Page 312 - Medicine and Surgery

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308 Chapter 7: Nervous system

Investigations Management
Leucocytosis and a raised ESR are common. Anti-tuberculous therapy as for tuberculous meningitis
The diagnosis is made by CT or MRI scanning, but should be used (see page 303) but is often unsuccessful,

there may be non-specific oedema in the early stages. in which case surgical drainage may be used.
Later, ring-enhancement demonstrates the break-
down in blood-brain barrier.
Inmostcaseslumbarpunctureiscontra-indicateddue
Disorders of conciousness
to risk of brain-stem herniation (coning), but aspira- and memory
tion or excision biopsy of the abscess may be carried
out by a neurosurgeon if the organism is in doubt. Epilepsy
Fungi and mycobacteria must be looked for.
Definition
Epilepsy is a recurrent tendency to seizures. Seizures are
Management
due to paroxysmal discharge of cerebral neurones.
Frequently treatment is by a combination of antimicro-
bial therapy and surgical drainage.
Incidence
Approximately 2% have two or more seizures during
Prognosis their lives.
25% mortality despite treatment, epilepsy is common in
survivors. Age
Any

Tuberculoma Sex
M = F
Definition
Atuberculoma is a localised caseous abscess within Aetiology
the brain caused by M. tuberculosis.Itisrareinthe A cause for epilepsy is found in less than 25% of cases.
West, but the commonest single intracranial lesion in Most of the others are thought to be genetically deter-
India. mined.
About 30% have an affected first degree relative.

Head trauma: minimal risk if <30 minutes concus-

Aetiology/pathophysiology
sion, high risk if there is contusion, haemorrhage or
Atuberculoma is a chronic caseating intracranial granu-
prolonged amnesia.
loma, which may arise from haematogenous spread dur- Surgery to the cerebral hemispheres is followed by
ing primary TB, e.g. miliary TB.
epilepsy in 10%.
Perinatal trauma and fetal anoxia are common causes

Clinical features of seizures in childhood.
Intracranial mass lesions affecting the cerebral cortex
The condition is often asymptomatic as they are rarely
large enough to cause symptoms of an intracranial mass e.g tumours.
lesion. Rupture into the subarachnoid space may cause Vascular malformations.
tuberculous meningitis. A tuberculoma in the brainstem Cerebral infarction particularly in the elderly.
may cause hydrocephalus by obstruction. Drugs, alcohol, drug withdrawal.
Inborn errors of metabolism.

Investigations Clinical features
Lesion may be seen on X-ray as an area of internal cal- Epilepsy is most often diagnosed on the history, from
cification, or on CT/MRI. Skin testing, e.g. Mantoux is witnesses (see Table 7.7). Features suggestive of a fit are
not reliable. described under Fits and Faints (see page 287).