Introduction

Tuberculosis, or TB, is the disease caused by Mycobacterium tuberculosis. It has afflicted man throughout the ages - signs of TB have been found in mummies for example. In Victorian England it was a dreaded disease striking down young people in their prime - it was known as the "consumption" for the way the disease caused rapid weight loss. The disease was endemic due to overcrowding and poor nutrition. Although TB is not so common in the UK now, it is a major health issue worldwide especially in sub-Saharan Africa (often in conjunction with HIV). Most cases diagnosed in the UK are imported. The TB germ is slow-growing and this means it requires a long course of multiple (3 or 4) antibiotics for cure - at least 6 and up to 24 months. Multi-Drug Resistant TB (MDR TB) requires treatment with second-line drugs¹ for longer. These antibiotics all have significant side-effects eg eye and liver problems. In the USA treatment regimes have been enforced with confinement to reduce the rate of MDR TB. In the UK hospital treatment for infectious ("open") TB can be compelled; patients leaving hospital can be arrested.

Tuberculosis is usually contracted by inhaling tubercle bacilli coughed out by an open case, so overcrowded living conditions increase the likelihood of transmission. This causes primary TB where there is a spot visible on chest Xray often (called the Ghon focus). Usually the body fights this off. The tubercle bacilli lay lurking though, and can reactivate during severe illness, immune deficiency states (eg during chemotherapy, steroid treatment and HIV infection) or just old age. TB can affect all the organs of the body - the small intestine simulating Crohn's disease, kidneys, skin (lupus vulgaris), bones (this is what the Hunchback of Notre Dame had), joints, meninges (TB meningitis was a scourge of children) - the list goes on and on. Because TB can affect so many organs, the symptoms of TB are equally as varied. Pulmonary TB, the most common form, typically presents as a chronic cough not responding to ordinary antibiotics, loss of weight, night sweats and often coughing up blood.

In the past TB could only be diagnosed by culturing the tubercle bacillus, a process that takes 6 weeks. Now with modern technology there is a polymerase chain reaction test (PCR) so that diagnosis only takes a matter of days (the sample needs to be sent to the reference laboratory).

BCG(Bacille Calmette-Guerin) is a weakened form of the tubercle bacillus. There is some debate about how effective it is, but it definetely reduces the more serious forms of TB like tuberculous meningitis.

The first effective drug treatment for TB was streptomycin. This was proven to work in the very first prospective randomised trial (where patients get a treatment or control on a random basis). Before this patients would have treatments to collapse the lung (tubercle bacillus needs air - this is why the BCG vaccination can't be submerged in water) - ribs would be taken away, the lung punctured and the nerve to the diaphragm crushed or plastic balls inserted into the chest.