Brain Tumours and Hydrocephalus

Question 1

Commonest Intracranial Tumours

Answer 1

Primary Intracranial Tumours account for 10% of
Neoplasms; Metastases (from Bronchus, Breast, Stomach,
Prostate, Thyroid, Kidney) are the commonest intracranial
tumours

Question 2

Gliomas

Answer 2

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

Question 3

Astrocytomas

Answer 3

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

Question 4

Oligodendrogliomas

Answer 4

Arise from Oligodendrocytes;

Grows slowly; Calcification is common

Question 5

Meningiomas

Answer 5

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

Question 6

Neurofibromas

Answer 6

Neurofibromas (Schwannomas) – Benign tumours from Schwann cells; Principally in Cerebellopontine
Angle arising from the Vestibulocochlear Sheath
▪ May be bilateral in Neurofibromatosis (NF2)

Question 7

Other brain neoplasms

Answer 7

• 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

Question 8

Presentation of Brain Tumours: Mass Lesions

Answer 8

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;

Question 9

What other causes can produce similar presentation?

Answer 9

Cerebral Abscesses, Tuberculomas,
Neurocysticercosis (Pork Tapeworm Infestation), SDH
and ICH may produce similar presentations

Question 10

Presentation of Left Frontal Meningioma

Answer 10

Frontal Lobe Syndrome
over several years; Personality changes, Apathy,
Impaired Intellect; Development of Expressive Aphasia (Broca’s), Progressive Right
Hemiparesis; Pressure Headaches and Papilloedema

Question 11

Presentation of Right Parietal Glioma

Answer 11

Left Inferior Homonymous Quadrantanopia (Baum’s), Left Limb Cortical Sensory Loss and Hemiparesis; Partial Seizures on the Left can develop

Question 12

Presentation of Left Acoustic Schwannoma

Answer 12

Progressive Deafness of Left Ear, Left Facial Numbness

and Weakness, Cerebellar Ataxia on same side

Question 13

Signs of Raised ICP

Answer 13

Pressure Headache, Vomiting, Papilloedema; Unusual; More indicative of Obstructive Hydrocephalus (e.g. Posterior Fossa mass obstructing CSF flow)

Question 14

Signs of shifts in intracranial mass

Answer 14

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)

Question 15

How do seizures present in a brain tumour?

Answer 15

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

Question 16

Management of Brain Tumours: Investigations

Answer 16

• 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

Question 17

How is cerebral oedema managed?

Answer 17

Cerebral Oedema treated with IV/Oral Dexamethasone; Epilepsy treated with Anticonvulsants

Question 18

What is the most ideal treatment?

Answer 18

• 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

Question 19

When can radiotherapy be used?

Answer 19

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

Question 20

What is hydrocephalus?

Answer 20

Excessive Accumulation of CSF within the head; Can be caused by disturbance of Formation, Flow or Absorption; High ICP and Ventricular Dilatation results

Question 21

Infantile Hydrocephalus: Causes

Answer 21

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

Question 22

Adult Hydrocephalus

Answer 22

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)

Question 23

Treatment of Hydrocephalus

Answer 23

Emergency Treatment by Decompression and Shunting (e.g. Ventriculoperitoneal = VP); Endoscopic Third Ventriculostomy (ETV) for suitable lesions

Question 24

Normal Pressure Hydrocephalus

Answer 24

• 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