Meningitis can have various causes such as infection with bacteria or virus, chemical irritation, drug allergies, fungal infections and brain tumour. Prognosis for meningitis depends on the underlying cause and severity of infection. In the initial phase of illness, the doctor may not be able to tell the exact prognosis or outlook.
Prognosis of bacterial meningitis
Bacterial meningitis is considered a medical emergency as it can progress rapidly and lead to septicaemia (blood poisoning), brain damage or even be fatal despite of the availability of the most advanced medical care. Timely treatment with appropriate antimicrobial and supportive therapy in acute bacterial meningitis can improve prognosis. Besides this, the prognosis depends on several other factors such as age, presence of comorbidity, causative pathogen, and severity at presentation.
Neurologic problems such as permanent mental impairment, paralysis, seizures and hearing loss occur in about 15% of children, who survive bacterial meningitis. About 20% of children may experience more subtle adverse outcomes such as cognitive, academic and behavioural problems. In adults, about 30% develop cognitive impairment.
Bacterial meningitis results in death in about 4 to 10% of children and about 25% of adults with meningitis. Death rate in two of the most common bacteria that cause meningitis are 3% to 7% in Haemophilus influenzae meningitis and about 20% to 25% in Streptococcus pneumonia meningitis.
Prognosis of viral meningitis
The prognosis for viral meningitis is good in most cases. The patient recovers with treatment in about 7-10 days. Besides tests, the self-limiting nature of a disease can help make the diagnosis of viral meningitis, however, the prognosis is not so good in neonates and infants in whom viral meningitis can be fatal or associated with significant morbidity. If the patient develops encephalitis (brain gets infected with the virus) or other complications such as pericarditis and hepatitis, prognosis becomes poor.
Prognosis of other types of meningitis depends on underlying cause such as if the brain tumour can be removed and the patient may improve significantly.