Pulmonary Tuberculosis

Pulmonary tuberculosis is infection of the lung parenchyma by Mycobacterium tuberculosis, spread by airborne droplets from people with cavitary or smear positive disease. It remains a leading infectious killer in Kenya, strongly linked to HIV, malnutrition, diabetes, smoking, alcohol and crowding.

• Primary infection may progress directly or reactivate years later.
• Drug resistance (rifampicin resistant and multidrug resistant) must always be excluded.

Cough over 2 weeks, haemoptysis, fever, night sweats, weight loss, anorexia, chest pain, dyspnoea.

• Examination: wasting, crackles, bronchial breathing, pleural rub, finger clubbing; HIV associated disease may show atypical, lower zone or miliary patterns with negative sputum.
• Differential diagnosis: bacterial pneumonia, lung abscess, lung cancer, pulmonary mycoses, pneumocystis pneumonia, sarcoidosis, bronchiectasis, non tuberculous mycobacteria, melioidosis, pulmonary embolism, COPD exacerbation.
• Complications: massive haemoptysis, pneumothorax, pleural effusion and empyema, bronchiectasis, cor pulmonale, aspergilloma, respiratory failure, dissemination (miliary, meningeal), drug resistance, post tuberculosis lung disease, death.

Bacteriological confirmation is preferred.

• Sputum for Xpert MTB/RIF Ultra (detects tuberculosis and rifampicin resistance), smear microscopy and mycobacterial culture with drug susceptibility testing; two samples including an early morning sample.
• Chest radiograph (upper zone infiltrates, cavities, fibrosis, lymphadenopathy); urine lipoarabinomannan test in HIV positive patients with CD4 under 200 or seriously ill.
• HIV test, CD4, glucose, full blood count, liver and kidney function, hepatitis B and C serology before treatment.

Start treatment when diagnosed and ensure completion.

• Supportive: nutritional support, directly observed therapy or digital adherence, infection control (cough etiquette, ventilation, respirators for staff), contact tracing, stop smoking and alcohol, screen for diabetes and HIV, treatment supporter.
• Pharmacological: 2 months of isoniazid, rifampicin, pyrazinamide and ethambutol followed by 4 months of isoniazid and rifampicin. Adult doses per kg daily: isoniazid 5 mg (maximum 300 mg), rifampicin 10 mg (maximum 600 mg), pyrazinamide 25 mg, ethambutol 15 mg. Fixed dose combination (isoniazid 75 mg, rifampicin 150 mg, pyrazinamide 400 mg, ethambutol 275 mg): 30 to 37 kg 2 tablets, 38 to 54 kg 3, 55 to 70 kg 4, 71 kg and over 5 tablets daily. Children daily: isoniazid 10 mg/kg (7 to 15), rifampicin 15 mg/kg (10 to 20), pyrazinamide 35 mg/kg (30 to 40), ethambutol 20 mg/kg (15 to 25). Pyridoxine 25 to 50 mg daily. Four month alternative for people aged 12 years and over: 8 weeks of rifapentine 1200 mg, isoniazid 300 mg, pyrazinamide and moxifloxacin 400 mg daily, then 9 weeks of rifapentine, isoniazid and moxifloxacin. HIV coinfection: start antiretroviral therapy within 2 weeks if CD4 under 50, otherwise within 8 weeks; dolutegravir 50 mg twice daily while on rifampicin and for 2 weeks after; cotrimoxazole 960 mg daily. Rifampicin resistant or multidrug resistant: a 6 month oral regimen of bedaquiline, pretomanid, linezolid and moxifloxacin, under specialist care.
• Procedures: therapeutic aspiration or chest drain for effusion or empyema; embolisation or surgery for life threatening haemoptysis; surgery for destroyed lung or aspergilloma.
• Special groups: pregnancy, give isoniazid, rifampicin, pyrazinamide and ethambutol with pyridoxine and avoid streptomycin; liver disease, use isoniazid, rifampicin and ethambutol modified or streptomycin based regimens under specialist care; renal impairment, give pyrazinamide and ethambutol three times weekly; children, weight band dosing; diabetes, insulin and glycaemic control.
• Red flags: massive haemoptysis, respiratory failure, jaundice or ALT over 3 times upper limit with symptoms (stop and reintroduce stepwise), visual changes on ethambutol, positive smear at 2 months, rifampicin resistance.
• Follow-up: weight and symptoms monthly; sputum smear or culture at end of month 2 and at month 5 and 6; liver tests if symptomatic; document outcome; post treatment review at 6 and 12 months.