Subarachnoid Haemorrhage Flashcards
What are symptoms of SAH?
Sudden onset severe (thunderclap) headache, typically occipital Vomiing Collaspe Seizures Coma/drowsiness
Preceding sentinel headache
What are signs of SAH?
Neck stiffness
Photophobia
Kernig’s sign - Severe stiffness of the hamstrings causes an inability to straighten the leg when the hip is flexed to 90 degrees
Retinal, subhyaloid and vitreous bleads (Terson’s syndrome)
Focal neurology at onset may suggest sit of aneurysm or intracerebral haematoma
ST elevation may be seen
What are causes of SAH? Locations?
Intracranial berry aneurysm rupture
Junction of posterior communicating artery with the ICA
Anterior communicating artery with ACA
Bifurcation of the MCA
Arterio-venoius malformations
Encephalitis
Pituitary apoplexy
Vasculitis
Tumour invading blood vessel
What are risk factors for SAH?
Previous aneurysmal SAH Smoking Alcohol misuse HTN Bleeding disorders Mycotic (infective aneurysms)
Polycystic kidneys
Coarctation of aorta
EDS
assocaited with Berry aneuryss
What are differentials for SAH?
Meningitis Migraine Intracerebral bleed Cortical vein thormbosis Carotid/vertebral artery dissection Benign thunderclap headache
What tests to confirm SAH?
Urgent CT - Acute blood (hyper dense/bright on CT) is typically distributed in basal cisterns, sulk and in severe cases, the ventricular system
Consider LP if CT is negative but history is suggestive:
>12h after symtpom onset to allow the development of xanthochromia (result of RBC breakdown)
- this is yellow due to bilirubin which distinguishes a true SAH from a traumatic tap
After spontaneous SAH confirmed, identify causative pathology
CT intracranial angiogram to identify vascular lesion - aneurysm or AVM
What is management in SAH?
Refer all proven SAH to neurosurgery immediately
Maintain cerebral perfusion by keeping well hydrated but SBP < 160
Nimodipine is a calcium channel antagonist that reduces vasospasm
Most aneurysms treated by endovascular oil by interventional radiologist
Some require surgical craniotomy and clipping
Patient kept on strict bed rest, well controlled pressure and avoid straining
Hydrocephalus is temporarily treated with an eternal ventricular drain (CSF diverted into a bag at the bedside) or a long term ventriculo-peritoneal shunt
What are complications of SAH?
Rebleeding
Cerebral ischaemia due to vasospasm may cause permanent CNS deficit
Hydrocephalus due to blockage of arachnoid granulations
Hyponatraemia due to SIADH
Seizures
Death
What are prognosis factors in SAH?
Conscious level on admission
Drowsiness
Age
Amount of blood visible on CT head
