Diagnosis Of Tuberculosis

TUBERCULOSIS DIAGNOSIS

How To Diagnose TB?? • Tuberculosis is diagnosed by finding Mycobacterium tuberculosis bacteria in a clinical specimen taken from the patient. • A complete medical evaluation from tuberculosis (TB) must include: – – – – –

Medical history Physical examination Tuberculin skin test Chest X-ray Microbiological examination

Medical History • Includes obtaining the symptoms of:

•Fever

•Nighttime sweating •Loss of appetite

•Loss of weight •Constant tiredness

•Persistent cough

• It is also important to consider demographic factors (country of origin, age, ethnic @ racial group, occupation) that may increase the patient risk of exposure to TB or to drug resistant TB. • Should determine whether the patient has medical conditions esp. HIV infection that increase the risk of latent TB infection progressing to TB disease.

Physical Examination • Is done to assess the patient’s general health and find other factors which may affect the TB treatment plan. • It cannot be used to confirm @ rule out TB

Tuberculin Skin Test • Usually known as the Mantoux tuberculin skin test. • Is a method for screening for exposure to TB infection. • A person who has infected with TB will have developed a hypersensitivity to the TB bacteria even they did not develop the disease. • Is performed by injecting a small amount of fluid (tuberculin) into skin in the lower part of the arm. • The skin area is inspected 48-72 hours later for a bump.

• The reaction is read by measuring the diameter of induration across the fore arm in millimeter (mm). • A positive response usually shown by a hard, raised bump at the injection site – likely to have TB infection. • Skin test are not 100% accurate and they did not always indicate the presence of active disease.

Chest X-ray • A chest radiograph is used to detect chest abnormalities. • Lesion may appear anywhere in the lungs and may differ in size, shape, density and cavitation. • Abnormalities may suggest TB, but cannot be used to definitively diagnose TB.

• Chest radiograph may be used to rule out the possibility of pulmonary TB in a person who has had a positive reaction to Mantoux test and no symptoms of Abnormal chest X-ray. Arrow points to disease. cavity in patient’s right upper lobe.

Microbiological Examination • The acid fast smear plays an important role in the early diagnosis of mycobacterial infections. • Microscopy is the oldest, easiest, most rapid and inexpensive procedure that can be performed in the laboratory to detect the present of acid-fast-bacilli (AFB). • Detection of significant number of AFB (using Ziehl-Neelsen stain) in sputum @ tissue sample is considered a positive diagnose, although disease may confirmed by laboratory culture of the bacterium (difficult & slow-takes at least 4 weeks).

• If bacteria that cause TB infection grow in the culture (OGAWA & LJ media), other test may be done to determine which antibiotic will be most effective in treating the infection – sensitivity testing. • A positive culture for M. tuberculosis confirms the diagnosis of TB disease.

Acid Fast Staining Using ZiehlNeelsen Method Enjoy your watching!!!~