Neuro Flashcards
What is a stroke (cerebrovascular accident)?
When the blood supply to part of the brain is cut off
What can cause a stroke?
Small vessel occlusion/ thrombosis in situ
Cardiac emboli, CNS bleeds e.g. aneurysm rupture
Subarachnoid haemorrhage
What are the modifiable risk factors for strokes?
High BP, smoking, diabetes, heart disease, peripheral vascular disease
What medical conditions act as risk factors for strokes?
Hypertension, carotid artery stenosis, vasculitis, hyper viscosity
What is the ischaemic pathology of a stroke?
Sustained occlusion of a cerebral artery leads to ischaemic necrosis of the territory of the brain supplied by the affected artery
What is the haemorrhagic pathology of a stroke?
Hypertension due to ruptured Charcot-Bouchard aneurysms
Haematoma forms which destroys the brain structure and causes a sudden rise in intracranial pressure
Which manifestations of a stroke point to a haemorrhagic cause?
Meningism, severe headache, coma
Which manifestations of a stroke point to an ischaemic cause?
Carotid bruit, AF, past TIA, IHD
How do cerebral infarcts present?
Visuo-spatial deficit, dysphasia, spasticity (UMN)
Contralateral sensory loss or hemiplegia
How do brainstem infarcts present?
Quadriplegia, disturbances of gaze and vision, locked-in syndrome (aware but can’t respond)
How do lacunar infarcts present?
5 syndromes: Ataxic hemiparesis, pure motor, pure sensory, sensorimotor, dysarthria
How are strokes diagnosed?
FAST, CT/ MRI for haematoma, ECG: AF, CXR: LV hypertrophy
How are strokes managed?
Ischaemia - thrombolysis with IV Altepase
Aspirin for 2 weeks, then clopidogerol
Haemorrhagic - control BP (beta blocker)
Surgery - Clot evacuation
How can strokes be primarily prevented?
Control risk factors - hypertension, diabetes mellitus, cardiac disease, quit smoking. Use lifelong anticoagulant in AF and prosthetic heart valves
How can strokes be secondarily prevented?
Lower BP and cholesterol
Anti-platelet agents after stroke
Anticoagulation after stroke from AF
What is a transient ischaemic attack?
An ischaemic (usually embolic) neurological event with symptoms lasting <24h (often much shorter)
What are the causes of TIAs?
Atherothromboembolism from the carotid, cardioembolism, hyper viscosity, vasculitis
Explain the ABCD2 score for strokes
Age: 60+ BP: 140/90mmHg + Clinical features: unilateral weakness (2 points), speech disturbance without weakness Duration: 60+ = 2 points, 10-50 = 1 Diabetes
What indicates a high risk of stroke?
ABCD2 score 4+
AF, more than one TIA in one week
What is amaurosis fugax?
Occurs when the retinal artery is occluded, causing unilateral progressive vision loss ‘like a curtain descending’
What is a differential diagnosis for a TIA?
Focal epilepsy
How are TIAs investigated?
FBC, CXR, ECG, Carotid Doppler with angiography r CT
How are TIAs managed?
Control CV risk factors; high BP (beta blocker), diabetes, smoking
Antiplatelet drugs - aspirin (immediate)/clopidogrel
Statins - simvastatin
What is a carotid endarterectomy?
Surgery to remove a build-up of plaque in the carotid artery
What is a subarachnoid haemorrhage?
A spontaneous, non-traumatic bleed into the subarachnoid space (from circle of Willis)
What is the most common cause of a subarachnoid haemorrhage?
Rupture of a berry aneurysm - result in extensive bleeding through the subarachnoid space
What are the risk factors for a subarachnoid haemorrhage?
Smoking/alcohol excess, raised BP, bleeding disorders, PKD, aortic coarctation
How do subarachnoid haemorrhages present?
Sudden severe headache, vomiting, neck stiffness, collapse, seizures, coma
What is a differential diagnosis of a subarachnoid haemorrhage?
Benign thunderclap headache
How are subarachnoid haemorrhages diagnosed?
Macroscopy - blood present within SA space, with abundant clots around circle of Willis
CT - urgent
How are subarachnoid haemorrhages managed?
Well hydrated - maintain cerebral perfusion
CCB - nimodipine, reduces vasospasm and consequent morbidity
SURGERY URGENT
What are cerebral contusions?
Bruises on the surface of the brain
When do cerebral contusions occur?
When the brain suddenly moves within the cranial cavity and is crushed against the skull
What is a subdural haemorrhage?
