Infection of the nervous system

The clinical features of nervous system infection depend on the location of the infection [the meanings or the parenchyma of the brain and spinal cord], the causative organism [virus, bacteria, fungus or parasite] and whether the infection is acute or chronic The clinical features of nervous system infection depend on the location of the infection [the meanings or the parenchyma of the brain and spinal cord], the causative organism [virus, bacteria, fungus or parasite] and whether the infection is acute or chronic

meningitis Acute infection of meninges present with a characteristic combination of pyrexia, headache and meningism. Acute infection of meninges present with a characteristic combination of pyrexia, headache and meningism. Meningism; consist of headache, photophopia and stiffness of neck, often accompanied by other meningeal irritation signs [kernig ’ s sign and Brudzinski ’ s] Meningism; consist of headache, photophopia and stiffness of neck, often accompanied by other meningeal irritation signs [kernig ’ s sign and Brudzinski ’ s]

Viral meningitis Viral infection is the most common cause of meningitis, and usually results in a benign and self-limiting illness requiring no specific therapy. It is a much less serious illness than bacterial meningitis unless there is associated encephalitis, which is rare. the most common being enterovirus and, where specific Viral infection is the most common cause of meningitis, and usually results in a benign and self-limiting illness requiring no specific therapy. It is a much less serious illness than bacterial meningitis unless there is associated encephalitis, which is rare. the most common being enterovirus and, where specific is not employed immunization, the mumps is not employed immunization, the mumps virus virus

Clinical features The condition occurs mainly in children or young adults, with acute onset of headache and irritability and the rapid development of meningism. In viral meningitis, the headache is usually the more severe feature. There may be a high pyrexia, but focal neurological signs rarely occur The condition occurs mainly in children or young adults, with acute onset of headache and irritability and the rapid development of meningism. In viral meningitis, the headache is usually the more severe feature. There may be a high pyrexia, but focal neurological signs rarely occur

Investigations The CSF usually contains an excess of lymphocytes, but glucose and protein levels are commonly normal or the protein level may be raised. It is extremely important to verify that the patient has not received antibiotics (for whatever cause) prior to the lumbar puncture, as this picture can also be found in partially treated bacterial meningitis The CSF usually contains an excess of lymphocytes, but glucose and protein levels are commonly normal or the protein level may be raised. It is extremely important to verify that the patient has not received antibiotics (for whatever cause) prior to the lumbar puncture, as this picture can also be found in partially treated bacterial meningitis

Management There is no specific treatment and the condition is usually benign and self-limiting. The patient should be treated symptomatically in a quiet environment. Recovery usually occurs within days, although a lymphocytic pleocytosis may persist in the CSF. Meningitis may also occur as a complication of a viral infection primarily involving other organs: for example, in mumps, measles, infectious mononucleosis, herpes zoster and hepatitis. Complete recovery without specific therapy is the rule. There is no specific treatment and the condition is usually benign and self-limiting. The patient should be treated symptomatically in a quiet environment. Recovery usually occurs within days, although a lymphocytic pleocytosis may persist in the CSF. Meningitis may also occur as a complication of a viral infection primarily involving other organs: for example, in mumps, measles, infectious mononucleosis, herpes zoster and hepatitis. Complete recovery without specific therapy is the rule.

Bacterial meningitis Many bacteria can cause meningitis. Certain organisms are particularly common at different age ranges. Bacterial meningitis is usually secondary to a baceraemic Many bacteria can cause meningitis. Certain organisms are particularly common at different age ranges. Bacterial meningitis is usually secondary to a baceraemic illness, although infection may result from direct spread from an adjacent focus of infection in the ear, skull fracture or sinus. Bacterial meningitis has become less common but the mortality and morbidity remain significant despite the availability of an increasing range of antibiotics. An important factor in determining prognosis is early diagnosis and the prompt initiation of appropriate therapy illness, although infection may result from direct spread from an adjacent focus of infection in the ear, skull fracture or sinus. Bacterial meningitis has become less common but the mortality and morbidity remain significant despite the availability of an increasing range of antibiotics. An important factor in determining prognosis is early diagnosis and the prompt initiation of appropriate therapy

