Infections of the brain are common in developing countries. These can have devastating consequences if not managed timely and appropriately. These include tuberculosis, fungal infections, bacterial and neurocysticercosis.
While medical management is the essence of treatment in the majority, in few patients surgery is required to remove large lesions which are not responding to medications, in whom the diagnosis is doubtful and in whom medical management is not very effective (as intraventricular cysticercosis
Tuberculosis involves the central nervous system. Varied presentations include meningitis, vasculitis resulting in stroke, hydrocephlaus (post-meningitic), tubercular abscesses, tuberculomas presenting as mass effect and raised intracranial pressures. While anti-tubercular treatment remains the mainstay of treatment, surgery is required for patients with doubtful diagnosis, no radiological response to medications, and to relieve the raised intracranial pressure as in hydrocephalus and tuberculomas / abscesses.
2. Fungal infections:
Fungal brain abscesses are the most common intracranial presentation. With increasing geriating population, associated co-morbidities as diabetes mellitus, immunosuppressive conditions as long-term steroid treatment, malignancies, the incidence of fungal infections has risen significantly. Radiologically, there are no specific features to diagnose these infections. Most often, patients present with features of raised inctracranial pressure and diagnosis is made on microbiological and histological analysis following surgical excision of the lesion. Medical management has become safer with availability of newer antifungals as Voriconazole which has good compliance, minimal drug interactions and side effects and good tolerance.
3. Parasitic infections as neurocysticercosis:
Cysticercosis is an endemic condition in developing countries. While majority of patients present with seizures, few present with raised intracranial pressure. Intra-ventricular cysticercosis
presents with obstructive hydrocephalus and surgery is the method of choice for these patients. Endoscopes can be used effectively to remove intraventricular lesions when they present with hydrocephalus.
4. Bacterial abscesses:
Pyogenic brain abscesses present with fever, headache, vomitting, focal neurological deficit and unconsciousness. Penetrating head injury, compound depressed bone fractures, bacteremias, septic emboli from infected valves, devices, adjacent infections as chronic suppurative otitis media are some of the common causes of pyogenic brain abscesses. Treatment includes parenteral antibiotics, removing the source of infection, and surgical drainage in those with raised intracranial pressure.
CNS infections can have devastating results if there is delay in diagnosis and treatment. Prompt diagnosis and treatment results in good neurological outcomes.