Meningitis - tuberculous
Tubercular meningitis; TB meningitis
Tuberculous meningitis is an infection of the tissues covering the brain and spinal cord (meninges).
The organs of the central nervous system (brain and spinal cord) are covered by connective tissue layers collectively called the meninges. Consisting of the pia mater (closest to the CNS structures), the arachnoid and the dura mater (farthest from the CNS), the meninges also support blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.
The organs of the central nervous system (brain and spinal cord) are covered by 3 connective tissue layers collectively called the meninges. Consisting of the pia mater (closest to the CNS structures), the arachnoid and the dura mater (farthest from the CNS), the meninges also support blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.
Causes
Tuberculous meningitis is caused by Mycobacterium tuberculosis. This is the bacterium that causes tuberculosis (TB). The bacteria spread to the brain and spine from another place in the body, usually the lung.
Tuberculous meningitis is very rare in the United States. Most cases are in people who traveled to the United States from other countries where TB is common.
People who have the following have a higher chance of developing tuberculous meningitis:
- HIV/AIDS
- Drink alcohol in excess
- TB of the lung
- Weakened immune system
Symptoms
The symptoms often start slowly, 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 may include:
- Agitation
- Bulging fontanelles (soft spots) in babies
- Decreased consciousness
- Poor feeding or irritability in children
- Unusual posture, with the head and neck arched backward (opisthotonos). This is usually found in infants (less than 3 months old)
Exams and Tests
The health care provider will examine you. This will usually show that you have the following:
- Fast heart rate
- Fever
- Mental status changes
- Stiff neck
A lumbar puncture (spinal tap) is an important test in diagnosing meningitis. It 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 (rare)
- Blood culture
- Chest x-ray
- Cerebrospinal fluid (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 TB (PPD)
- Other tests to look for TB
Treatment
You will be given several medicines to fight the TB bacteria. Sometimes, treatment is started even if your provider thinks you have the disease, but testing has not confirmed it yet.
Treatment usually lasts for at least 12 months. Medicines called corticosteroids may also be used.
Outlook (Prognosis)
Tuberculous meningitis is life threatening if untreated. Long-term follow-up is needed to detect recurring infections.
Possible Complications
Untreated, the disease can cause any of the following:
- Brain damage
- Build-up of fluid between the skull and brain (subdural effusion)
- Hearing loss
- Hydrocephalus (buildup of fluid inside the skull that leads to brain swelling)
- Seizures
- Death
When to Contact a Medical Professional
Call 911 or the local emergency number 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
Treating people who have signs of a non-active (dormant) TB infection can prevent its spread. A PPD test and other TB tests can be done to tell if you have this type of infection.
Some countries with a high incidence of TB give people a vaccine called BCG to prevent TB. But, the effectiveness of this vaccine is limited, and it is not usually used in the United States. The BCG vaccine may help prevent severe forms of TB, such as meningitis, in very young children who live in areas where the disease is common.
References
Cruz AT, Starke JR. Tuberculosis. In: Cherry JD, Harrison GJ, Kaplan SL, Steinbach WJ, Hotez PJ, eds. Feigin and Cherry's Textbook of Pediatric Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 96.
Ellner JJ, Jacobson KR. Tuberculosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 308.
Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 249.
Version Info
Last reviewed on: 12/4/2022
Reviewed by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
