy before starting as well as during, TB treatment of women in the childbearing age

Preferably all pregnant women should be treated with DOTS.

Avoid Streptomycin because of the risk of toxic effects on the fetus. Replace Ethambutol in place of Streptomycin.

Breast-feeding and chemotherapy should not be discontinued.

When a breast-feeding mother has PTB, the infant should, regardless of prior vaccination with BCG, be given chemo-prophylaxis and then be vaccinated with BCG if not vaccinated before.

Treatment of patients also infected with HIV

Patients infected with HIV usually respond equally well to TB treatment as those without HIV infection, with a few exceptions:

They should always be treated with short course chemotherapy.
Use new and disposable syringe for each injection.

Initiation of ART in the course of treatment for tuberculosis should follow the WHO guidelines (see table 13).

Table 13. Antiretroviral therapy for individuals with tuberculosis co-infection

Note:

• WHO recommends that people with TB/HIV complete their TB therapy prior to beginning ARV treatment, unless there is a high risk of HIV disease progression and death during the period of TB treatment (i.e. a CD4 count < 200/mm³ or disseminated TB is present).

• If a non-nucleoside regimen is used, EFZ would be the preferred drug as its potential to aggravate the hepatotoxicity of TB treatment appears less than that of NVP. However, its dosage needs to be increased to 800mg/day.

• Except for SQV/r, protease inhibitors are not recommended during TB treatment with rifampicin due to interactions with the latter drug.

Treatment of patients with renal failure

Avoid Streptomycin and Ethambutol; give 2 RHZ/4 RH.

Treatment of patients with (previously known) liver disease (e.g. hepatitis, cirrhosis)

1. The dose of Rifampicin for these patients should not exceed 8mg per kg and for Isoniazid it should not exceed 4 mg per kg. In the case of jaundice, the treatment regimen should be changed to 2 SEH/10 EH.

2. All drugs should be taken together as a single daily dose, preferably on an empty stomach.

Treatment of patients with TB and leprosy

Patients having both TB and leprosy require appropriate anti-TB chemotherapy in addition to the standard MDT. Rifampicin will be common to both regimens and it must be given in the doses required for TB. Once the anti-TB course is completed, the patient should continue his anti-leprosy treatment.

Table 6. Symptom-based approach to management of anti TB drug side effects.

N.B

List of drugs used for the treatment of TB in Ethiopia:

• Streptomycin (S) 1 gm (vial)
• Ethambutol (E) 400 mg tablet
• Isoniazid (H) 100 mg, 300 mg tablet
• Rifampicin (R) 150 mg, 300mg tablet
• Pyrazinamide (Z) 500 mg tablet

Drugs available in fixed dose combination (FDC) are:

• Rifampicin, Isoniazid and Pyrazinamide (RHZ) 150/75/400 mg
• Ethambutol and Isoniazid (EH) 400/150 mg.
• Rifampicin and Isoniazid (RH) 150/75 mg.