Subarrachnoid haemorrhage Flashcards

1
Q

What is xanthochromia?

A

Yellowish appearance of cerebrospinal fluid that occurs several hours after bleeding into the subarachnoid space caused by certain medical conditions, most commonly subarachnoid hemorrhage. Blood breakdown products.

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2
Q

What are vascular causes of a thunderclap headache?

A
  • SAH
  • Venous sinus thrombosis
  • Arterial dissection
  • Stroke
  • ICH
  • Vasculitis
  • Reversible cerebrovascular vasoconstriciton syndrome
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3
Q

What are non-vascular causes of thunderclap headache?

A
  • Spontaneous intracranial hypotension
  • Hypertensive encephalopathy
  • Meningitis
  • SOL
  • Pituitary apoplexy
  • Sinusitis
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4
Q

What is the definition of thunderclap headache?

A

It is defined as a severe headache/worst ever that takes seconds to minutes to reach maximum intensity (1-5 minutes)

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5
Q

What primary headache disorders would you consider if someone presented with thunderclap headache?

A
  • Primary cough
  • Coital
  • Exertional headache
  • Primary thunderclap headache
  • Migraine
  • Cluster headaches
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6
Q

What investigations would you do in someone with thunderclap headache?

A
  • Bloods - U+E, LFTs, FBC, Coag, CRP, BC if pyrexial
  • ECG
  • Urgent CT angio brain - DSA
  • Consider LP after 12 hours - if CT negative but strong clinical suspicion
  • Consider MRI - AVM malformation better viewed
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7
Q

What would you be looking for on LP in someone presenting with thunderclap headache?

A
  • Xanthochromia
  • Opening Pressure and constituents (raised pressure)

Wcc in meningitis

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8
Q

What is a subarachnoid haemorrhage?

A

Spontaneous arterial bleeding into the subarachnoid space, and is usually clearly recognizable clinically from its dramatic onset

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9
Q

What age range does subarachnoid haemorrhage?

A

35-65 (rare below 20)

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10
Q

What are causes of a subarachnoid haemorrhage?

A
  • Saccular (berry) aneurysm (80%)
  • AVM (15%)
  • Other rare causes (5%) - bleeding disorders, cavernous haemoangiomas, traumatic SAH, neoplasm, cortical thrombosis, encephalitis
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11
Q

What are common sites for berry aneurysms to occur?

A

Junctions of:

  • PCA and internal carotid
  • ACA and anterior cerebral artery
  • Bifurcation of MCA
  • Others - basilar, posterior inferior cerebellar, Intracavernous internal carotid
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12
Q

How do berry aneurysms cause symptoms?

A

Either by rupture or compression on surrounding structures

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13
Q

What are arteriovenous malformations?

A

Vascular developmental malformations, often with a fistula between arterial and venous systems causing high flow through the AVM and high pressure arterialization of draining veins

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14
Q

What is the risk (%) of first haemorrhage in someone with an AVM?

A

2-3% per year

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15
Q

What is the risk of rebleed in someone with AVM?

A

10% per year

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16
Q

What is the following?

A

Subarachnoid haemorrhage

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17
Q

What are features of subarachnoid haemorrhage on CT?

A

Hyperattenuating material is seen filling the subarachnoid space. Most commonly this is apparent around the circle of Willis, on account of the majority of berry aneurysms occurring in this region (~65%), or in the Sylvian fissure (~30%)

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18
Q

What are symptoms of a subarachnoid haemorrhage?

A
  • Sudden onset excruciating headache (thunderclap) - typically occipital
  • Other features of Meningism - Neck stiffness, photophobia, nausea/vomiting
  • Collapse and loss of consciousness (50%)
  • Seizures
  • Drowsiness - may last for days
  • Coma
  • Focal neurology may suggest site eg pupil changes suggesting CN 3 palsy with posterior communicating artery aneurysm (but could also be increased ICP!),
    6the nerve palsy could be flase localising due to hydrocephalus
19
Q

What can preceed a thunderclap headache caused by SAH?

A

Sentinal headache - indicative of small bleed before big from offending aneurysm

20
Q

What are signs of SAH?

