Meningitis is an infection which attacks the meninges, or covering, of the brain. Tuberculosis is an infection which is caused by Mycobacterium tuberculosis and will affect organs in the body that are the most highly oxygenated because this particular bacteria it requires a high amount of oxygen. These organs will include the upper lobes of the lungs, liver, kidney and the brain.
Tuberculosis is the seventh leading cause of death and disability in the world today. The 2003 Tuberculous Advocacy Report from the World Health Organization stated that 8 million new cases of tuberculosis are reported annually and 2 million deaths occur each year.
Tuberculosis meningitis is the most severe form of tuberculosis and affects the meninges of the brain. It can cause severe neurological deficits or even death in more than half of the cases diagnosed.
The cause of tuberculosis meningitis is from a tuberculosis infection in another site in the body. The bacteria will migrate to the meninges of the brain and cause a gradual increase in symptoms. Factors that increase the risk of developing tuberculosis meningitis include excessive alcohol use, a history of pulmonary tuberculosis, AIDS or other disorders that compromise the immune system.
The pattern of developing tuberculosis meningitis in a population is different in different areas of the world. Where tuberculosis is a common diagnosis, tuberculosis meningitis will usually affect young children developing three to six months after the primary infection. By contrast, in areas of the world with a lowered level of tuberculosis, tuberculosis meningitis tends to strike adults. In these cases it may follow primary infection, but more frequently is due to reactivation of an old infection that has remained dormant for many years.
Symptoms of the disease include seizures, fever, listlessness, loss of appetite, severe headache, stiff neck, sensitivity to light, nausea and vomiting and loss of consciousness. Physicians should have a high index of suspicion for early diagnosis of the disease. Only through early diagnosis and treatment is there a satisfactory outcome. If tuberculosis meningitis is seriously suspected then treatment should start immediately, even before definitive diagnosis has been reached.
The World Health Organization recommends a two month intensive course of medication followed by another four months to treat tuberculosis meningitis adequately. They have also found that the use of corticosteroids has improve survival in patients over the age of 14 but probably does not prevent severe disability.
Doctors will evaluate patients using a lumbar puncture (spinal tap), when a sample of spinal fluid is taken for lab testing. Other tests will also include a cerebral spinal fluid stain, measurements for protein in glucose, cerebral spinal fluid culture, positive brain or meningeal biopsy and a positive skin test for tuberculosis. But, as stated above, if the physician has a serious suspicion that tuberculosis meningitis is the cause for the symptoms, treatment should be instituted immediately.
Tuberculosis meningitis is fatal if left untreated and long-term follow-up is necessary to detect any recurrences or repeated infections. Even with treatment and medication individuals may suffer from brain damage which results from the infection that can cause paralysis, seizures, mental impairment and abnormal behavior.
Treatment will often begins with two months of intensive course of isoniazid, rifampin, pyrazinamide and ethambutol. Once those first two months of been completed patients will complete another four months with isoniazid and rifampin.
In areas of the world where tuberculosis is more common children are often given the BCG vaccine that can help prevent the more severe forms of tuberculosis, such as tuberculosis meningitis, in very young children. This vaccine will help to prevent the spread of the illness in young children but is not helpful in adults. The spread of tuberculosis can be prevented through treatment of individuals who have evidence of a nonactive tuberculosis infection as well as those who have active disease.
RESOURCES
Meningitis Research Foundation: TB MEningitis
MedlinePlus: Meningitis Tuberculosis
New England Journal of Medicine: Dexamethasone for the Treatment of Tuberculosis Meningitis in Adolescents and Adults
University of Maryland Medical Center: Meningitis Tuberculosis