BRAIN TUMOURS

BRAIN TUMOURSCauses

1) Metastases Breast, Stomach, Prostate, Thyroid, Kidney

2) Primary malignant tumors of neuroepithelial tissues Gliomas- Astrocytoma,Oligodendroglioma

Mixed (oligoastrocytomas) gliomas

Medulloblastoma

Ependymomas Primary cerebral lymphoma

Medulloblastoma

3) Benign Meningioma

Neurofibroma Metastases are the commonest intracranial tumoursClinical features Clinical features of cerebral tumors depend on location of tumor, rate of growth type of tumor, effect on CSF pathway.

Clinical features of brain tumors can be divided 1. Direct effect - brain is either destroyed locally or function is impaired

2. Secondary effects of raised intracranial pressure and shift of intracranial contents . 1) Direct effects of mass lesions

The focal deficits produced by a cerebral tumour are of insidious onset and progressive. The hallmark of a direct effect of a mass is progressive deterioration of function. Manifestations of direct effect include Generalized or partial seizures

Progressive hemi paresis, vague disturbance of personality, apathy and

Impaired intellect, expressive aphasia, homonymous field defect 2) Secondary effects of raised intracranial pressure and shift of intracranial contents

Headache, vomiting and papilloedema. These symptoms often imply hydrocephalus

False localizing signs - false only because they do not point directly to the site of the mass

1. A sixth nerve lesion, first on the side of a mass and later bilaterally - as the VI nerve is compressed during its long intracranial course.

2. A third nerve lesion develops as the temporal lobe uncus herniates caudally, compressing the third nerve against the petroclinoid ligament..

3. Hemiparesis on the same side as a hemisphere tumour (i.e. the side you would not expect) produced by compression of the contralateral cerebral peduncle within the brainstem on the free edge of the tentorium.3) Provoking either generalized or partial seizures.

Seizures are caused by infiltration by tumour cells of an area of cerebral cortex which excites seizure activity. The resulting seizures may be generalised or partial in natureInvestigations

CT or MRI of the head allows accurate localisation of the tumour MRI is of particular value in the investigation of tumours of the posterior fossa and brain stem MR angiography and MR spectroscopy are occasionally used to define changing size or blood supply.

Positron emission tomography (PET) is helpful in grading gliomas or locating an occult primary.

Biopsy Stereotactic biopsy via a skull burr-hole is usually carried out to ascertain the histology of a suspected malignancy

EEG -- rarely helps

Routine tests

Since metastases are common, routine tests, e.g. chest X-ray, should be performed.Management

A) Medical Raised intracranial pressure Dexamethasone, 8 mg 12-hourly either orally or by injection, is used to lower intracranial pressure by resolving the reactive oedema around a tumour. 20% solution of mannitol may be infused. Prolactin- or growth hormone-secreting pituitary tumours Treatment with the dopamine agonists bromocriptine, cabergoline or quinagolideB) Surgical

Surgery is the mainstay of treatment,

Meningiomas and acoustic neuromas offer the best prospects for complete removal without unacceptable damage to surrounding structures. .Pituitary adenomas can often be removed by a trans-sphenoidal routeC) Radiotherapy and chemotherapy

Medulloblastoma of children can be managed with combination of Radiotherapy and chemotherapy Radiotherapy and chemotherapy have only a marginal effect on survival in cerebral metastases and malignant gliomas in adults,

Prognosis

Gliomas can rarely be completely excised. Prognosis is based on histological grade also. Oligodendrogliomas are often slow-growing and relatively benign in the early stages.