The meningococcus (Neisseria meningitidis) is now second to Streptococcus pneumoniae as the most common cause of bacterial meningitis in Western Europe, whilst in the USA, Haemophilus influenzae remains common. In India, Haemophilus influenzae B and Streptococcus pneumoniae are probably the most common causes of bacterial meningitis, at least in children The meningococcus (Neisseria meningitidis) is now second to Streptococcus pneumoniae as the most common cause of bacterial meningitis in Western Europe, whilst in the USA, Haemophilus influenzae remains common. In India, Haemophilus influenzae B and Streptococcus pneumoniae are probably the most common causes of bacterial meningitis, at least in children L. monocytogenes) has become an increasingly important cause of meningitis in neonates ( 60 years, and immunocompromised individuals of all ages. Infection is acquired by ingesting foods contaminated by Listeria. Foodborne human listerial infection has been reported from contaminated coleslaw, milk, soft cheeses, and several types of "ready-to-eat" foods, including delicatessen meat and uncooked hotdogs. L. monocytogenes) has become an increasingly important cause of meningitis in neonates ( 60 years, and immunocompromised individuals of all ages. Infection is acquired by ingesting foods contaminated by Listeria. Foodborne human listerial infection has been reported from contaminated coleslaw, milk, soft cheeses, and several types of "ready-to-eat" foods, including delicatessen meat and uncooked hotdogs.

Clinical features Headache, drowsiness, fever and neck stiffness are the usual presenting features. In severe bacterial meningitis the patient may be comatose and later there may be focal neurological signs. Meningococcal meningitis is associated with a purpuric rash in 70% of cases. When accompanied by septicaemia, it may present very rapidly, with abrupt onset of obtundation due to cerebral oedema, probably as a result of endotoxin and/or cytokine release, and circulatory collapse Headache, drowsiness, fever and neck stiffness are the usual presenting features. In severe bacterial meningitis the patient may be comatose and later there may be focal neurological signs. Meningococcal meningitis is associated with a purpuric rash in 70% of cases. When accompanied by septicaemia, it may present very rapidly, with abrupt onset of obtundation due to cerebral oedema, probably as a result of endotoxin and/or cytokine release, and circulatory collapse

investigation Lumbar puncture is mandatory unless there are contra-indications (). Lumbar puncture is mandatory unless there are contra-indications (). Particularly if the patient is drowsy with focal neurological signs or seizures, it is wise to obtain a CT to exclude a mass lesion (such as a cerebral abscess) before lumbar puncture because of the risk of coning, but this should not delay treatment of a presumptive meningitis. If lumbar puncture is deferred or omitted, it is essential to take diagnostic specimens and to start empirical treatment (In bacterial meningitis the CSF is cloudy (turbid) due to the presence of many neutrophils (often > 109 cells/litre), the protein content is significantly elevated and the glucose reduced. Gram film and culture may allow identification of the organism. Blood cultures may be positive. Polymerase chain reaction (PCR) techniques can be used on both blood and CSF to identify bacterial DNA. These methods are useful in detecting meningococcal infection and in typing the organis Particularly if the patient is drowsy with focal neurological signs or seizures, it is wise to obtain a CT to exclude a mass lesion (such as a cerebral abscess) before lumbar puncture because of the risk of coning, but this should not delay treatment of a presumptive meningitis. If lumbar puncture is deferred or omitted, it is essential to take diagnostic specimens and to start empirical treatment (In bacterial meningitis the CSF is cloudy (turbid) due to the presence of many neutrophils (often > 109 cells/litre), the protein content is significantly elevated and the glucose reduced. Gram film and culture may allow identification of the organism. Blood cultures may be positive. Polymerase chain reaction (PCR) techniques can be used on both blood and CSF to identify bacterial DNA. These methods are useful in detecting meningococcal infection and in typing the organis

