Tuberculosis in Guyana

Though my main task at the Georgetown Chest Clinic has been increasing the usage of the GHIS and helping the staff to incorporate the system into their daily routine, I had to first learn how the clinic works to learn how to make the system work for them - and to help the doctors learn the system, I inadvertently learned how to treat tuberculosis (TB)!

When people come to the clinic, they have usually been referred by their doctor or MOPD (Medical Outpatient Department) - or they are a TB contact or just want to be tested. For those who are a contact or want to be tested, the first step is a Mantoux test (aka skin test, tuberculin test or PDD test - purified protein derivative). The tuberculin is inserted into the top layers of the skin, usually on the arm. The site reacts immediately to the volume of liquid injected by creating a bump, but if done correctly, this is absorbed quickly. The site should be read 48-72 hours after the injection and the health care worker is looking at the amount of swelling (creates a palpable, raised, hardened area), not redness or bruising. The test is read in millimeters and a standard positive reading is greater than 15mm, but this varies depending on whether the health status or exposure of an individual. Individuals with kidney disease, diabetes or working in the health field, are considered positive at 10mm and an individual who is immuno-compromised (i.e., HIV positive) is considered to have a positive TB test at 5mm.

A positive test means that an individual has been exposed to the TB bacteria in the past and has a TB infection. It is possible to have a TB infection, but not to have TB disease. The concern is that if you have TB infection, you could develop TB disease. My understanding is that we don't treat infection in Canada unless immuno-suppressed or in a specific work setting (health care, schools), but it is standard here to prescribe anyone infected prophylaxis treatment of isoniazid and B6 to prevent the disease and the vitamin to prevent side effects of the treatment.

If you are testing positive for TB infection and have the symptoms (cough for more than two weeks, night sweats, fever, weight loss, loss of appetite) then the next step is to get a chest x-ray done (anterior-posterior) and do a sputum test. The sputum test involves coughing up sputum (or "cold" in Guyana, aka the thick stuff in your lungs that you can bring up when you breathe deeply, especially when sick) into a cup which we send to the lab. The lab does a AFB sputum microscopy test which tests for the number of tuberculosis bacterium in the sample. A negative sample means there are no bacteria (or not enough to be detected by regular microscopy - at which point doctor may ask for sputum culture which will grow bacteria if there are any there) or a sample can be positive (1+, 2+, 3+, 4+) which reflects the number of bacteria in the sample.

A normal chest x-ray shows black air space in the shape of lungs with light rib markings. Lung disease is characterized by opacities. I am not sure how different pneumonia looks from tuberculosis, but if pneumonia is suspected (not TB), then they will be prescribed antibiotics that would treat pneumonia - doesn't work, treat for TB! Often chest x-rays will show cloudiness in specific lobes of the lung or blurred angles of the lung. If there is fluid, then you can often see a line to see how high it is. Another type of TB is miliary tuberculosis (most common is pulmonary TB). I think miliary TB can occur anywhere in the body, but it is characterized on chest x-rays by a "millet" pattern that looks like millet seeds.

If tuberculosis is suspected somewhere else on the body (can occur in any organ, bone, lymph nodes etc) then the only conclusive test is a biopsy, but quite often it is diagnosis by treatment. The cases I have seen are noticeable masses protruding from the spine or neck. Treat for tuberculosis and if the mass shrinks, correct diagnosis! Once a diagnosis of TB has been made, there is a standard treatment of four drugs (isoniazid, rifampicin, pyrazinamide and ethambutol) every day for 2-3 months then only the first two drugs every other day for 4-6 months. A supplement of B6 is also taken. Obviously more education and other criteria required, but that's the basics.

The DOTS program is the WHO standard for curing TB. It stands for Directly Observed Treatment Short-course. The number one reason for not completing treatment is that patients start to feel better two months after taking the drug, but the bactera is very tough and needs the combination and long term treatment to kill all of them. With the DOTS program (theoretically), a health care worker visits you every day and gives you your treatment to take. A DOTS worker should be aware of their patient's attitude and how they are feeling. The DOTS program is supposed to have a 90% cure rate, but I think it is only 60% in Guyana. Not all workers take their job seriously and not all patients understand the seriousness of not treating the disease. If someone misses one month of treatment, they are called a re-treatment case, but if they miss more than two months, then they are considered a defaulter. The program has been increasing their activity to catch these defaulters.

There has been a rise in multi-drug resistant TB in Guyana which is very scary. It is related to defaulting on treatment, multiple treatment restarts and allowing bacteria to build a resistant to the standard TB treatment drugs. There are second-line drugs and even third-line drugs that can be used, but it is not a desirable situation to have multiple MDR cases with active TB (spreading the disease).

If all goes well, TB is curable! I wish everyone at the clinics and the National TB Program the best of luck as they continue to monitor and treat this disease. It has its challenges, but if they are all committed and work together, I know they will do great things for TB in this country - as in get rid of it!!