JC_WCS_002_BrainMass

JC M WCS 2: MASS IN BRAIN
Dr. Fan Yiu-wah

Neurosurgery

Tue 22-10-02
CLINICAL PRESENTATION

Local effect

Specific neurological deficit
Focal seizure
Mass effect
Cerebral oedema
Hydrocephalus - around Aqueduct/ 4^th ventricle

General effect

Herniation syndrome

Generalised seizure

 ICP

Generalised headache - worse in morning ( ICP - sleep apnoea - CO₂ retention - VD - aggravate ICP - stretch dura [Note: not "morning headache" - misnomer]

Nausea & vomiting - hyperventilation - blow off CO₂ - VC - ¯ ICP

Papilloedema

COMPARTMENTAL PROBLEMS

Uncal herniation

Uncus compress on brain stem
Impaired consciousness
Dilated ipsilateral pupil (ipsilat CN III) classic
Contralateral hemiplegia syndrome
Kernohan's notch with ipsilateral hemiplegia (contralat cerebral peduncle pushed across/ compressed) - pitfall in uncal herniation Dx

Cingular herniation

Displaced cingular gyrus
ACA may be compromised (ant cerebral a)
C/P non-specific

Central herniation

Bilat cerebral swelling (hepatic encephalopathy, metabolic prob)
Downward displacement of diencephalon (b/c supratentorial mass > posterior fossa) - BS compressed
Bilateral small pupils
Cheyne-Stokes respiration
Unconscious

Tonsillar herniation

Posterior fossa mass

Cerebellar tonsil through foramen magnum - compress medulla

Cardiorespiratory problems

Cheynes-Stokes respiration

Impaired consciousness

Decorticate/ decerebrate posture

Aggravated by cough/ manoeuvre that ICP

Eg. child with medulloblastoma (hydrcephalus + ICP)

INCIDENCE

	Adult	Children	Incidence	Type
Supratent	80-85%	40%	25%	Glioblastoma multiforme
Infrantent	15-20%	60%	20%	Meningioma Anaplastic astrocytoma
Eg.	Glial tissue Glioma Metastases Meningioma	Primitive neurones Medulloblastoma Cerebellar astrocytoma	5%	Astrocytoma Nerve sheath tumour Pituitary adenoma Mixed malignant glioma Others
			2.5%	Craniopharyngioma Medulloblastoma Ependymoma Oligodendroglioma

Others - Lymphoma, Hemangioblastoma, Chrodoma, Ganglioglioma, Neuroblastoma, Dermoid, Pineocytoma/ blastoma, Choroid plexus papilloma/ carcinoma

CLASSIFICATION

a) 1^o vs. 2^o

1^o - glia, neurone

2^o - more common, 25% ca Pt have brain secondaries

b) Intra vs. Extra-axial

Intra - originate within brain tissue, morbidity w/ resection - eg. Glioma

Extra - originate in dura/ arachnoid mater, n sheath, ¯ mortality - eg. Meningioma, schwannoma

c) Cell origin

Neuroepithelial tissue - astrocytoma, oligodendroglioma, ependymoma, pineal cell tumour, neuronal tumour, embryonal tumour, primitive neuroepithelial tumour (PNET)

Nerve sheath cells - neurilemmoma

Meninges - meningioma

Lymphoid cells - primary malignant lymphoma

Blood vessel - haemangioblastoma

Germ cell (around pineal) - geminoma, choriocarcinoma, teratoma, embryonal carcinoma

Malformative tumour - craniophargyngioma (nr pituitary), epidermoid/ dermoid cyst

Vascular malformation - capillary telangiectasia, cavernous angioma, AVM, venous malformation, Sturge-Weber disease

Anterior pituitary - pituitary adenoma (pituitary has no BBB \ more endo than CNS; different cell lines, each w/ specific syndrome - eg. Cushing, Acromegalic)

Local extension from regional tumours - glomus jugular tumour, olfactory neuroblastoma

Metastatic tumour

Unclassified

INVESTIGATION

CT scan

MRI

Angiogram

Skull X-ray - no longer used

Benign vs. Malignant

Benign - eg. meningioma (but can compress structures - ICP - kill Pt)

Malignant - eg. Glioblastoma multiform (rarely metastasise outside CNS)

\ Challenges definition of benign and malig

TREATMENT

Anticonvulsant

Supratentorial cortical lesions (tend to be (+) cf. with (-) infratentorial lesions)
Benign lesions (tend to irritate neurones - firing, cf. malignant neurones which damage cells)
Give prophylactic anticonvulsants for supratentorial lesion (esp. motor, speech area), never for cerebellar lesions

