Meningitis is inflammation of the brain meninges, which are membranes covering the brain. There are many forms of meningitis caused by viruses, bacteria or even yeasts, many of them are life-threatening. If the infection affects both meninges and brain tissue, we speak about meningoencephalitis.
The infection may be caused by various microorganisms, typically by viruses and bacteria. The most known and clinically important infectious agents are pneumococcus, meningococcus and haemophilus. The risk factors include weakened immune system and open head injuries. The infection can also enter the meninges from nearby tissues (sinusitis, skin abscesses on the face, etc.).
The inflammation of meninges causes their irritation and emergence of the so-called menigeal syndrome. The syndrome includes painful stiff neck (inability to bend the head forward), headache, nausea, vomiting, photophobia, dizziness, high fever and muscle cramps. More severe cases include unconsciousness.
The suspicion of meningitis is high when the above-mentioned symptoms combine with positive physical examination (stiff neck, inability to bend the head, etc). Blood tests usually show signs of infection such as elevated leukocytes and CRP. However, it should be noted that the meningitis can develop so rapidly that the body does not manage to start any defensive reaction and the blood tests show no pathology. Computed tomography or magnetic resonance imaging of the brain usually shows no typical finding, but they are good at exclusion of other pathologies (brain bleeding, brain tumors, etc.). Spinal tap is necessary for the right diagnosis as the obtained sample of cerebrospinal fluid not only proves the infection but also allows specifying the infectious agent and its sensitivity to antibiotics.
It there is suspicion of bacterial meningitis, the patient should get strong antibiotics as soon as possible. The antibiotics are administered intravenously and in large doses. The patients should be hospitalized in intensive care units with continuous monitoring of their vital signs. Corticosteroids may be given to reduce the risk of a brain edema.
Bacterial meningitides have usually worse prognosis than the viral, but when the treatment is started quickly, the patients have a high chance to survive. However, some people die no matter the therapy and others suffer from life-long consequences resulting from the brain damage (paralysis, speech disorders, deafness, personality changes, etc.).