Infecções neurológicas

A brain abscess is an encapsulated, purulent collection of infection within the brain tissue. It develops on a background of adjacent focal infections (sinusitis, otitis media, dental infection), hematogenous spread, trauma-surgery or immunosuppression. The most common organisms are streptococci. Its typical features are headache, fever and focal neurological deficit. Diagnosis is made with contrast-enhanced brain MRI, and treatment is usually a combination of antibiotics and surgical drainage.

Spinal epidural abscess is a serious infection requiring urgent evaluation, characterized by a purulent collection in the epidural space of the spinal canal. It usually develops through hematogenous spread, spread from adjacent structures or after spinal procedures. The classic triad is back pain, fever and neurological deficit, although the full triad is seen in a minority of patients. Without early diagnosis and treatment it can lead to permanent neurological damage.

Pott disease is the most common form of spinal tuberculosis, developing when the bacterium Mycobacterium tuberculosis infects the vertebrae. It usually arises from hematogenous spread of pulmonary tuberculosis to the spine and most often involves the thoracolumbar region. Its characteristic features are vertebral collapse (gibbus deformity), paravertebral cold abscesses and neurological compression. Treatment is anti-tuberculosis drug therapy lasting 12-18 months, with surgery added in selected cases.

Meningitis is inflammation of the membranes (meninges) that surround the brain and spinal cord. It can develop from bacterial, viral, fungal or parasitic causes. Bacterial meningitis is the most serious form and, if not treated urgently, can lead to death or permanent neurological damage within hours to days; viral meningitis usually follows a milder course. The classic triad is fever, headache and neck stiffness. Diagnosis is made by lumbar puncture and analysis of the cerebrospinal fluid (CSF).

Encephalitis is inflammation of the brain tissue (parenchyma) and can develop from viral, bacterial, fungal or parasitic causes or from autoimmune mechanisms. Viral encephalitis is the most common form; Herpes Simplex Virus (HSV) is the most important sporadic cause and carries the highest mortality and morbidity. Typical features are fever, headache, altered consciousness, seizures and focal neurological deficit. When suspected, urgent aciclovir treatment should be started without waiting for a diagnosis.