Brain Tumours and Hydrocephalus Flashcards
Commonest Intracranial Tumours
Primary Intracranial Tumours account for 10% of
Neoplasms; Metastases (from Bronchus, Breast, Stomach,
Prostate, Thyroid, Kidney) are the commonest intracranial
tumours
Gliomas
Spread by direct extension and does not metastasise outside of the CNS
Malignant Tumour of Neuroepithelial origin; Usually found in the Hemispheres, but also in the Cerebellum, Brainstem and Spinal Cord; Associated with
Neurofibromatosis
Astrocytomas
Arise from Astrocytes; Grade I – IV; Grade IV Tumours are also known as Glioblastoma Multiforme (GBM), and can cause death in several months
▪ Cystic Astrocytomas of Childhood are relative Benign and usually Cerebellar
Oligodendrogliomas
Arise from Oligodendrocytes;
Grows slowly; Calcification is common
Meningiomas
Benign tumours arising from the Arachnoid Mater; May erode skull or cause local
Hyperostosis if near bone; Often occur along Intracranial Venous Sinuses into which they made invade; Unusual below the Tentorium
▪ Common sites include Parasagittal, Sphenoidal Ridge, Subfrontal Region,
Pituitary Fossa and Skull Base
Neurofibromas
Neurofibromas (Schwannomas) – Benign tumours from Schwann cells; Principally in Cerebellopontine
Angle arising from the Vestibulocochlear Sheath
▪ May be bilateral in Neurofibromatosis (NF2)
Other brain neoplasms
• Other Neoplasms include Cerebellar Haemangioblastoma
(Endothelium, Pericytes, Stromal cells), Ependymomas of the Fourth Ventricle (Associated with NF2), Pinealomas, Chordomas of the Skull Base, Glomus Tumours of the Jugular
Bulb, Medulloblastomas, Craniopharyngiomas and Primary CNS Lymphomas
Presentation of Brain Tumours: Mass Lesions
Mass lesions present either due to Direct Effect (Infiltration and Local Function impaired), Secondary Effects due to
Raised ICP/Shift (e.g. Papilloedema, Vomiting, Headache) or Provoking Generalised/Partial Seizures
o Cerebellar Neoplasms are the commonest Mass
Lesions in the UK;
What other causes can produce similar presentation?
Cerebral Abscesses, Tuberculomas,
Neurocysticercosis (Pork Tapeworm Infestation), SDH
and ICH may produce similar presentations
Presentation of Left Frontal Meningioma
Frontal Lobe Syndrome
over several years; Personality changes, Apathy,
Impaired Intellect; Development of Expressive Aphasia (Broca’s), Progressive Right
Hemiparesis; Pressure Headaches and Papilloedema
Presentation of Right Parietal Glioma
Left Inferior Homonymous Quadrantanopia (Baum’s), Left Limb Cortical Sensory Loss and Hemiparesis; Partial Seizures on the Left can develop
Presentation of Left Acoustic Schwannoma
Progressive Deafness of Left Ear, Left Facial Numbness
and Weakness, Cerebellar Ataxia on same side
Signs of Raised ICP
Pressure Headache, Vomiting, Papilloedema; Unusual; More indicative of Obstructive Hydrocephalus (e.g. Posterior Fossa mass obstructing CSF flow)
Signs of shifts in intracranial mass
Shifts in the Intracranial Mass causes distortion of the Upper Brainstem – Midline structures displaced causing Impaired Consciousness leading to Coning and Death; False Localising signs;
o Abducens Palsy – First on the side of the mass then bilaterally either due to
compression or stretching of the nerve
o Oculomotor palsy – Occurs in Uncal Herniation causing compression of nerve against
Petroclinoid Ligament; Ipsilateral Pupil Dilation; Parasympathetic compression before
Ophthalmoplegia (Surgical Third Nerve Palsy)
o Hemiparesis – Contralateral Cerebral Peduncle against the Tentorium produces
Ipsilateral Hemiparesis (Kernohan’s Notch)
How do seizures present in a brain tumour?
