Does polymerase chain reaction test confirm tuberculosis?
Associate Consultant,
Department of Microbiology,
Tata Medical Center, Kolkata
Q: I am a 29 years old female who is trying to conceive another child for the last one year. I have a three years old daughter also. After the months of follicular study, my doctor recommended hysterosalpingogram (HSG) following which I was advised TB-PCR using endometrium tissue as sample. The polymerase chain reaction (PCR) test came out positive and Mycobaterium found present. Now the doctor has asked me to start six months of AKT 4 treatment followed by AKT 3. What are the side effects of the AKT 4 treatment? Can I conceive after the completion of six months therapy?
A:PCR or polymerase chain reaction, is an amplification based molecular test, which under ideal laboratory conditions is a highly sensitive and specific method for the detection of target genes including those of Mycobacterium tuberculosis (the bacteria causing tuberculosis). The reliability of the PCR is dependent on technical factors, and in good quality assured laboratories, a positive PCR test in the appropriate clinical context has a high positive predictive value for the diagnosis of tuberculosis. However, because of its extreme sensitivity PCRs in general are susceptible to amplicon contamination a phenomenon which can give rise to false positive results (this phenomenon is not uncommon and is sometimes but not always detectable and preventable throughgood laboratory practices and suitable PCR controls).
The diagnosis of TB of the reproductive system (e.g. endometrial TB) is dependent on several factors which include clinical history, epidemiological context, physical examination findings, results of investigations (which may include HSG or hysterosalpingography) and laboratory results (microscopy, culture for M. tuberculosis, and histopathology). For definitive diagnosis Mycobactrium culture and histopathology/cytology report from endometrial biopsy/aspirate is required. No single diagnostic parameter can be relied upon, and often it is the combination of findings (both clinical and laboratory) which helps the physician to reach a provisional or definitive diagnosis. The risk from endometrial tuberculosis could be classified into local effects (e.g. subfertility) and systemic effects (e.g. dissemination of untreated or partially or inadequately treated TB to other parts of the body). It is difficult to say from the details provided if this diagnosis has been made early enough.
The side effects of AKT4 therapy (drugs used to treat TB such as Rifampicin, Isoniazid, Pyrazinamide, Ethambutol) include development of liver function abnormalities (including hepatitis due to Rifampicin, Isoniazid, Pyrazinamide), peripheral neuropathy (due to Isoniazid which is preventable through vitamin B6 or pyridoxine therapy), hyperuricemia (causing gout due to Pyrazinamide), ocular disturbances (optic neuritis causing vision disturbances e.g. due to Ethambutol). Hence all patients taking therapy against TB should be under regular health care supervision and monitoring. It is possible to conceive following successful therapy for endometrial TB. However, because of the inflammatory reaction induced by the TB bacilli- uterine synechia or adhesion of the walls of the endometrium and affection of fallopian tubes difficulty in conception and even infertility is a possibility.