Raised ICP Flashcards
How is a raised ICP diagnosed?
Unequal pupils
What is the normal ICP in adults?
<15mmHg
What are the causes of a raised ICP?
- Primary/metastatic tumours
- Head injury
- Haemorrhage
- Infection (e.g. meningitis)
- Hydrocephalus
- Cerebral oedema
- Status epilepticus
What is this a presentation of?
Headache worsening on coughing and leaning forwards, vomiting, altered GCS, drowsy, irritable, coma, hypertension, bradycardia, history of trauma, fixed dilated pupil, peripheral visual field loss, papilloedema (late).
Raised ICP
Which cranial nerve palsies most commonly occur with a raised ICP?
CN VI and CN III
How is a raised ICP investigated?
- FBC, U&Es, LFTs, glucose, clotting, culture
- Toxicology screen
- CT head
What is the management for a raised ICP?
- A-E, intubate if GCS <8
- Correct hypotension, elevate head off bed
- Hyperventilate if intubated to cause cerebral vasoconstriction
- Osmotic agents (e.g. mannitol)
- Dexamethasone for oedema around tumours
- Hypertonic saline
- Prevent and treat seizures, control fever, maintenance fluids
- Neurosurgery if haematoma
How can the cingulate gyrus herniate?
Sub falci
What does an uncal herniation cause?
Ipsilateral CN III palsy - fixed dilated pupil, followed by contralateral hemiparesis
What does a cerebellar tonsil herniation cause?
Coning and Cushing’s reflex, ataxia, CN VI palsy, upgoing plantars.
What are the three common herniations in a raised ICP?
- Sub falci herniation of the cingulate gyrus
- Uncal herniation
- Cerebellar tonsil herniation
What are the absolute contraindications of a lumbar puncture?
- Presence of infected skin over needle entry site
- Unequal pressure between supratentorial and infratentorial compartments following CT findings - midline shift and posterior fossa mass
What are the relative contraindications of a lumbar puncture?
Increased ICP, coagulopathy, brain abscess.
