Tuberculosis (Diagnosis)

Diagnosis:

• Proper patient history: it is most essential to know the duration, elicit history of rise of temperature in the evening, ask about amount of blood in cough or sputum and to look out for alert signs.

• Physical examination – auscultation of the chest being an important one.

• Sputum smear – it is collected to carry out Acid Fast bacillus smear and culture. The sputum should be collected for 3 consecutive days preferably in the early morning (the gastric aspirate may give a better specimen)and in hospitalized patient is collected every 8 hourly.

• Skin test – 0.1 ml of purified protein derivative (PPD) is injected in your skin and the results are read after 3 days. After 48-72 hours the doctor sees how one reacts to the test. Whether there is an induration on the skin (>5mm). One is expected not to clean the area of injection with water or soap.

• Nucleic Acid Amplification test– Deoxyribonucleic acid (DNA) is specific for mycobacterial ribosomal RNA identification, it is done by taking sputum and testing it within 2 hours of collection by mixing with preloaded vial of NAA.

• Interferon-Gamma Release Assays (IGRAs)- The white blood cells of an infected person release interferon gamma when mixed with antigens which is derived from mycobacterium tuberculosis.

• Radiograph of the chest- Chest X-ray shows us changes in lung parenchyma like white area with few enlarged lymph nodes near the heart shadow, we can see associated complications ~ pleural effusion, pneumothorax, or collapse.

• CT Chest- is carried out to study more minute changes in the lung parenchyma like cavity in lung, white area representing consolidation, small tuberculoma with calcifications and mediastinal lymph nodes.

• Lung biopsy – In uncertain cases and when in doubt lung biopsy could give confirmative results.