A
  • Neck stiffness
  • Kernig’s sign - typically at least 6 hrs after
  • CNIII nerve palsy
  • Retinal, subhyaloid and vitrous haemorrhage - tracking below retinal hyaloid membrane
  • Papilloedema
  • Focal neurology indicating site
21
Q

A berry aneurysm in which location can cause a CNIII palsy?

A

Posterior communicating artery (PCOM) - sits next to CNIII

22
Q

If someone presented with symptoms of a sudden headache and features of meningism, what two main diagnoses would you want to rule out?

A
  • Subarachnoid haemorrhage
  • Meningitis
23
Q

Why does subarachnoid haemorrhage cause meningism?

A

Blood irritates the meninges, leading to inflammation

24
Q

Investigations subarachnoid haemorrhage

A

CT scan (detects >90% within first 48 hours)

Lumbar puncutre if CT neg

Cerebral angiography

Blood tests: Us and Es, haematology (Hb, WBC and clotting)

25
Q

When is LP most sensitive for xanthochromia?

A

12 hours post haemorrhage

26
Q

What are risk factors for SAH?

A
  • Previous SAH
  • Smoking
  • Alcohol
  • HTN
  • Bleeding Disorders
  • Family History
  • Polycystic kidneys
  • Coarctation of Aorta
  • Ehlers Danlos syndrome
27
Q

What would your differential diangosis be for sudden onset headache?

A
  • SAH
  • Meningitis
  • Migraine
  • Intracerebral bleed
  • Cortical vein thrombosis
  • Carotid/vetebral artery dissection
  • Benign thunderclap headache
28
Q

Why would you perform U+E’s in someone with thunderclap headache?

A

Look for hyponatraemia + hypovolaemia from SAIDH or cerebral salt wasting -> worsens vasopasm

29
Q

Why might you do Coag screen and LFTs in someone with thuinderclap headache?

A

Look for signs of bleeding disorders which could cause SAH

30
Q

How would you manage a SAH?

A

Refer to neurosurgery immediately

  • ABCDE
  • Continuous neuro exam
  • Fluids - keep well hydrated
  • If seizures - anticonvulsants
  • Analgesia
  • Nimodipine - reduces vasospasm (calcium channel blocker)
  • Surgery

Triple H therapy = hypertension, hypervolaemia and hyperdilution (antihypertensives should be avoided because they increase ischaemic complications)

31
Q

What surgical interventions are available for SAH repair?

A
  • Endovascular coiling (prerable to clipping)
  • Surgical clipping
32
Q

What is the more preferable surgical intervention for SAH?

A

Endovascular coiling

33
Q

What are complications of SAH?

A
  • Rebleeding - commonest cause of death
  • Cerebral ischaemia due to vasospasm - may cause permanent CNS defect
  • Obstructive hydrocephalus - due to blockage
  • Hyponatraemia - common but can be managed with fluid restriction
34
Q

What can occur after the initial haemorrhage that occurs in SAH?

A

Vasospasm causing ischaemia and secondary brain damage

35
Q

What proportion of those with SAH present with signs of TIA/Stroke?

A

25% - due to secondary vasospasm

36
Q

When is risk of cerebral oedema and vasospasm greatest following a SAH?

A

Between 72 hrs and 10 days

37
Q

What is the overal mortality rate of SAH?

A

35-50% - About 30% die within a few days, and another 10-15% within a few weeks.

1/6 will die before reaching hospital, 10% mortality rate in hospital.

38
Q

When does someone who has had a SAH have the best prognosis?

A

When no lesion is detected - worst prognosis for aneurysms

39
Q

Why might you do an ECG in someone with SAH?

A

50% of patients with SAH have an abnormal ECG on admission

  • Arrhythmias
  • Prolonged QTc
  • ST segment/T wave abnormalities.
40
Q

What is the most accurate method for visualising aneurysms?

A

Digital subtraction angiography

41
Q

When should an LP be performed in someone with SAH?

A

If CT is unrevieling - wait 12 hours for RBCs to start lysing

42
Q

Where does the bleed happen in a SAH?

A

Between pia and arachnoid matter

43
Q

What is associated wtih berry aneurysms

A

Polycystic kidneys

Co-arctation of aorta

Ehlers-danlos syndrome

44
Q

How can AV malformations present?

A

INTRACRANIAL HAEMORRHAGE

seizures

FN defecit

Headache

Impaired higher cortical function

Bruit