Meningitis - tuberculous

Definition

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

Causes

Tuberculous meningitis is caused by Mycobacterium tuberculosis, the bacteria that cause tuberculosis. The bacteria spread to the brain and spine 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 in babies
• Decreased consciousness
• Poor feeding or irritability in children
• Unusual posture, with the head and neck arched backwards (opisthotonos)

Exams and Tests

The doctor or nurse will examine you. This will usually show:

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

A lumbar puncture ("spinal tap") is an important test in diagnosing meningitis. This test is done to collect a sample of spinal fluid for examination. More than one sample may be needed to make the diagnosis.

Other 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)
• Other tests to look for tuberculosis

Treatment

You will be given several medicines to fight the tuberculosis bacteria. Sometimes, treatment is started even if your doctor thinks you have the disease, but testing hasn't confirmed it yet.

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

Outlook (Prognosis)

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

Possible Complications

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

When to Contact a Medical Professional

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

The BCG vaccine may help prevent severe forms of tuberculosis, such as meningitis, in very young children who live in areas where the disease is common.

Treating people who have signs of a non-active (dormant) tuberculosis infection can prevent the spread of tuberculosis. A PPD test and other tuberculosis tests can be done to tell if you have this type of infection.