Neurology

What is a subarachnoid haemorrhage?

Intracranial haemorrhage within subarachnoid space

What is the most common cause of subarachnoid haemorrhage?

Head injury - this is called traumatic SAH

What is the term for SAH in absence of trauma?

Spontaneous SAH

What are the causes of spontaneous SAH?

Intracranial aneurysm - saccular ‘berry’ aneurysms

Arteriovenous malformation

Pituitary apoplexy

Mycotic (infective) aneurysms

What conditions are associated with berry aneurysms?

Hypertension
Adult polycystic kidney disease

Ehlers-Danlos

How does a SAH haemorrhage present?

Headache - sudden-onset, ‘thunderclap’, severe, occipital, peaking in intensity within 5 minutes, may be a history of less-severe headaches the weeks prior

Nausea and vomiting

Meningism (photophobia, neck stiffness)

Coma'

Seizures

ECG changes including ST elevation may be seen → secondary to either ANS neural stimulation from hypothalamus OR increased catecholamines

What is the first-line choice for SAH investigation?

Non-contrast CT head

Acute blood (hyperdense/bright) is distributed in basal cisterns, sulci, and in severe cases ventricular system

What if CT for SAH is done in 6 hours of symptoms and appears normal?

Consider alternate diagnosis

Do not do lumbar puncture

What if CT for SAH is done more than 6 hours after symptoms and appears normal?

Persist with investigation

Do a lumbar puncture - 12 hours after onset of symptoms

^gives xanthochromia (from RBC breakdown) chance to develop

What is xanthochromia?

RBCs in CSF undergoing haemolysis: haemoglobin → oxyhaemoglobin → bilirubin

What other than xanthochromia can be seen on an SAH lumbar puncture?

Normal or raised opening pressure

What is the next step after SAH has been positively identified?

Investigate cause of pathology

CT intracranial angiogram - identify vascular lesion e.g. aneurysm or AVM

^ + / - digital subtraction angiogram (catheter angiogram)

What is the management of a confirmed subarachnoid haemorrhage?

Supportive - bed rest, analgesia, venous thromboembolism prophylaxis, discontinuation of antithrombotics (reversal of anticoagulation)

Vasospasm is prevented using a course of oral nimodipine

Intracranial aneurysms are at risk of rebleeding; most treated with coil by neuroradiologist; some need craniotomy and clipping by neurosurgeon

Nimodipine - MOA, uses, administration, adverse effects?

Dihydropyridine Ca2+-channel blocker; blocks L-type channels in vascular smooth muscle; dilation in cerebral blood vessels

Reduce risk of delayed cerebral ischaemia and improve neurological outcomes of SAH

Oral or via NG tube; 60mg every 4 hours for 21 days; DO NOT GIVE IV

Hypotension, headache, flushing, dizziness, nausea / GI upset, tachycardia / palpitations, peripheral oedema

What are the complications of aneurysmal SAH?

Re-bleeding - 10% cases, most common in first 12h; repeat CT should be arranged

Hydrocephalus - treat with ventricular drain; can be treated more long-term with ventriculoperitoneal shunt

Vasospasm - “cerebral ischaemia”; 7-14 days after onset; ensure euvolemia (normal blood volume); consider treatment with vasopressor if symptoms persist

Hyponatraemia - most typically due to syndrome inappropriate anti-diuretic hormone (SIADH)

Seizures

When would you give benzodiazepines in a seizure?

If the seizure is prolonged

Repeat after 10-15mins if necessary

What benzo is used for prolonged seizures?

Rectal diazepam

Diazepam - MOA, uses, administration, adverse effects?

Benzodiazepine; binds GABA-A receptor, enhances action of GABA (inhibitory in CNS), decreased neuronal excitability, anxiolytic / sedative / anticonvulsant / muscle-relaxant

Acute severe anxiety; acute seizures / status epilepticus; alcohol withdrawal (prevention/treatment of withdrawal seizures); muscle spasms / spasticity; procedural sedation / premedication

Oral, IV (some seizures), rectal (some seizures); give for short-period due to tolerance and dependence

Drowsiness and sedation; confusion; ataxia and impaired coordination; respiratory depression; tolerance and dependence; paradoxical agitation/aggression; dangerous with alcohol or opioids (CNS / respiratory depression)

What is the dosing for rectal diazepam in seizures?

When is thrombectomy and thrombolysis recommended to an ischaemic stroke patient?

CT evidence within 6 hours of symptom onset

An extended window of 6-24h can be allowed if CT perfusion or diffusion weighted MRI sequences show limited infarct core volume

(if a patient wakes up at 6:00 with symptoms then it is assumed to have started at 23:00 when they went to sleep)

Why would atorvastatin be given to an ischaemic stroke patient?

Secondary prevention, but is not immediate management

How is blood pressure managed in acute ischaemic stroke?

Should not be lowered in the acute phase unless complications (hypertensive encephalopathy or being considered for thrombolysis)

Control should be considered if they present within 6h and pressure >150mmHg

As well as atorvastatin (Which is only used for secondary prevention) what medication MUST be given in acute ischaemic stroke?

Aspirin 300mg orally or rectally

[Only if haemorrhagic stroke is excluded]

When should anticoagulants be restarted in an AF patient after ischaemic stroke?

When brain imaging has excluded haemorrhage

AND

Not until 14 days have passed from onset of stroke

What if a stroke patient has >3.5mmol/l cholesterol?

Must be immediately started on a statin

Many will delay treatment until at least 48h due to risk of haemorrhagic transformation

What is the modified Rankin scale?

Assesses degree of disability or dependence following a stroke

What is the National Institutes of Health Stroke Scale?

Severity caused by stroke

What is the scale requirements of thrombectomy for a stroke patient?

Rankin < 3

NIHSS > 5

What is the window for thrombectomy in a proximal anterior circulation in a stroke patient confirmed with CTA or MRA?

Within 6h of symptoms

Combine this with IV thrombolysis (if within 4.5h)

If a stroke patient is past the 6h window of thrombectomy, what is the criteria to still get thrombectomy?

CT perfusion or diffusion-weighted MRI sequences show limited infarct core volume

What is the window for potential thrombectomy with IV thrombolysis (if within 4.5h) for patients with proximal posterior circulation infarct?

Can be up to 24h window

This is so long as CT perfusion or diffusion-weighted MRI sequences show limited infarct volume

What does proximal posterior circulation of brain refer to?

Basilar or PCA

What blood thinner is recommended as secondary prevention AFTER an ischaemic stroke?

Clopidogrel

Aspirin only recommended after an ischaemic stroke if clopidogrel is contraindicated

When is carotid endarterectomy recommended?

If patient has suffered stroke or TIA in carotid territory and is not severely disabled

Should be considered if stenosis > 50%

It is completed after incident of ischaemic stroke and is secondary prevention to prevent further stroke

^this is ipsilateral carotid-territory TIA, non-disabling ischaemic stroke, retinal ischaemia

Should be performed within 14 days of symptom onset

What actually is carotid endarterectomy?

Removal of atherosclerotic plaque in carotid artery

Plaque often at bifurcation or proximal internal carotid

What nerves are at risk of damage in carotid endarterectomy?

Hypoglossal - tongue deviates to injured side

Vagus (particularly recurrent laryngeal) - hoarseness or vocal cord paralysis

Marginal mandibular branch of facial nerve - weakness of lower lip