DIAGNOSIS & MANAGMENT OF TB
DR. MOSHTAK WTWT
Diagnosis:
A- TESTS: *CXR *general: CBP, ESR, CRP, ETC…. *TST *stain (Ziehl-Neelsen & auramine fluorescence). *PCR *culture, solid(Lowenstein-Jensen, middle brook) & liquid(BACTEC). *Empirical Anti TB(usually seen after 5-10 days).
B- Specimen: *respirotery: sputum, gastric washing, bronchoalveolar lavage, transbronchial biopsy. *non-respirotery: fliud examination(CSF, ascitis, pleural, pericardial, joint). Tissue biopsy(pleural, pericardial, bone marrow, liver). *5000-10000 acid-fast bacilli stain become +ve. *only 10-100 viable organisms for sputum culture +ve. *if MDRTB is suspected, molecular tool may be used to test presence of the rpo gene 95%.
() Tuberculin Skin Test (TST): 1- Heaf test(tine test): multiple puncture technique, which reads at 3-7 days as: Grade 1: 4-6 discrete papules. Grade 2: confluent papules forming ring. Grade 3: central induration. Grade 4: > 10 mm induration. 2- Mantoux test: 10 tuberculin units of purified protein in 0.1 ml normal saline intradermally in flexor aspect of the forearm, read at 2-4 days as: +ve when induration 5-14 mm (G2 Heaf), > 15 mm (G3-4 Heaf).
The false –ve tests occur in : *sever TB. *newborn & elderly. *HIV *recent infection(measles) & immunization. *malnutrition *immunosuppression. *malignancy *sarcoidosis. The false +ve tests occur in: *BCG *areas where exposure is high. These limitations may be overcome by the development of whole gamma-interferon assays as earely secretoty antigenic target(ESAT-6)
CONTROL & PREVENSION: BCG is a live attenuted vaccine derived from M bovis used for: *stimulate protective immunity *Ca bladder it indicated in: 1-contact < 2 years old. 2- immigrant from countries where TB is endemic. 3- infants in high-prevelance ethenic groups. 4- health-care workers at high risk It is not effective at preventing “secondary” TB or reactivation of TB from the latent state.
Occasional complications: bladder infection, dysurea, polyurea, hematurea, prostatitis, flu-like illness, local skin BCG abscess, dissemination infection, shock in immunocompomised. BCG contraindicated in: 1- HIV +ve. 2- burn. 3- TST +ve.
Chemoprophylaxis: refampicin & INH for 3 months or INH alone for 6 months. Indicated in: 1- documented new TST over past 2 years. 2- tuberculin- positive contacts of patients with active TB. 3- tuberculin-negative contacts of patients with active TB. 4- tuberculin-positive persons with HIV. 5- +ve TST of unknown duration in patients younger than 35 years. 6- CXR with inactive TB. 7- TST +ve with DM, gastrectomy, silicosis, CS, alcoholism.
() Chemotherapy: A-regimes: *initial phase(rapidly reduce bacterial population). *continuation phase(destroy any remaining bacteria). *6 month therapy : for *all patients with new-onset *uncomplicated pul or extra-pulm TB. *9-12 months: for *HIV +ve. *drug intolerance. *meningitis. *after 2 weeks of starting Anti TB, the patient become non-infectious. *()smear –ve pul TB AS: initial phase---2M H3,R3,Z3,E3 continuation-----4M H3,R3. *() in relapse or Rx failure: initial phase---2M H3,R3,E3,S3 continuation---5M H3,R3,E3. *()in extrapulmonary TB: initial phase---2M H3,R3,Z3,E3 OR S3 continuation---4M H3,R3
()Drugs: 1st line: rifampicin, isonizide, pyrzinmide, ethambutol, streptomycin. 2nd: Na-p-aminosalicylate, ethionamide, prothionmide, capreomycin, cycloserine, ciprofloxacin, clarithromycin, amikacin, kanamycin. *when start Rx should do: 1-base line LFT. 2- RFT. 3- optic disc examination. 4- HIV test. *CS indicated in : 1- miliary TB 2- Meningeal 3- TB pericarditis 4- TB pleural effusion 5- TB of ureter 6- children with endobronchial disease 7- HIV 8- sever pul TB. 9- drug hypersensetivity. ()surgery: massive hemoptysis, loculated empyma, constrictive pericarditis, LN suppuration, spinal cord disease.
()DOTS: (1995) Directly observed therapy , in which : *supervised therapy. *2 to 3 times per week. *improve adherance & control of TB. *currently recommended for : homless, alcohol , drug users, mentally ill pateints, history of non-compliance.
() Complications: A-pulmonary: *massive hemoptysis *cor pulmonale *fibrosis/emphysema *aspergilloma *lung/pleural calcification. *bronchiectasis *bronchopleural fistula. B- Non-pulmonary: *empyema necessitans *laryngitis *enteritis *anorectal disease *amyliodosis *poncet’s arthropathy