Steroid - Cerebral oedema

Surgery

Max removal within safety limit - "Resection margin" cannot have margins in brain (eg. squamous cell carc 1-2 cm; melanoma 5 cm margin)

Cytoreduction

Hydrocephalus

Posterior fossa lesion - obstruction
CSF metastasis - eg. leptomeningeal spread (ependymoma, medulloblastoma), may grow along saggital granulations

Radiation

Delivery (1) Tele-radiotherapy (external beam - fr distance) (2) Brachy-radiotherapy (interstitial implant - usu. at resection)
Fractionation (1) Fractionated (hyper, hypo - ca cells die more quickly, N cells recover) (2) Single dose - both ca and N cells die
Technique (1) Stereotactic - acute targeting technique (eg. gamma/ X-knife) (2) Conformal

Chemotherapy

¯ Use for brain tumour ( Px glioblastoma multiforme of 12m by 2m) - (1) BBB (2) S/E (3) Cost

Immunotherapy - products attaching ca through the immune system (eg. Monoclonal Ab, ca vaccines, Ab from tobacco plants, cox-2 inhibitors, etc.)

Gene therapy - transfer of nucleic acids (DNA, RNA) into target cells to correct/ disrupt path process (1) in vitro - genes into cells cultured outside of the body prior to placing those cells back into the body (2) in vivo - direct admin of gene(s) to reach a target cell in the body

BRAIN METASTASIS

Commonest intracranial tumour

Incidence + Life expectancy of cancer patients

25% ca Pt (esp. ca lung - pul circ - pul v - LH - systemic arterial - brain takes 20-25% CO)

Often symptomatic (or 1^o lesion asymptomatic, 2^o in brain symptomatic)

Site	%
Lung	44
Breast	10
Renal	7
Colon	6
Melanoma	3
Undetermined	10

\ Must check chest for 1^o

Radiological diagnosis

Differential diagnosis

Brain metastasis - central necrosis due to expansion, ring-enhancing lesion "doughnut sign"

Primary brain tumour

Brain abscess - ring-enhancing lesion, thin capsule

Treatment

Consider

Status of primary - control, histology (when Dx metastasis - 8% abscess - ie. Wrong Dx)

Extent of other systemic metastasis

K-score - Karnofsky Performance Status - standard way of measuring ability of ca Pt to perform ordinary tasks (range 0 to 100, score = ability for ADL, used: prognosis, D in functioning, Pt include in clinical trial?)

Response to radiotherapy and chemotherapy - if good, no pt doing surg

Number and location of brain lesions

Seizure control

Hydrocephalus

Cerebral oedema

Options (cannot cure metastases \ palliative)

Steroids - eg. Corticosteroid (Dexamethasone 10mg followed by 4mg qid) - GDU prophylaxis, imm-sup, DM, myopathy (\ not LT)

Craniotomy for brain metastasis

Whole-brain radiotherapy - eg. multiple metastases

Resection - solitary with press effect, histological Dx (5-11% are brain abscess + primary tumour), relieve symptoms, local cure

Stereotactic radiosurgery - not actual surgery (no incision), focal radiation (single/ high dose), refers to knife bet N and ca tissue, cannot replace surg in irritative/ freq seizure Pt

BRAIN ABSCESS

Features

Solitary / Multiple

¯ Incidence ( ENT = better Dx ME infection - through temporal bone - temporal/ cerebellar abscess

Radiological features (1) Cerebritis stage - hypodense with patchy enhancement (2) Mature abscess stage - ring enhancement

Pathogenesis

Direct inoculation
Spread from sinus infection - eg. frontal sinus - frontal; ME - temporal/ cerebellar
Hematogenous spread (1) Cutaneous (2) Endocarditis - mitral, atrial septal (3) Pulmonary infection - bronchiectasis, pyogenic (4) Paradoxical embolism - cutaneous, dental abscess

Note: cyanosis w/ focal neuro deficit - remember R-to-L shunt (1^o Dx = brain abscess)

Bacteriology (usu. mixed)

Anaerobes
Streptococci
Staphylococci
Enterobacteria

Haemophilus

Treatment

Medical - ABX ® cerebritis / multiple abscess

Surgical (1) Drain pus w/ catheter - 98% (2) Excise mature abscess capsule

NOTE

Paed drowsy, septic, cyanotic, heart disease, fever ® MUST do CT SCAN (exclude SOL) B4 LP to exclude meningitis