tailieunhanh - INFECTIOUS DISEASES - PART 10

Giải thích kết quả từ TST Người nhận trước của vắc xin BCG. Nói chung, giải thích kết quả TST trong BCG người nhận là giống như đối với những người đã không nhận được thuốc chủng ngừa BCG. Sau khi tiêm chủng BCG, phân biệt giữa một kết quả TST tích cực gây ra bởi M bị nhiễm trùng lao | Interpretation of TST Results in Previous Recipients of BCG Vaccine. Generally interpretation of TST results in BCG recipients is the same as for people who have not received BCG vaccine. After BCG immunization distinguishing between a positive TST result caused by M tuberculosis or M bovis infection and that caused by BCG can be difficult. Reactivity of the TST after receipt of BCG vaccine does not occur in some patients. The size of the TST reaction ie mm of induration attributable to BCG immunization depends on many factors including age at BCG immunization quality and strain of BCG vaccine used number of doses of BCG received nutritional and immunologic status of the vaccine recipient and frequency of TST administration. Tuberculosis disease should be suspected strongly in any symptomatic person with a positive TST result regardless of history of BCG immunization. When evaluating an asymptomatic child who has a positive TST result and who possibly received BCG the result should not be attributed to BCG vaccine. Certain factors such as documented receipt of multiple BCG immunizations as evidenced by multiple BCG scars decrease the likelihood that the positive TST result is attributable to LTBI. Evidence that increases the probability that a positive TST result is attributable to LTBI includes known contact with a person with contagious tuberculosis a family history of tuberculosis disease immigration from a country with a high prevalence of tuberculosis a long interval Ũ5 years since neonatal BCG immunization and a TST reaction Ũ15 mm. Prompt clinical and radiographic evaluation of all children with a positive TST reaction is recommended. In most circumstances a history of BCG will not account for the positive result. Chest radiographic findings of a granuloma calcification or adenopathy can be caused by M tuberculosis but not by BCG immunization. For the child with signs and symptoms consistent with abdominal tuberculosis and a history of ingestion of .