Bleeding from bridging veins between cortex and venous sinuses, resulting in accumulating haematoma
When are subdural haemorrhages common?
When patients have a small brain e.g. alcoholics, dementia
Between what layers do subdural haemorrhages occur?
The dura and the arachnoid
What causes a subdural haemorrhage?
Lowered intracranial pressure Minor trauma (up to 9 months previous) - Results from tearing of delicate bridging veins that traverse the subdural space to drain into the cerebral venous sinuses
How do subdural haemorrhages present?
Fluctuating levels of consciousness, insidious physical/ intellectual slowing, sleepiness, headache, personality change
Why is there raised intracranial pressure in subdural haemorrhages?
The massive increase in oncotic and osmotic pressure sucks water into the haematoma, gradual rise in ICP
How are subdural haemorrhages diagnosed?
CT/MRI shows clot - look for crescent-shaped collection of blood over 1 hemisphere (sickle-shape differentiates subdural from extradural)
How are subdural haemorrhages managed?
Address the cause, surgical evacuation of the clot
What is an extradural haemorrhage?
Bleeding from the middle meningeal artery with a characteristic lucid period
Between what layers do extradural haemorrhages occur?
Dura and the skull
Why is there a lucid period for extradural haemorrhages?
Accumulation of extradural blood is slow, as the firmly adherent dura is slowly peeled away from the inner surface of the skull
What causes an extradural haemorrhage?
Traumatic skull fracture - temporal or parietal bone causing laceration of the middle meningeal artery and vein
Tear in a dural venous sinus
How do extradural haemorrhages present?
Severe headache, vomiting, confusion, seizures
Continued bleeding Ipsilateral pupil dilates, coma deepens, bilateral limb weakness
Death - respiratory arrest
How long may the lucid interval for extradural haemorrhages last?
A few hours to a few days before a bleed declares itself by low GCS (Glasgow coma scale) from rising ICP
Patients may appear well for several hours following a head injury but then quickly deteriorate as the haematoma enlarges and compresses the brain
How are extradural haemorrhages diagnosed?
CT - haematoma
Skull X-ray may be normal or show fracture lines crossing meningeal vessels
How are extradural haemorrhages managed?
Urgent clot evacuation
Care of the airway and lowering ICP often require intubation and ventilation
What is epilepsy?
A recurrent tendency to spontaneous episodes of abnormal electrical activity within the brain which manifest as seizures
What are partial/focal epileptic seizures?
Originating within networks linked to one hemisphere and often seen with underlying structural disease
What are generalised epileptic seizures?
Features not referable to one hemisphere, consciousness always impaired
What are the causes of epilepsy?
Idiopathic
May be associated with underlying structural lesions e.g. neoplasms, metabolic conditions e.g. electrolyte disorders, infections, rare genetic diseases
What is an aura of an epileptic seizure?
Aura: implies a focal seizure, often from the temporal lobe. May be a strange feeling in the gut or flashing light
What general symptoms might occur after an epileptic seizure (post-ictally)?
Headache, confusion, myalgia
What symptoms may occur after an epileptic seizure affecting the temporal lobe?
Emotional disturbance, dysphasia, hallucinations
What symptoms may occur after an epileptic seizure affecting the frontal lobe?
Motor features such as peddling movements of the legs. Motor arrest, dysphasia or speech arrest
What symptoms may occur after an epileptic seizure affecting the parietal lobe?
Sensory disturbances - tingling, numbness, pain. Motor symptoms
What symptoms may occur after an epileptic seizure affecting the occipital lobe?
Visual phenomena such as spots, lines, flashes
How is epilepsy diagnosed?
Thorough history - often from a witness of a seizure
Ask about triggers e.g. flickering lights
Rule out provoking causes e.g. trauma, stroke, alcohol withdrawal
MRI: structural lesions
How is epilepsy managed pharmacologically?
Anti-Epileptic drugs
Status-Epilepticus - IV Lorazepam
Focal: carbamazepine
Generalised: Sodium valproate
How is epilepsy managed non-pharmacologically?
Psychological therapies - relaxation, CBT
Surgical intervention - neurosurgical resection
What are the different subtypes of generalised seizures?
Absence - brief pauses
Tonic-clonic - loss of consciousness. Limbs stiffen then jerk
Myoclonic - sudden jerk of a limb, face or trunk
Tonic - sudden sustained stiffening of the body not followed by jerks
Atonic - sudden loss of muscle tone causing a fall
What is dementia?
A neurodegenerative syndrome with progressive decline in several cognitive domains
What are the different types of dementia?
Alzheimer’s, Lewy body, Parkinson’s, vascular