Tuberculosis (TB) is an infectious disease caused by a bacterium called Mybacterium Tuberculosis (MTB). It usually affect the lungs. With time, the bacterium can spreads to other parts of the body including the brain. TB can affect people all ages and sexes.
In the brain, tuberculosis forms what we call a tuberculoma. Tuberculomas vary in size and shape. They may be single or multiple. In the mature form, a tuberculoma is firm, hard to touch, and grayish-yellow in color. Tuberculoma usually does not contain any blood vessel. A capsule of tuberculoma is a piece of compressed, damaged brain tissue. A neurosurgeon’s job is to take out these tuberculomas.
Types of Tuberculoma
If the TB proves difficult to deal with medically, then a neurosurgeon works on physically removing the tuberculomas from the brain. To do that, it is important to know what kind of tuberculoma one is dealing with.
- Tuberculoma en plaque
This tuberculoma looks like a plaque. This type of tuberculoma has increased blood vessels (other tuberculomas don’t have blood vessels). Surgeon must keep this in mind while removign the plaque-like tuberculomas.
- Tuberculous Abscess
These tuberculomas contain pus and resemble a brain abscess. This type of tuberculoma is common in India
- Cystic Tuberculoma
These tuberculoma are in the form of a cyst. They are filled with clear yellow or cloudy green fluid, depending on the stage of infection. These tuberculomas are relatively rare.
- Multiple Grape-like Tuberculomas
Very rarely, multiple, immature tuberculomas are observed. They group together, resembling a cluster of grape.
This type of tuberculoma is seen as a small disc or ring around 5mm to 7mm in diameter. These are common in India.
- Calcified Tuberculomas
With time, a tuberculoma can calcify into a hard mass. Although calcified, they are still infectious.
- Tuberculous Encephalopathy with an “Inconsequential” Tuberculoma
Sometimes, brain damage is seen in children with a small or no lession at all. This is usually because of an allergic reaction to some proteins relseased by the TB bacteria. In these cases, a biopsy of the brain tissue usually help to confirm the presence of TB.
Here are some of the common symptoms of Brain TB:
- Gait problems
- Speech Disturbances
- Vision Problems
- History of exposure to lung TB
- Evidence of TB elsewhere in the body
Here is the usual set of investigations carried out to find out of one has TB and how it has affected the body.
- Blood Test
ESR (Erythrocyte Sedimentation Rate) is usually raised when there is any kind of infection in the body, including TB. So, a doctor orders a blood test to determine the ESR. But TB is a tricky one. One can have TB even with normal ESR.
- Mantoux Test
A protein component of TB bacteria is injected into the skin of the forearm. If one has TB, the injection site becomes red in color. Trouble with this test is that it can give false-positive results.
- Chest X-Ray
TB very rarely occurs without a lung infection. So, when the doctor suspects presence of TB, they always order a Chest X-Ray to determine if there is evidence of TB in the lungs.
- CT of the Brain
CT imaging of the brain helps the doctor/surgeon to idenitfy she size, shape, location and number of lesions (damaged patches of tissue) in the brain. CT can also visualize calcification clearly.
- MRI of the Brain
MRI images help the doctor/surgeon to see the stages of brain lesions clearly.
- Stereotactic Biopsy
Under the CT guidance, using a fine needle, a small portion of the affected brain tissue (lesion) is taken out and studied under a microscope. This help in definitive diagnosis of TB in the brain.
Treatment of the Brain TB
Doctors usually prefer to deal with TB medically. When that fails, or when the TB has already spread dangerously, a decision to surgically remove the TB affected tissue is preferred.
Medication that kill or stop the growth of TB bacteria are known as anti0tubercular drugs. Usually, an anti-tuberculor drug, combined with steroidal medications, lead to healing of the TB affected tissue in 10 to 12 weeks’ time. If the patch of affected tissue is large, then complete healing might take up to 6 to 8 months.
- Small and easily accessible tuberculomas (tissue hardened by TB) can be removed by excision.
- With large tuberculomas, an ultrasonic aspirator (or CUSA) is used to suck out the TB affected tissue, without affecting the surrounding normal area.
Go here for more information on surgical treatment of Brain TB.