In this article, we will discuss the Pathology of Tubercular Meningitis. So, let’s get started.
The disease commonly involves the basal meninges. Secondary involvement of vessels (vasculopathy) and parenchymal lesions of the brain are equally characteristic and are important clinically.
1. Basal meningeal exudate involves the cranial nerves (palsy) at the base of brain (II, III, IV, VI, VII, VIII) to a varying degree.
2. Underlying encephalitis: In the region of meningeal exudate, there is underlying encephalitis. TBM is thus pathologically a meningoencephalitis rather than meningitis.
3. Vasculopathy: Blood vessels of all types (artery, capillary and veins) are involved in vasculopathy associated with meningitis. The brunt is more on the arteries, and the lesions include periarteritis, fibrinoid necrosis, panarteritis (panvasculitis with intimal proliferation and luminal narrowing). Focal and diffuse ischemic brain changes develop due to occlusion of both small and medium-sized cerebral arteries.
4. Tuberculoma formation: The site of tuberculoma is commonly the cerebellum in children and cerebral hemispheres in adults.
5. Hydrocephalus: A communicating hydrocephalus is common, develops due to blockage of basal cisterns in interpeduncular fossa by dense exudate or granulation tissue. At times, the obstruction may develop at the level of interventricular foramine, aqueduct of sylvius or foramina of Luschka and Magendie.
6. Tuberculous encephalopathy has been described in children where there is diffuse brain involvement due to perivascular demyelination with extensive oedema in the absence of above-mentioned pathological phenomenon to tuber-culo-protein.