Causes of raised ICP?
Localised (Space Occupying) Lesions
- Haemorrhage or haematoma
- Tumour
- Abscess
Also Oedema post trauma
Types of herniation due to raised ICP?
Internal Shift or Herniation:
- Right-left e.g. subfalcine herniation (cingulate gyrus herniates under falx)
- Uncal Herniation (cerebrum moves down over tentorium)
- Coning (Cerebellum, mainly tonsils, moves into foramen magnum)
What happens to tissue around a tumour?
Ischaemia due to the squashing effect of the tumour
Early signs of a raising ICP?
Morning Headaches and vomiting from cortex/brainstem compression
Papilloedema & Visual Disturbance from pressure on optic nerve
What other signs appear as ICP increases?
- Pupillary Dilation from stretch on III
- 6th nerve palsy
- Focal Neurological Deficits
- Falling GCS from pressure on Cortex/brainstem
- Brain Stem Death from coning
Intracranial tumours can be divided into 3 major categories?
- Primary CNS tumours
- Secondary (Metastatic) CNS tumours
- Cells from outside CNS e.g. Meningioma
What are the classes of Primary tumours?
These Ones are CNS tumours and are malignant:
- Gliomas (many types based on specific glial cell)
- Medulloblastoma (Embryonic Neural Cells)
These are the ones originating outside the brain:
- Meningioma (Arachnoid)
- Schwannoma/Neurofibroma (nerve sheath(
- Adenoma (Pituitary)
- Lymphoma
- Haemanioblastoma (Capillaries)
What cancers commonly metastasise to the brain?
- Breast
- Lung
- Kidney
- Colon
- Melanoma
where anatomically in the brain would you find tumours?
Adults - Above Tentorium
Children - Mainly below Tentorium
Describe Gliomas?
Originate from Glial Cells e.g. Astrocytoma or Glioblastoma
They have no capsule so diffuse edges
They are malignant but do not metastasise outside the CNS
What cell do glioblastomas and astrocytomas originate from?
Both from Astrocytes
Whats the difference between a glioblastoma and an astrocytoma?
Both originate from astrocytes & are malignant
Astrocytomas:
- Bland mostly normal cells
- Low Grade tumour
- Grows very slowly
Glioblastoma:
- Cellularly Atypical (multiple or irregular nuclei)
- Grows very quickly
- Shows necrosis microscopically
What does a medulloblastoma originate from?
Primitive Neuroectoderm (primitive Neural cells)
Describe a medulloblastoma?
- Forms sheets of small undifferentiated cells
- Malignant
Where and in who do medulloblastomas appear?
- Mostly in children
- In Posterior Fossa especially around the brainstem
Describe the growth of a meningioma?
Originates in arachnocytes
They’re benign so no metastases but may invade skull or crush brain
Grows slowly making it often resectable
how does a meningioma appear microscopically?
Bland cells in small groups +/- calcification
They tend to resemble a normal arachnoid granulation
What do we call the calcifications of a meningioma?
Psammoma body formation
Give one major example of a schwannoma?
VIII nerve Schwannoma (Acoustic Neuroma)
Generally at angle of Pons & Cerebellum
What are the consequences of an Acoustic
Neuroma?
- Unilateral Deafness
- Benign lesion very difficult to remove
Can also put pressure on facial nerve
What does a pituitary adenoma do?
- Impinge on optic chiasm
- Pituitary hormone secretion
What makes up a CNS lymphoma?
Diffuse Large B-cell lymphoma
Consequences of haemangioblastoma?
Space occupying and may bleed
What makes up most secondary tumours in the brain?
Carcinomas
Clinical Presentation of Intracranial Tumours?
- Symptoms/signs of raised ICP
- Focal Neurological Deficits
- Seizures (in lesions of cerebral cortex, think tumour in an adult onset seizure)
- CSF obstruction (Hydrocephalus)
How would we investigate a suspected Intracranial Tumour?
- History/exam
- CT/MRI
- PET scan
- Biopsy
- Check for sources of secondary tumour e.g. CXR/AXR/PXR
What are the goals of Intracranial tumour management?
- Diagnosis of benign vs malignant
- Improve quality of life (reducing symptoms and neurological deficits)
- Prolonging life expectancy
What treatments are available for Intracranial Tumours?
- Chemo/radiotherapy
- Corticosteroids (reduces ICP from oedema)
- Anti-epileptics to prevent seizures
- Analgesia
- Anti-emetics
Surgery
- Either as complete resection
- Or debulking to reduce symptoms/ICP
Whats the prognosis for meningioma?
Usually surgically resectable
May need anticonvulsants
Prognosis for Gliomas?
Astrocytomas have a long life expectancy
Glioblastoma Multiformes have a 1yr survival avg.
