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Prisoner Health Update: Tuberculosis

by Eike Blohm, MD

Tuberculosis (TB) is an illness caused by a mycobacterium, a class of bacteria that is hard to see under the microscope, difficult to grow in culture, and has the audacity to live in the very immune cells (marcophages) that are tasked with hunting and killing bacteria. TB affects only humans, and traces of the disease can be identified by archeologists in the oldest mummified human remains.

How is TB transmitted?

The bacterium travels in the microscopicdroplets that get expelled when an infected person coughs. These droplets can be so small that they travel right through the holes in cloth masks, and only N95 masks offer protection. Fortunately, inhalation of a single droplet does not suffice to transmit the infection. Exposure in close quarters – such as prison – is usually needed to facilitate the spread of TB.

What happens when a person gets exposed?

There are three possible outcomes after exposure. The body’s immune system may kill all TB bacteria, and the infection is cleared. Or the TB bacteria may overpower the body’s defenses, and the person develops ACTIVE tuberculosis. It’s also possible that a stalemate ensues – a situation known as LATENT tuberculosis. A person with latent TB often has few symptoms but continues to carry the bacteria in their lungs. At any time, latent TB can revert to active TB and the person then develops symptoms and can infect others.

What are symptoms of active TB infections?

Tuberculosis used to be called “consumption” because it slowly kills the host. In the 18th century, artists purposefully sought to get infected because they believed the slow dying process would enhance their artistic ability (turns out it didn’t). Chronic cough, often with blood-streaked sputum, low-grade fevers, night sweats, and weight loss are the hallmarks of infection. However, TB can escape the lungs and cause disease in other parts of the body. It has a proclivity to infect the bones of the spine, cause bleeding in the adrenal glands, or cause an effusion around the heart.

How do doctors test for TB?

All prisoners should get a PPD test once a year. A protein from the TB bacterium is injected under the skin, and if the immune system has previously seen it, a pronounced reaction occurs within 48-72 hours, in which the area becomes red and indurated (rubbery). This does not mean a person has tuberculosis, only that they have been previously exposed (or vaccinated, although TB vaccination is not routine in the US). A blood test, called interferon-gold, is also available but more expensive.

A positive PPD test requires that a patient then gets a chest x-ray. The radiograph looks for scarring, hilar lymphadenopathy (swollen lymph nodes around the heart), granulomata (calcified areas of infection), or a radiographic sign called a “Gohn complex.” Any of those indicate the possibility of latent or active tuberculosis. Analysis of the person’s sputum under the microscope with an acid-fast stain establishes active TB if the bacteria can be seen.

How is TB treated?

Latent TB infection is treated with isoniazid. This medication can interfere with the production of a neurotransmitter called gamma-aminobutyric acid (GABA), but this is typically only a problem in overdosed or malnourished individuals. Yet without GABA, a person will have intractable seizures. As prison diets are seldom healthy, a person on isoniazid should discuss with their prescriber supplementation with vitamin B6 (pyridoxine), a precursor to GABA that mitigates the toxicity of isoniazid.

Active TB requires a negative pressure room to prevent the spread of infection to others. In addition, patients need to take a drug-cocktail based on local resistance patterns. Over the last decade, a strain of drug-resistant tuberculosis has emerged, but fortunately it is still rare in the United States.

Disclaimer: This column aims to educate prisoners about common health concerns but does not constitute medical advice. It is no substitute for evaluation by a trained medical professional.