subarachnoid haemorrhage

Question 1

What does subarachnoid hemorrhage (SAH) refer to?

Answer 1

Bleeding into the subarachnoid space

Question 2

What percentage of subarachnoid hemorrhage cases are nontraumatic or spontaneous?

Answer 2

5–10%

Question 3

What is the most common cause of nontraumatic subarachnoid hemorrhage?

Answer 3

Rupture of an aneurysm involving the circle of Willis

Question 4

What are common symptoms of nontraumatic SAH?

Answer 4

Sudden and severe headache, nausea, vomiting, signs of meningism, acute loss of consciousness

Question 5

What is the best initial diagnostic test for SAH?

Answer 5

Head CT without contrast

Question 6

How does acute subarachnoid bleeding appear on a head CT?

Answer 6

As hyperdensities in the subarachnoid space

Question 7

What additional tests may be necessary if clinical suspicion of SAH remains high after a negative CT?

Answer 7

Lumbar puncture or CT angiography

Question 8

What is always necessary once SAH is confirmed?

Answer 8

Angiography to identify the source of bleeding

Question 9

What are some potential sources of bleeding in SAH?

Answer 9

Aneurysms or other vascular abnormalities

Question 10

What does the management of SAH mostly consist of?

Answer 10

Neuroprotective measures, such as control of blood pressure

Question 11

What is indicated in aneurysmal SAH to prevent potentially fatal rebleeding?

Answer 11

Microsurgical clipping or endovascular coiling of the aneurysm

Question 12

What is a significant complication associated with aneurysmal SAH?

Answer 12

Rebleeding and delayed cerebral ischemia
high mortality rate

Question 13

What is the best initial test for suspected subarachnoid hemorrhage (SAH)?

Answer 13

Immediate head CT without contrast

Question 14

What is the follow-up procedure after confirming SAH?

Answer 14

Obtain angiography to confirm source of bleeding and plan treatment

Question 15

What should be done if the head CT is nondiagnostic but suspicion of SAH persists?

Answer 15

Perform second-line diagnostic tests: lumbar puncture or CTA

Question 16

In a neurologically intact patient, what does a nondiagnostic CT in the first 6 hours indicate?

Answer 16

SAH unlikely; consider other differential diagnoses

Question 17

What are the second-line tests for suspected SAH?

Answer 17

Lumbar puncture (LP) or CT angiography (CTA)

Question 18

What is the implication of a positive CT angiography (CTA)?

Answer 18

Consider if additional angiographic imaging is necessary (e.g., DSA, MRA) and plan intervention

Question 19

What does a negative CT angiography (CTA) suggest?

Answer 19

SAH can be ruled out; consider other diagnoses
If suspicion remains high (rare), additional imaging may be needed eg. DSA, MRA

Question 20

Ottawa SAH clinical decision rule

Answer 20

use to rule out SAH in selected patients presenting to the ED with acute headache
for alert patients with non traumatic headache reaching maximum intensity within 1 hour

Question 21

What is the defining feature of SAH on a CT scan?

Answer 21

Blood in subarachnoid space (hyperdense) with variable extension and location

Question 22

Where is aneurysmal SAH typically located?

Answer 22

In the basal cisterns
Most aneurysms are located in the circle of Willis and when they bleed, blood extends along the basal cisterns. Large volumes of blood may extend into the ventricles or parenchyma.

Question 23

What CSF color indicates early findings suggestive of SAH?

Answer 23

Pink to red blood-tinged discoloration
This discoloration is an early indicator of possible bleeding.

Question 24

What is xanthochromia in the context of cerebrospinal fluid (CSF)?

Answer 24

The presence of bilirubin in the CSF secondary to the breakdown of RBCs, resulting in yellow discoloration
Xanthochromia is a late finding in SAH.

Question 25

What is the RBC:WBC ratio in cerebrospinal fluid (CSF)?

Answer 25

similar to that in peripheral blood, there will be a normal RBC:WCC ratio useful for distinguishing SAH from meningitis

Question 26

What is the expected RBC count in CSF during an SAH evaluation?

Answer 26

Elevated (no specific threshold) WCC may be also be mildly elevated

Question 27

What is the expected glucose level in CSF for SAH?