Patient with clear history of B-latcam anaphylaxis Patient with clear history of B-latcam anaphylaxis Chloramphenicol 25mg/kg iv 4 times daily plus vancomycin 1gm iv twice daily Chloramphenicol 25mg/kg iv 4 times daily plus vancomycin 1gm iv twice daily

TUBERCULOUS MENINGITIS Now rare in developed countries in previously healthy individuals, tuberculous meningitis remains common in developing countries and is seen more frequently as a secondary infection in patients with AIDS Now rare in developed countries in previously healthy individuals, tuberculous meningitis remains common in developing countries and is seen more frequently as a secondary infection in patients with AIDS

Tuberculous meningitis occurs most commonly shortly after a primary infection in childhood or as part of miliary tuberculosis. The usual local source of infection is a caseous focus in the meninges or brain substance adjacent to the CSF pathway. The brain is covered by a greenish, gelatinous exudate, especially around the base, and numerous scattered tubercles are found on the meninges Tuberculous meningitis occurs most commonly shortly after a primary infection in childhood or as part of miliary tuberculosis. The usual local source of infection is a caseous focus in the meninges or brain substance adjacent to the CSF pathway. The brain is covered by a greenish, gelatinous exudate, especially around the base, and numerous scattered tubercles are found on the meninges

Clinical features

Stage 1[early];non-specific symptoms and signs and without alteration of cosicousness Stage 1[early];non-specific symptoms and signs and without alteration of cosicousness Stage 2 [intermediate]; altered consciousness without coma or delirium+ minor focal neurological signs Stage 2 [intermediate]; altered consciousness without coma or delirium+ minor focal neurological signs Stage 3[advance] ;stupor or coma; severe neurology deficit, seizure or altered movement Stage 3[advance] ;stupor or coma; severe neurology deficit, seizure or altered movement

investigations The CSF is under increased pressure. It is usually clear but, when allowed to stand, a fine clot ('spider web') may form. The fluid contains up to 5 × 108 cells/litre, predominantly lymphocytes. There is a rise in protein and a marked fall in glucose. Detection of the tubercle bacillus in a smear of the centrifuged deposit from the CSF may be difficult. The CSF should be cultured but as this result will not be known for up to 6 weeks, treatment must be started without waiting for confirmation. Brain imaging may show hydrocephalus, brisk meningeal enhancement on enhanced CT and/or an intracranial tuberculoma

As soon as the diagnosis is made or strongly suspected, chemotherapy should be started The use of corticosteroids in addition to antituberculous therapy has been controversial. Recent evidence suggests that it improves mortality but not focal neurological damage, especially if given early. Surgical ventricular drainage may be needed if obstructive hydrocephalus develops. Skilled nursing is essential during the acute phase of the illness, and measures should be put in place to maintain adequate hydration and nutrition. Prognosis Untreated tuberculous meningitis is fatal in a few weeks but complete recovery is the rule if treatment is started before the appearance of focal signs or stupor. When treatment is started at a later stage, the recovery rate is 60% or less and the survivors show permanent neurological deficit As soon as the diagnosis is made or strongly suspected, chemotherapy should be started The use of corticosteroids in addition to antituberculous therapy has been controversial. Recent evidence suggests that it improves mortality but not focal neurological damage, especially if given early. Surgical ventricular drainage may be needed if obstructive hydrocephalus develops. Skilled nursing is essential during the acute phase of the illness, and measures should be put in place to maintain adequate hydration and nutrition. Prognosis Untreated tuberculous meningitis is fatal in a few weeks but complete recovery is the rule if treatment is started before the appearance of focal signs or stupor. When treatment is started at a later stage, the recovery rate is 60% or less and the survivors show permanent neurological deficit