W1 - Intracranial Space Occupying Lesions (ISOLs) - condensed Flashcards
Define the term “space-occupying lesion”
SOL - A body of tissue or fluid that resides within a body structure and compresses or displaces normal tissue structures, commonly cause local signs and symptoms (but may be asymptomatic).
ISOL - SOLs found in the cranial cavity.
- Neoplastic
- Haematoma
- Granuloma
- Vascular aneurysm
Define the term “malignant” with respect to brain tumours
Brain tumours malignancy is normally defined solely by rate of growth, rather than metastatic ability.
Discuss the mechanisms by which intracranial tumours produce clinical symptoms and signs
Rapid growth rate causes:
- Invasion & replacement of CNS tissue
- Local compression & shifting of CNS structures
- Neoangiogenesis of tumour
- Obstruction of CSF flow
- CNS herniation
Discuss the headache which is characteristic of raised ICP caused by neoplasms
Early stage:
- Diffuse, mild HA
- Agg: Morning, lying
- Rel: Vertical postures, deep breathing
Intermediate stage:
- HA more severe & constant
- Agg: Coughing, bending, neck movement
Late stage:
- HA may wake pt
Discuss the general classification of the clinical manifestations produced by intracranial tumours. In each case, discuss the underlying mechanism(s) responsible for the production of signs & symptoms.
- Generalised Ssx
- Focal Ssx
- False-localising Ssx
List and discuss the major generalised symptoms and signs which accompany intracranial tumours
- HA
- Papilloedema
- Vomiting
- Mental changes
- Plateau waves
- Generalised seizures
List and discuss the major focal symptoms which accompany intracranial tumours of:
a) Frontal lobe
b) Parietal lobe
c) Temporal lobe
d) Occipital lobe
e) Brain stem
f) Cerebellum
g) Cranial nerves
a) Frontal lobe
- Often asymptomatic
- Personality changes
- Abnormal gait
- Urinary frequency
- Mono/hemiparesis (mild)
- Broca’s aphasia (dominant hemisphere)
b) Parietal lobe
- Cortical sensory abnormalities (contralateral half of body)
- Contralateral impairment of all sensory modalities (if thalamus involved)
If dominant side affected:
- Apraxia
If non-dominant side affected: -
- Anosognosia
- difficulty with visual-spatial orientation
c) Temporal lobe
- Seizures
- Hallucinations (common)
- Superior quadrantanopia
- Wernicke’s aphasia
d) Occipital lobe
- Contralateral visual field defects
- Contralateral visual seizures
e) Brain stem
- UMN or LMN Ssx that may affect any of the CNs
f) Cerebellum
- Early Ssx of raised ICP
- Gait ataxia
- Ipsilateral extremity ataxia
g) Revise CN lesion Ssx. Any CN may be affected.
Discuss endocrine conditions which are typically produced by tumours in the region of the:
a) Sella turcica
b) Pineal gland
a) Sella turcica
- Cause: Pituitary adenoma (common)
- Characteristics: Usually very small
Ssx:
- Amenorrhoea-galactorrhoea syndrome
- Acromegaly
- Cushing’s disease
Other adenomas may become large and compress the: Diaphragm sella, optic chiasm, oculomotor nerve
b) Pineal gland
- Cause: Usually embryonic growths (eg teratomas, germinomas), common in children
Ssx
- Hydrocephalus
- Loss of upward gaze or pupillary fixation gaze
- Deafness
List the intracranial tumours which commonly produce endocrine abnormalities
Lesions of the:
- Pituitary fossa
- Suprasellar cistern
- Pineal area
Define the term “leptomeninges”
The two inner meningeal layers (arachnoid and pia), between which circulates the CSF (subarachnoid space)
List the tumours which most commonly affect the leptomeninges
- Meningioma
- Lymphomas
- Leukaemia
- Breast cancer
- Lung cancer
- Malignant melanoma
What is a false localising symptom/sign? Discuss
A symptom/sign caused by compression/displacement of normal CNS tissue distant from tumour site, resulting from the displacement of CNS structures due to tumour growth