Answer 27

Normal

Question 28

What is the expected protein level in CSF during an SAH evaluation?

Answer 28

Elevated

Question 29

mainstays of initial management

Answer 29

stabilisation - A-E assessment and secure the airway if needed prevent rebreeding and reverse bleeding diatheses neuroprotection consult neuro and interventional radiology admit to neurocritical care

Question 30

how do you reverse bleeding diatheses

Answer 30

Anticoagulant reversal IV antihypertensive agents if blood pressure is elevated. Target SBP < 160 mm Hg if suspected increased ICP: Consider permissible hypertension (e.g., MAP > 90 mm Hg) to maintain cerebral perfusion pressure and prevent cerebral hypoperfusion. ? art line analgesia and antiemetics as needed. Antifibrinolytic therapy eg. TXA: not routinely recommended; potentially useful for patients with an expected delay in aneurysm repair [18][43]

Question 31

neuroprotective measures to consider

Answer 31

Start ICP management (e.g., elevate head 30°, IV mannitol, short-term controlled hyperventilation). Treatment goals: Euvolemia Euglycemia Normothermia Eunatremia: Patients are at risk for cerebral salt wasting and SIADH. Consider neuroprotective seizure prophylaxis following an intracranial event.

Question 32

endovascular coiling is

Answer 32

insertion of catheter under fluoroscopic guidance and placement of metal coils in the aneurysm lumen to interrupt blood flow and induce thrombotic occlusion minimally invasive, good for patients who are poor surgical candidates

Question 33

microsurgical clipping is

Answer 33

craniotomy and exposure of the aneurysm mechanical occlusion of the neck of the aneurysm using titanium clips more invasive

Question 34

mainstays of further management of aneurysmal SAH

Answer 34

prevention of vasospasm and delayed cerebral ischaemia treatment of hydrocephalus detection of cardiopulmonary complications DVT prophylaxis: mechanical initially, pharmacological 24 hours after repair

Question 35

how to prevent vasospasm after SAH

Answer 35

administer oral nimodipine in all patients frequent neuro examinations CT head 24-48 hours following repair consider transcranial doppler scan, repeated angiography, monitoring of ICP and cerebral perfusion pressure, continuous EEG lower threshold to transfuse packed RBC as anaemia is common

Question 36

What percentage of patients with SAH experience vasospasm?

Answer 36

Approximately 30%

Question 37

What diagnostic tool can help identify vasospasm?

Answer 37

Transcranial doppler ultrasound study vasospasms cause a measurable increase in the velocity of blood flow

Question 38

What is the pathophysiological process leading to nonobstructive hydrocephalus?

Answer 38

Impaired CSF reabsorption from the arachnoid villi causes non obstructive hydrocephalus increases ICP decreases cerebral perfusion pressure causes ischaemia this can lead to ischaemic stroke

Question 39

What substances are released during vasospasm that contribute to ischemia?

Answer 39

Clotting factors and vasoactive substances causing diffuse vasospasm of cerebral vessels oxyhemoglobin is believed to be the substance responsible

Question 40

When does vasospasm typically occur after SAH?

Answer 40

Between 3–10 days after SAH

Question 41

risk of recurrent bleeding in SAH

Answer 41

Occurs in 4–14% of patients with SAH in the first 24 hours Risk of rebleeding is highest in the first 2–12 hours after SAH The cumulative risk of recurrent bleeding within the first six months is about 50%.

Question 42

two types of hydrocephalus following SAH

Answer 42

acute obstructive: occurring minutes to hours after chronic communicating: usually occurs weeks to months after due to impaired CSF resorption from arachnoid villi

Question 43

delayed cerebral ischameia

Answer 43

complication of aneurysmal subarachnoid haemorrhage defined as worsening neurological status that cannot be attributed to other causes 3 days to 2 weeks following SAH

Question 44

why do patients sometimes get seizures following SAH

Answer 44

blood acts as an irritant

Question 45

SIADH following SAH

Answer 45

cerebral salt wasting rare causes hypovolaemic hypotonic hyponatraemia treated with hypertonic saline and fludrocortisone