Tuberculosis

Dr. Parang Mehta, MD.

Tuberculosis is one of the most dreadful diseases that afflict mankind.  In adults, it is usually restricted to the lungs, but it is much more dangerous in children.  Because of their poor immunity, this disease can spread all over the body and affect various organs.  Tuberculosis of the brain and its coverings (CNS tuberculosis), and a disseminated form called miliary tuberculosis, are especially dangerous, with high death rates.

Children are unable to restrict Tuberculosis to one organ. The disease spreads to the brain and other organs

Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis.  It usually enters the body of the child through the lungs and localizes there.  The source of infection is usually an adult with active tuberculosis of the lungs and cough.  The initial focus of infection in the lungs usually spreads only to the nearby lymph nodes, and then becomes quiescent.  Before this however, the bacteria may have spread through the bloodstream to various organs and settled there.

The initial infection in the lungs, and the involved lymph nodes and vessels, are together called a Primary complex.  While not very dangerous in itself, it is a pointer to the presence of tuberculosis infection in the body, which may grow and spread at some time in the future, when conditions are favourable for the bacteria.  For example, whooping cough, measles, malnutrition, AIDS, and other disorders weaken the body's defense systems, and quiescent tuberculosis bacteria often take advantage to grow rapidly and cause serious disease.

This is the reason even a primary complex is treated with a full course of antitubercular drugs. The aim here is to eradicate the bacteria completely, making the child safe for the future.  Other forms of tuberculosis, like pneumonia and lymphadenopathy are also common manifestations in children, and require appropriate treatment by an expert.

Tuberculosis has returned to countries like the USA where it had ceased to be a major problem, because of the current epidemic of AIDS.  A serious concern today is the increasing incidence of drug resistance in Mycobacterium tuberculosis, which makes treatment difficult, prolonged, and much more expensive. Two terms in use:

MDR Tuberculosis:  Multi Drug Resistant Tuberculosis. The bacteria are unaffected by some first line drugs.

XDR Tuberculosis:  Extensively Drug Resistant Tuberculosis. The bacteria are resistant to several drugs, including second line injectable drugs.

BCG Facts

Though BCG can't prevent infection with tuberculosis, it prevents dangerous forms of the disease

BCG is the vaccine in use around the world for protecting against tuberculosis.  It is given as a single dose intradermally (into the skin), soon after birth.  It is a live bacterial vaccine, made by gradual weakening of the bacteria.   Like other live vaccines, this vaccine sets up a small infection in the body. It is enough to generate immunity, but does not usually cause disease.

From time to time, controversies are repeated about the BCG vaccine.  The facts are thus:

 

Last Revision: May 22, 2020