download - Malaysian Thoracic Society

More documents

Recommendations

Info

Annual Congress of Malaysian Thoracic Society Symposium 5A Mycobacterium Mantoux Test and IGRA – The Myths and The Facts Pang Yong Kek Malaysia Tuberculin skin test (Mantoux test) is performed by measuring the size of skin induration after 48 - 72 hours of intradermal injection of tuberculin (previously known as purified protein derivative, PPD). It is based on the fact that TB infection induces a strong cell-mediated delayed-type hypersensitivity response to tuberculin at the injection site. Mantoux test, despite being in existence for more than 100 years, remains one of the commonest tests employed in TB diagnosis. In recent years, the newer test - the IGRA (Interferon Gamma Release Assay) stands to take over this position. There are 2 representatives in the market for this assay – the Quantiferon – Gold Test and the T-SPOT test. But, there are still misconceptions surrounding these tests. In this lecture, we will examine if some of the conceptions/beliefs are just myths - or they are supported by facts: • Mantoux test is being designed to test the presence of active TB? • The bigger the size of skin induration (Mantoux test), the likelihood of an individual developing active TB is higher? • Interpretation of Mantoux test should be the same for all individuals irrespective of their BCG vaccination status? • IGRA is more sensitive than Mantoux test in diagnosing active/latent TB? • IGRA is much helpful to differentiate active TB from latent TB, compares to Mantoux test? • When IGRA is negative, active TB can be safely excluded? • Positive IGRA is more predictive of TB reactivation than positive Mantoux test? • IGRA is useful to exclude TB in immune compromised patients or infants? • Between the 2 IGRA representatives, QuantiFERON is a better test than the T-SPOT? 39
Annual Congress of Malaysian Thoracic Society Symposium 5A Mycobacterium Non-tuberculosis Mycobacterial infection : When to treat? Aziah Ahmad Mahayiddin Malaysia There are many different species of mycobacterium other than MTB. The commonest that may cause disease in man are M. avium complex (MAC), M. fortuitum complex and M. kansasii. AIDS epidemic brought forth drastic increase of these infections. Mycobacterium infections presents with variety of clinical presentation, in the forms of pneumonia, lung disease, pleural space infections, lymphadenitis, soft tissues and skin infections, GIT infections, osteomyelitis, meningitis, disseminated and sometime IV catheter related infection. Host immunity seems to play a major role. Pulmonary disease in adults without AIDS may occur. Other populations at risk include individuals with pre-existing lung disease and other immuno-compromised conditions. The manner in which these bacteria are transmitted is not completely understood. NTM infections can occur without causing any symptoms but tuberculin skin test may be positive. The diagnosis is made from the patient’s symptoms and organisms grown in culture from the site of infection. In cases of lung infection, a diagnostic workup will include a chest x ray and tests on discharges from the respiratory passages. Diagnostic criteria of NTM Lung Disease in HIV-Seropositive and Seronegative Hosts are the presence of three positive cultures with negative AFB smear results or two positive cultures and one positive AFB smear in patients with symptoms. At least three respiratory samples should be evaluated from each patient. Other reasonable causes for the disease should be excluded. Expert consultation should be sought when diagnostic difficulties are encountered. Treatment is only initiated when diagnostic criteria are fulfilled. There have been no randomized comparative trials of treatment for disease caused by NTM , comparing one drug regimen with another or with no drug treatment at all. There have been, however, several retrospective and prospective studies of various treatment regimens on different organism. This non-typical mycobacterium are not easy to treat in any patient and the problem is complicated when the person has AIDS. Antibiotics are not particularly effective, but it is possible to contain the infection to some degree by combining different drugs e.g. For M. kansasii, a regimen of RHE for 18 mos with a minimum of 12 mo culture negativity is used. Clarithromycin will need to be substituted for rifampin in HIV-positive patients who take protease inhibitors. For treatment of M. avium pulmonary disease, a regimen of daily clarithromycin or azithromycin , rifampin, and ethambutol is recommended. Streptomycin 2-3 times per week should be considered for the first 8 wk as tolerated. Patients should be treated until culture-negative on therapy for 1 year. For M. avium disseminated disease, therapy in adults should include daily clarithromycin or azithromycin , plus ethambutol and consideration should be given to the addition of a third drug preferably rifabutin. Therapy should be continued for life until more data becomes available. Therapy of non-pulmonary disease caused by M. fortuitum, M. abscessus , and M. chelonae should include drugs such as amikacin and clarithromycin, based on in vitro susceptibility tests. Because drug therapy is not easily effective, the overwhelming infections caused by these mycobacteria in AIDS patients can be fatal. 40
Page 2 and 3: anniversary MALAYSIAN THORACIC SOCI
Page 4 and 5: AnnuAl Congress of MAlAysiAysi An T
Page 8 and 9: anniversary MALAYSIAN THORACIC SOCI
Page 18 and 19: Annual Congress of Malaysian Thorac
Page 90 and 91:
Annual Congress of Malaysian Thorac
Page 92 and 93:
Annual Congress of Malaysian Thorac
show all

download - Malaysian Thoracic Society

Create successful ePaper yourself

Delete template?

Save as template?