Common presenting feature in Malignant Brain Tumours; Partial Seizures (Simple/Complex) that evolve into GTCS are characteristic of Hemispheric Tumours; Pattern of Partial Seizure can help localise lesions
Management of Brain Tumours: Investigations
• CT/MRI; MRI is superior for Posterior Fossa Lesions; MRA and MR Spectroscopy for patterns of certain Gliomas; PET useful to locate Occult Primary Tumour with Brain Metastases
• CXR and other investigations for likely Extracranial Primary Tumour
• LP is contraindicated if possibility of Mass Lesion; Mostly unhelpful
Stereotactic Biopsy – Skull Burr-hole to ascertain Histology; Benign tumours are usually managed by Craniotomy and removal during exploration
How is cerebral oedema managed?
Cerebral Oedema treated with IV/Oral Dexamethasone; Epilepsy treated with Anticonvulsants
What is the most ideal treatment?
• Complete Surgical Removal is ideal in most cases, but not always possible/necessary
o Follow-up with Serial Imaging for Low-grade Gliomas
o Biopsy and Debulking for malignant tumours that may not be entirely removed
o Tumour removal required for Posterior Fossa tumours due to raised ICP and danger
of coning; Posterior Fossa exploration has 10% mortality
When can radiotherapy be used?
Usually given for Gliomas and Metastases; Solitary Metastases may be
excised; Chemotherapy of little value of majority of tumours
o Vincristine, Procarbazine, Temozolomide can be used
o Most Malignant Gliomas have poor prognosis e.g. GBM has <50% Survival at 2yrs
o Surgical Debulking and Radiotherapy improves survival by 4-5 months
• Stereotactic Radiotherapy (Gamma Knife or LINAC) – Collimated Radiotherapy beam to deliver high doses of radiation to small targets (<3cm ø)
o Small Metastases, Inaccessible Skull Base tumours; Also used for AVMs
What is hydrocephalus?
Excessive Accumulation of CSF within the head; Can be caused by disturbance of Formation, Flow or Absorption; High ICP and Ventricular Dilatation results
Infantile Hydrocephalus: Causes
o Arnold-Chiari Malformation – Cerebellar Tonsils
descend into the Cervical Canal leading to
Obstruction; Associated Spinal Bifida is common;
Syringomyelia
o Aqueduct Stenosis – Genetic or Acquired (e.g.
Neonatal Meningitis, Haemorrhage)
o Dandy-Walker Syndrome – Cerebellar Hypoplasia
and Fourth Ventricle Obstruction
Adult Hydrocephalus
Might be incidental finding; Could be stabilised from Childhood (Arrested Hydrocephalus) but can
still decompensate
o Presents as Headache, Cognitive Impairment, Raised
ICP, Ataxia depending on ICP severity and rate
o Elderly patients may have more gradual onset
o Caused by Posterior Fossa/Brainstem Tumours
(Fourth Ventricle Outflow), SAH, Head Injury,
Meningitis (E.g. TB), Third Ventricular Colloid Cyst
(Might present intermittently with Recurrent Headaches and LL Weakness), Choroid Plexus Papilloma secreting CSF (Rare)
Treatment of Hydrocephalus
Emergency Treatment by Decompression and Shunting (e.g. Ventriculoperitoneal = VP); Endoscopic Third Ventriculostomy (ETV) for suitable lesions
Normal Pressure Hydrocephalus
- Syndrome of Enlarged Lateral Ventricles in Elderly patients with Gait Apraxia (“Wobbly”), Dementia (“Wacky”), Urinary Incontinence (“Wet”)
- NPH is Low-grade Hydrocephalus with Intermittently Raised ICP
- VP Shunting may be required; Trial of LP over several days predicts response to Shunting
