Name 5 causes of raised intracranial pressure.
- Neoplasms: primary or mets (esp. breast, lung, melanoma)
- Abscesses: sinusitis, OM, dental, mastoiditis, surgery
- Haemorrhage: stroke, hypertension, intracranial (subarachnoid haemorrhage, subdural or epidural haematoma)
- CSF hydrocephalus: blockage of CSF at the aqueduct of Sylvius (cerebral aqueduct) by oedema or blood
- Infection: encephalitis (e.g. HSV), meningitis (e.g. NM, SP)
- Others: MS, granuloma, herniation
Describe 5 complications of raised ICP.
- Respiratory depression: compression of respiratory centres
- Bradycardia: decreased sympathetic input to heart
- Decerebrate posture: extension of neck
- Death: cardio-respiratory arrest
- Altered consciousness: due to coning (herniation of cerebellar tonsils through foramen magnum)
Describe the clinical Sx of spinal cord compression (5 Sx).
- Initially localised back pain: exacerbated by movements, worsens when supine
- Radicular pain: tight band like constrictions over thorax/abdo, radiates down arms/legs
- Lhermitte's sign: when neck flexed
- Incontinence: urinary & faecal
- Motor symptoms: e.g. heavy legs
What causes hypercalcemia in bone metastases?
- Result of bone destruction!!
- Tumours cells secretions may stimuate osteoclast activity
Name 4 common viral causes of meningitis.
- HSV& EBV
Name 4 common viral causes of encephalitis.
- EBV & HSV (same as meningitis)
Name 3 non-infectious causes of meningeal irritation.
- Subarachnoid haemorrhage
- Chemical meningitis (intrathecal drugs/contaminants)
Explain the mechanism of headache, neck stiffness, photophobia and N&V in meningitis.
- Headache: raised ICP
- Neck stiffness: cervical muscle spasm
- Photophobia: oedema causes over-stimulation of retinal photoreceptors with electric impulses to optic n.
- N&V: afferent nerves to the vomiting centre arise from splanchinic and vagal n., vestulo-labyrithine receptor, cerebral cortex and the chemoreceptors trigger zone (which samples CSF)