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MENINGITIS

Viral meningitis
Once a diagnosis of viral meningitis has been made the symptoms generally start to settle down over the course of 24 to 48 hours and recovery is complete after one to four weeks, although tiredness can last for longer.

Bacterial meningitis
When bacterial meningitis has been suspected and treatment started early there is usually a gradual improvement in symptoms over the first 48 to 72 hours. In young children the response to treatment can be quite dramatic even within 24 hours. Even though the headache and fever settle relatively quickly in uncomplicated meningitis, bacterial meningitis can cause nerve damage (e.g. deafness), occasionally stroke, epilepsy, or raised pressure inside the head, and dealing with these can be difficult and take a long time.

POSSIBLE COMPLICATIONS

Deafness
Bacterial meningitis of any type can lead to deafness due to inflammation of the auditory or acoustic nerves. Early treatment of haemophilus meningitis with steroids may reduce the likelihood of this complication. Hearing in children is usually tested about one month after recovery from bacterial meningitis.

Epilepsy
Epilepsy occurs in between five and 30 per cent of patients with encephalitis or meningitis and up to 50 per cent of patients with a cerebral abscess. Epileptic attacks may take the form of major fits, but minor attacks with loss of awareness of surroundings or confused behaviour for a minute or so are more common, especially in HSE.

Hydrocephalus
Blockage to the CSF pathways due to pus can result in expansion of the normal fluid-filled sacks within the brain (hydrocephalus). This causes raised pressure inside the skull and may require a surgical procedure in which the fluid is drained off via a piece of tubing or shunt insertion.

Cerebral oedema
Severe encephalitis or meningitis can cause brain swelling (oedema) and coma. Monitoring of the brain pressure, powerful diuretic drugs, steroids, artificial ventilation and treatment for the coma may be needed.

Brain damage
Severe HSE and cerebral abscesses can cause permanent brain damage, and bacterial meningitis can cause strokes due to blockage of the blood vessels going to part of the brain. In the most extreme cases this can result in persistent vegetative state. In this condition the person has no understanding of what is happening and is unable to communicate. More commonly, the brain damage can lead to persistent changes in personality,memory loss, weakness on one side of the body, speech problems or epilepsy.

Death
Brain abscesses are fatal in 40 per cent of cases, pneumococcal meningitis leads to death in 20 to 30 per cent of patients, while fatalities fall to five to 10 percent with meningococcal meningitis and herpes simplex encephalitis if treated, and up to five per cent in the case of haemophilus influenza meningitis.

ENCEPHALITIS

Herpes simplex encephalitis (HSE)
Treatment of HSE is started immediately after an assessment of a person's symptoms but confirmation of the diagnosis may take weeks or months. Usually people show some response to treatment in the first 48 to 72 hours. Usually, the fever comes down and there is some improvement in their level of awareness, and they become less agitated.

If the memory has been affected, or if HSE has caused weakness, unusual sensations or has affected speech, these will take weeks or months to recover. Subtle memory difficulties can continue indefinitely. Fits usually come under control once treatment with anticonvulsants has been started and the infection settles. Up to 50 per cent of people with epilepsy will be troubled by recurrent fits despite anticonvulsants, but these are generally infrequent. Lifelong anticonvulsant treatment may be needed.

In severe HSE, or where treatment has been delayed, improvement may be very slow and incomplete. Most improvement takes place in the first three months after HSE occurs, but it can continue at a slower rate for up to a year.

Encephalitis linked to childhood viruses
Viral encephalitis related to the common viruses which cause rashes is generally less severe. Recovery from the clumsiness and unsteadiness which are associated with encephalitis is usually complete after four weeks. In severe cases a slower recovery may take up to a year.