Gupta AS
Tuberculosis is a public health issue in India which is a high incidence country. Extrapulmonary tuberculosis besides involving the reproductive organs can also involve the gastro intestinal tract, meninges, brain, skin, bones, joints and almost any organ in the body.
Genital Tuberculosis is rampant in India. Estimated prevalance is about 20% though this may still be the tip of the iceberg as it is usually asymptomatic; diagnosis is difficult and many of the diagnosed cases may not be reported. It silently damages the reproductive potential of the woman. Most of the times it is incidentally detected during an infertility work up in a young woman. Gynecologists may be the first consultants to see these women.
Unlike pulmonary tuberculosis all extrapulmonary tuberculosis including genital Kochs are paucibacillary. Very few mycobacterium tuberculosis complex can be isolated from these sites making the diagnosis and identifying the causative organism more difficult. Besides being paucibacillary obtaining specimens for diagnosis usually requires invasive or operative procedures.
Gynecologists when they encounter or suspect genital tuberculosis should be well informed about the latest diagnostic modalities that should be used to clinch the diagnosis. They should also be aware of all the samples that need to be collected, proper method of transport to the laboratories, designated laboratories performing the tests and storage of the samples in case of delay in reaching the laboratory.
Multiple diagnostic modalities can be used for diagnosis of genital Kochs. Microbiological tests would include smear and staining for acid fast bacilli, culture for mycobacterium tuberculosis; MGIT (Mycobacterium Growth Inference Tube). Molecular tests detect the nucleic acid of the organism. This would include the cartridge based nucleic acid amplification (CBNAAT), Gene Xpert, TB PCR, linear assays. These tests will also detect the drug resistance to first line drugs mainly rifampicin and isoniazid. Specimens that should be collected by the gynecologist when they suspect genital Kochs includes fluids and aspirates from the endometrial cavity, peritoneal cavity or washings, secretions from the vagina and the cervix. Quantity of the fluids should be as large as possible (5-10 ml) as the infection is paucibacillary. These fluids are sent in the Gene Xpert tubes that identifies the DNA of the organism and gives the report within a couple of hours. These fluids are also sent for culture (MGIT). Tissue biopsies that are sent for culture should be sent in sterile normal saline and not in formalin. During transport to the laboratory they should remain moist and temperature should be at 4 -15°Celsius. If specimens cannot be transported to the laboratory within one hour, it is recommended to store them at 4°C. Tissue biopsies, endometrium for CBNAAT have to be prepared in the laboratory to free the organism from the cellular debris. Contaminated specimens require rigorous decontamination procedures to eliminate the unwanted normal flora to prevent their overgrowth and consumption of the entire media before the TB bacilli even start to grow.
All concerted efforts should be made to clinch the diagnosis. However, if the specimen sent does not have the bacilli ( paucibacillary nature) the tests will be false negative. Hence the 2016 revised national tuberculosis control program (RNTCP ) guidelines permits the treatment of tuberculosis on clinical suspicion even if bacteriological or histopathological diagnosis cannot be established.
The May issue is ready for our esteemed readers and we hope that it is as informative as our previous issues.