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Neurosurgery BRAIN ABSCESS * Aetiology: A) Predisposing factors & routes of infections: 1. Local spread of infection from: a- Otitis media and mastoiditis accounts for 50% of cases > cerebellar and temporal lobe abscess . b - Frontal , ethmoid sinusitis & dental infection —> frontal abscess. 2. Direct implantation of the organisms through a penetrating trauma = single brain abscess. 3. Blood spread as a complication of lung abscess or bacteremia — multiple deeply seated brain abscesses . B) Organisms: Staph., strept. and pneumococci are common. Semicircular canals Vestibulo- cochlear Pinna i : ; nerve Eustachian tube Malleus = Bip canner aN Incus ADAM. Page 1 [Type text] Neurosurgery * Pathology: There are 3 stages: 1. Septic encephalitis with diffuse oedema and swelling of the affected part. 2. Localization to form acute abscess with thin glial wall (usually after 3 weeks). 3. Chronicity with pus within a thick glial wall (after 6 weeks). * Clinical picture: 1. Initially there are no specific symptoms & signs which usually delay the diagnosis for few days . 2. Manifestations of increased intracranial tension. Progressive severe headache resistant to analgesics is the commonest symptom . 3. General manifestations of toxaemia and low grade fever in 50% of cases. Page 2 [Type text] Neurosurgery Intracranial tumors * This term include metastases and tumors arising from skull , meninges , brain tissues , cranial nerves , pituitary & pineal glands , blood vessels and congenital remainants . * Pathology: brain tumours may be: 1. Metastasis: Usually from carcinoma of lung, breast, prostate or kidney. It is the commonest intracranial neoplasm. 2. Gleal tumours: (Gliomas). These are malignant tumours arising from glial tissue. Gliomas include astrocytoma (which is the commonest iry malignant brain tumor in adults ), oligodendroglioma , ependymoma and glioblastoma . 3. Meningioma: It arises from the arachnoid matter & is benign. 4. Acoustic Neuroma: A benign tumour in 8th. cranial nerve. 5. Pituitary tumours. 6. Embryonic tumor : Medulloblastoma is the commonest iry malignant brain tumor in children ( appears in first decade ) 7.Rarely congenital tumours (craniopharyngioma or dermoids) 8. Vascular tumours (haemangioma or haemangioblastoma). * The commonest spinal cord tumor is ependymomas(40-60% ).It arises from ependymal cells that line the passage of the CSF . * Schwannoma ( neurilemmoma ) is the commonest peripheral nerve tumor . It arises from Schwnn’s cell which form myelin sheath . It is painful and tender . * Clinical picture: 1. Impairment of cerebral functions as amnesia , irritability and confusion . 2. Manifestations of increased intracrantal tension : Page 4 [Type text] Neurosurgery eHeadache is present in 1/3 of cases and is of variable nature and site according to the site of the tumor . It is due to increase ICT or to stretch of the meninges . eVomiting is not preceded by nausea , projectile , not related to meals and occurs in early morning . eBlurring of vision early due to papilloedema and later optic atrophy . ¢ Papilloedema is the most significant sign of increase ICT . s of Raised ICP Papilledema * Normal Papilledema 3. Focal manifestations depend on the site of the tumor as hemiplegia in tumor of motor area or aphasia in tumor of speech area . 4. Epileptic fits: The earliest manifestations due to local irritation of the neurones. * Investigations: 1-Plain X-ray of the skull: May reveal: a - Increase intracranial tension: Separation of sutures (before their closure), silver beaten appearance or finger prints (after closure of sutures) or erosion of the clinoid process with saucerization of the sella turcica in supracellar tumours. Page 5 [Type text] Neurosurgery Intracranial Tumor Posterior clincid = Dorsum sellae “ballooning sella” fy, a Pituitary tumor Page 7 [Type text] Neurosurgery * Treatment: I. Surgical treatment : ( main line of treatment) e If the patient show signs of brain compression ( commonest cause of death in neurosurgical patient ) , urgent IV dehydration ( 25% dextrose or manitol) with dexamesathone ( treat oedem surrounding the tumor ) . e If the condition is associated with hydrocephalus , it is dealt with first by ventriculo-peritoneal shunt . e Open Surgical excision of intra-cranial tumor through: 1- Frontal osteoplastic flap for tumors of anterior cranial fossa . 2- Temporal osteoplastic flap for tumors of the middle cranial fossa. 3-Suboccipital cramotomy for posterior cranial fossa or cerebellar tumours . e Recent neurosurgical methods in treatment of intra- cranial tumors : 1.C.T. or MRI guided stereotactic surgery : = Indication : Biopsy or excision of deeply seated brain tumor = Method : A head frame is used to facilitate very accurate 3 dimensional localization of the tumor which can be reached by fine instruments introduced through a small burr hole . 2. Microsurgical excision of the tumor. 3. Neuroscopy (for intraventricular tumors) are available. II. MRI-guided laser ablation of the tumor is an alternative for surgery in deep inaccessible dangerous tumors . III. MRI-guided radiotherapy . IV. Chemotherapy. Page 8 [Type text] Neurosurgery Pituitary Tumors Il _Postencr obe * Pathology & clinical picture : Pituitary tumors are classified according to : TI) Functioning or non-functioning : A) Non functioning pituitary adenomas (chromophobe adenoma) ( 30% ) e In early cases , these tumors are usually symptomless . e When they are large , they compress optic chiasma —> visual field defect ( bitemporal hemianopia ) , optic atrophy & signs of increased intracranial tension. eCompression of the gland > hypopituitrism. Optic chiasm Pituitary gland Internal carotid artery Oculomotor nerve Trochlear nerve Abducens nerve Mi Cavernous sinus Ve Sphenoid sinus Page 10 [Type text] Neurosurgery B ) Functioning pituitary adenomas : ( 70% ) 1.Prolactinomas: ( The commonest , 40% ) e They cause amenorrhoea, galactorrhoea , infertility in females & impotence in males . 2. Acidophil adenoma: Secrete growth hormone > gigantism or acromegaly. 3. Basophil adenoma: Very small, secrete ACTH > Cushing's syndrome. 4. Glyoprotein secreting adenomas that produce TSH, LH or FSH. 5. Adenomas secreting more than one hormone. II) According to size of the tumor into microadenomas ( less than 1 cm ) or macroadenomas ( more than 1 cm ) * Clinical features: 1. Endocranial symptoms usually appear first. 2. Pressure symptom: Absent in basophil adenomas, slight in acidophil adenomas . * Investigations : Hormonal assessment +other investigations for intra-cranial tumors . * Treatment: 1- Bromocreptine ( parlodel ) is anti-prolactine drug replace surgery for prolactinomas . 2- MRI-guided laser ablation of the tumor is an alternative for surgery . 3- MRI-guided radiotherapy . 4. Surgical: Endoscopic removal of the tumor through trans- sphenoidal approach ( sublabial or transnasal ). Page 11 [Type text] 
