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Home Your Health Multimedia Encyclopedia Meningitis - tuberculous

Meningitis - tuberculous

Definition

Tuberculous meningitis is an infection of the membranes covering the brain and spinal cord (meninges).

See also:

• Meningitis
• Meningitis - cryptococcal
• Meningitis - Gram-negative
• Meningitis - H. influenzae
• Meningitis - meningococcal
• Meningitis - pneumococcal
• Meningitis - staphylococcal

Alternative Names

Tubercular meningitis; TB meningitis

Causes, incidence, and risk factors

Tuberculous meningitis is caused by Mycobacterium tuberculosis, the bacteria that cause tuberculosis. The bacteria spread to the brain from another site in the body.

Risk factors include a history of:

• AIDS
• Excessive alcohol use
• Pulmonary tuberculosis
• Weakened immune system

Tuberculous meningitis is a very rare disorder in the U.S.

Symptoms

The symptoms usually begin gradually, and may include:

• Fever and chills
• Mental status changes
• Nausea and vomiting
• Sensitivity to light (photophobia)
• Severe headache
• Stiff neck (meningismus)

Other symptoms that can occur with this disease:

• Agitation
• Bulging fontanelles
• Decreased consciousness
• Poor feeding or irritability in children
• Unusual posture, with the head and neck arched backwards (opisthotonos)

Signs and tests

Physical examination will usually show:

• Fast heart rate
• Fever
• Mental status changes
• Stiff neck

For any patient who is suspected of having meningitis, it is important to perform a lumbar puncture ("spinal tap"), in which spinal fluid (known as cerebrospinal fluid, or CSF) is collected for testing. When the health care provider suspects tuberculous meningitis, more than one CSF sample may be needed to make the diagnosis.

Tests that may be done include:

• Biopsy of the brain or meninges
• Blood culture
• Chest x-ray
• CSF examination for cell count, glucose, and protein
• CT scan of the head
• Gram stain, other special stains, and culture of CSF
• Polymerase chain reaction (PCR) of CSF
• Skin test for tuberculosis (PPD)

Treatment

Treatment involves several antitubercular drugs at the same time, as it does for pulmonary tuberculosis. Treatment sometimes must begin if the diagnosis is only suspected, not proved, in order to save a person's life.

Treatment usually lasts for at least 12 months. Systemic steroids may also be used.

Support Groups

Expectations (prognosis)

Tuberculous meningitis is life-threatening if untreated. Long-term follow-up is needed to detect repeated infections (recurrences).

Complications

• Brain damage
• Build-up of fluid between the skull and brain (subdural effusion)
• Hearing loss
• Hydrocephalus
• Seizures

Calling your health care provider

Call the local emergency number (such as 911) or go to an emergency room if you suspect meningitis in a young child who has the following symptoms:

• Feeding problems
• High-pitched cry
• Irritability
• Persistent unexplained fever

Call the local emergency number if you develop any of the serious symptoms listed above. Meningitis can quickly become a life-threatening illness.

Prevention

In areas where tuberculosis is more common, the BCG vaccine may help prevent severe forms of tuberculosis, such as meningitis, in very young children.

Treating people who have evidence of a non-active (dormant) tuberculosis infection can prevent the spread of tuberculosis. A dormant infection can be detected by a positive PPD.

References

Iseman MD. Tuberculosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 345.

Swartz MN. Meningitis: bacterial, viral, and other. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 437.