World Tuberculosis Day: Evolution of TB Diagnosis in India
Tuberculosis (TB) was once feared as much as, AIDS is feared today. This social perception comes from the fact that it is a highly communicable disease and can become difficult to treat. Since it was perceived to be caused purely due to lifestyle habits like smoking, eating tobacco, et cetera, it was invariably seen as a punishment for sin.The fact of the matter is and always was that Tuberculosis is a contagious air-borne disease that usually affects the lungs. TB is caused by the Mycobacterium tuberculosis bacteria, which is transported through breathing in contaminated air.
Today, India accounts for the highest number of TB cases in the world, as per the World Health Organization (WHO). The 2016 TB statistics give an estimated incidence figure of 2.79 million cases in India alone.
But Tuberculosis is curable.
The change in medical science over decades has led to a massive increase in the rate of survival for patients afflicted with TB. The biggest impact has been in part, due to the most important step: An Early Diagnosis.
Diagnosis of Tuberculosis is performed through a process called the ‘culture method’, typically through solid culture media, which allows the organism to grow by giving them nutrition (the L J Media). This medium allowed the TB microorganism to proliferate, after which further tests had to be undertaken, to confirm the type of Mycobacterium.
This tedious and highly time-consuming process was necessary, because not all bacteria cause tuberculosis.
Even in late 20th Century, nearly 60 years after discovery of L J Culture, when a person was suspected of having TB, his sputum would be collected early in the morning, and taken to be plated on the L J Media, allowing TB microorganism to grow, followed by further tests to confirm the presence and type of TB bacteria.
The challenge here was, only the collection and proliferation process would take up to 5 weeks, let alone detecting a single presence of TB bacteria or gauging the type of bacteria, to map out treatment procedures. Another major challenge was that, many a time, due to transportation and infrastructure hurdles, the sputum would never make it to the labs for it to be tested. This unfortunately led to a lot of patients being left untreated.
Contributing negatively to the scenario was not just the time delay, ironically, it was also medication. With time, TB bacteria became resistant to major drugs, which made it more challenging to treat, even if detected. Professionals would have to run continuous tests to figure out permutation and combinations of medication that would work on patients, which led to increased risk of higher resistance.
In this fight between the time taken to detect, and the time taken to treat, the patient inevitably suffered and most often succumbed to the disease. This mix collectively aggravated the scale of the hurdle, to adequately and timely treat TB afflicted patients.
Medical Advancements And Diagnosis
Forward to 2018, medical advancements, technology, and determination to take down TB by the year 2025 have all led to better diagnostics and treatment methods. The same process which took weeks for completion, today takes less than a day.
Today, through molecular detection (nucleic acid amplification-based methods) presence of TB bacteria is confirmed on the day of sputum collection itself, as opposed to 5 weeks. This is of course is with the help of new technology, through a machine called Genexpert, and similar such machines.
Alongside molecular detection, is of course, the age old ‘culture method’. Culture is still considered the gold standard and is performed even today, to detect the presence of TB bacteria. There has been a development in this space, as well. A newer method of culture called ‘Liquid Culture’ has gained popularity in pathology.
Briefly put, liquid culture allows large amounts of microorganism to grow within 3 weeks, as opposed to 4-6 weeks of solid culture, followed by running further tests to confirm the type of bacteria. Through liquid culture, the bacteria growth can be directly loaded onto a new advanced machine called ‘Malditof’ using the mass spectrometry technique. This machine can identify any bacteria in less than 5 minutes.
The Contribution Of Machines In Diagnosis
Instruments such as the GenXpert, not only alert you of the presence or absence of TB, but also indicate whether the particular bacteria are resistant to important antibiotics like Rifampicin, thereby making the disease multi-drug resistant. Treatment protocol in cases of multi-drug resistant TB is completely different. These tools and tests help in taking accurate measures towards appropriate treatment. All in all, a patient can be accurately diagnosed and treatment can commence, on the same day.
In a country with the highest burden of Tuberculosis, it should be a matter of utmost urgency that we tackle it from all possible angles. Treatment and cure is only one part of the war against TB. Time is one of the biggest contributors to disease-related mortality. With speed on our side, it is possible to take on and defeat even such a highly contagious ailment. The question we must continuously ask ourselves is: Are we doing enough?
Dr Ajay Phadke is the Centre Head of SRL Dr Avinash Phadke Path Labs, Mumbai. He is also a Health Council Member at Healthhunt.