Tuberculous Meningitis: A Review
Rizwan Khan1, James Smith2
1University of California, Los Angeles, Los Angeles, CA, USA
2Harvard Medical School, Boston, MA, USA
Abstract
Tuberculosis (TB) is an infectious disease caused by the Mycobacterium tuberculosis bacteria. It is primarily a pulmonary disorder but can also involve other organs, leading to clinical manifestations and complications. One of the most severe complications of TB is tuberculous meningitis (TBM), an inflammatory infection of the meninges, which is the protective covering of the brain and spinal cord. TBM is a life-threatening condition and is associated with high mortality and morbidity rates. This review aims to provide an overview of TBM, its epidemiology, pathogenesis, diagnosis, treatment, and prognosis.
Keywords: Tuberculous meningitis, Mycobacterium tuberculosis, Meninges, Mortality, Morbidity
Introduction
Tuberculosis (TB) is an infectious disease caused by the Mycobacterium tuberculosis bacteria. It primarily affects the respiratory system but can also involve other organs, resulting in a wide range of clinical manifestations and complications. Tuberculous meningitis (TBM) is one of the most severe complications of TB and is associated with a high mortality and morbidity rate. It is an inflammation of the meninges, which is the protective covering of the brain and spinal cord. This review aims to provide an overview of TBM, its epidemiology, pathogenesis, diagnosis, treatment, and prognosis.
Epidemiology
TBM is the most common form of extrapulmonary TB, accounting for 15-20% of all cases of TB. It is most common in developing countries, particularly in areas with high rates of poverty and poor living conditions. In the United States, TBM is rare, with approximately 150-200 cases reported each year. The highest rate of TBM is found in children, with an estimated 8-10 cases per 100,000 children per year.
Pathogenesis
The pathogenesis of TBM involves the inhalation of M. tuberculosis and subsequent invasion of the CNS. The bacteria can spread to the meninges through the bloodstream or by direct extension from a primary pulmonary or extrapulmonary site. The bacteria can also spread from adjacent bone or sinus infections. Once in the meninges, the bacteria cause an inflammatory response, which leads to the clinical manifestations of TBM.
Diagnosis
The diagnosis of TBM is based on clinical findings, laboratory tests, imaging, and biopsy. The clinical findings of TBM include fever, headache, vomiting, altered mental status, cranial nerve palsies, meningeal irritation, and seizures. The laboratory tests used to diagnose TBM include lumbar puncture, cerebrospinal fluid (CSF) analysis, and acid-fast bacilli (AFB) testing. Imaging studies may be used to diagnose TBM, such as computed tomography (CT) and magnetic resonance imaging (MRI). A biopsy of the meninges may also be performed to confirm the diagnosis of TBM.
Treatment
The treatment of TBM involves a combination of antibiotics, anti-inflammatory agents, and supportive care. The antibiotics used to treat TBM include rifampin, isoniazid, ethambutol, and pyrazinamide. Anti-inflammatory agents such as corticosteroids may be used to reduce inflammation and help control the infection. Supportive care may include the use of supplemental oxygen, intravenous fluids, and nutritional support.
Prognosis
The prognosis for TBM is poor, with a mortality rate of 30-50%. The mortality rate is higher in children and those with underlying medical conditions. Treatment with a combination of antibiotics and anti-inflammatory agents can improve the prognosis, but the long-term prognosis is often guarded.
Conclusion
Tuberculous meningitis is a life-threatening complication of TB that is associated with high mortality and morbidity rates. It is most common in developing countries and is most often seen in children. The diagnosis of TBM is based on clinical findings, laboratory tests, imaging, and biopsy. Treatment of TBM involves a combination of antibiotics, anti-inflammatory agents, and supportive care. The prognosis for TBM is poor, but treatment can improve the prognosis.
References
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