Head Trauma Flashcards
Name and draw the blood supply to the brain
Circle of Willis
Anterior cerebral artery Anterior communicating artery Middle cerebral artery Internal carotid artery Ophthalmic artery Posterior communicating artery Posterior cerebral artery Superior cerebellar artery Basilar artery Pontine artery Anterior inferior cerebellar artery Vertebral arteries Anterior spinal artery Posterior inferior cerebellar arteries
What is the anterior circulation of the brain?
- The internal carotid artery continuing as the middle cerebral artery
- The anterior cerebral artery
- The posterior communicating artery
What is the posterior circulation of the brain
- Basilar artery
- Vertebral artery
- Posterior cerebral artery
Draw the branches of the aorta.
Ascending aorta - right and left coronary arteries
Arch of aorta
Brachiocephalic trunk –> Right subclavian and right common carotid artery
Left common carotid
Left subclavian
What does the external carotid artery supply
Face, scalp, mouth, jaw
give 3 branches of the ICA. What do they supply?
- Ophthalmic artery – occlusion can lead to ocular ischaemic syndrome as it supplies structures in the orbit as well as other structures
- Posterior communicating artery – aneurysm can lead to third nerve palsy (you can see why when you see how close together they are on the picture)
- Anterior choroidal artery – supplies choroid plexus cells, optic chiasm and optic tract, internal capsule and many other structures
Describe the middle cerebral artery.
The middle cerebral artery is the direct continuation of the internal carotid artery, which carries 60-80% of the flow. It supplies the lateral aspects of the frontal, parietal and occipital lobes. It also gives off the lateral striate branches to the basal ganglia.
Describe the anterior cerebral artery. What does it supply?
The anterior cerebral artery is a smaller branch of the ICA, which supplies the medial surface of the frontal and parietal lobes. They are joined by the anterior communicating artery.
What does the vertebral artery arise form? What does it supply?
The vertebral artery arises from the subclavian arteries and has a tortuous course to the cranium. The largest branch is to the posterior inferior cerebellar artery, it also gives off branches to the spine (the spinal arteries).
Describe the basilar artery and what it supplies. What arteries does it give off?
The basilar artery overlies the pons – it supplies most of the brainstem (pontine arteries) and also gives off branches to the cerebellum (superior and anterior inferior). It bifurcates into the 2 posterior cerebral arteries.
- Describe the posterior cerebral artery and what it supplies.
The posterior cerebral artery is usually a branch of the basilar artery, but 25% get their supply from the ICA. It runs around the midbrain and supplies the midbrain, thalamus, and the temporal and occipital lobes.
- Define stroke
Stroke is the sudden onset of focal neurological symptoms of presumed vascular origin (either haemorrhage into the brain parenchyma or inadequate blood supply following thrombosis or embolism), lasting greater than 24 hours or causing death.
Give some causes of infarcts
Large vessel atheroma and embolism Cardiac embolism Small vessel disease e(lacunar infarcts) Non-atheromatous arterial disease (arteritis) Blood disorders IDiopathic
(tissue death due to disruption of blood supply)
Give some causes of intracranial haemorrhage
• Hypertensive microaneurysms/lipohyalinosis
• Arteriovenous malformations or aneurysms
• Amyloid angiopathy
• Anticoagulant therapy, thrombolysis or thrombocytopenia
• Rarer:
o Cocaine
o Amphetamines
o Tumour
o Venous thrombosis
Symptoms in frontal lobe lesion?
Motor symptoms (pre-motor and motor cortex) Broca’s area – expressive aphasia Prefrontal cortex – changes in personality and behaviour
Symptoms in occipital lobe lesion?
Visual symptoms
Symptoms in parietal lobe lesions?
Primary sensory cortex – sensory loss
Non-dominant hemisphere lesion causes visuospatial problems
Lesions to the superior optic radiations can cause inferior quadrantanopia
Symptoms in temporal lobe lesions?
Wernicke’s area – receptive aphasia Memory affected Affects inferior optic radiations causing superior quadrantanopia Auditory and vestibular dysfunction Taste and smell
Symptoms in cerebellum and brainstem lesions?
Cranial nerve dysfunction
Balance and coordination
Motor and sensory tracts
What are the classifications of stroke?
Total anterior circulation stroke (TACI)
Partial anterior circulation stroke (PACI)
Lacunar stroke (LACI)
Posterior circulation stroke (POCI)
Describe a total anterior circulation stroke
o Proximal occlusion – ICA or proximal MCA – leading to a large infarction affecting superficial and deep brain areas
o Presents with hemiparesis, hemianaesthesia, hemianopia, and higher cerebral dysfunction such as dysphasia or dyspraxia
o High mortality
Describe a partial anterior circulation stroke
o Occlusion of a branch of the MCA
o 2 of the above 3 symptoms (or a restricted motor deficit like face, arm or leg only, or isolated cortical signs)
o They have a high early recurrence rate
Describe a lacunar stroke
o Occlusion of a single perforating artery – for example supplying the basal ganglia or the pons
o May be purely motor, pure sensory, sensorimotor or ataxia
o Often silent – therefore underdiagnosed
Describe a posterior circulation stroke
o Hard to distinguish from syncope and vestibular pathology
o Usually affects brainstem, cerebellum or occipital lobe
o Usually a complex presentation
What are important features of a history in stroke?
Onset - time, speed, progression
Neurological - body part affected, modalities involved, positive/negative symptoms
Other symptoms - RICP -headache, vomiting, drowsiness - bleeding - headache, seizure - particular aetiology - cardiac symptoms.
What are some differentials?
Hypoglycaemia/metabolic disturbance Migranous aura Epilepsy SOL Demyelination Labyrinthine disorders
What should you look for one examination of stroke?
cardiac source of embolus - arrhythmia or valve defects
Carotid or renal bruits
Complications like aspiration penumonia
What investigations for stroke?
BM FBC, clotting, INR U&E, LFT, TFT, glucose, lipids ECG CXR if pneumonia CT/MRI Carotid ultrasound Echo
Thrombophilia screen
Antiphopholipid antibodies
Auoimmune screen
What is tested for in thrombophilia screen?
Protein C, protein S, antithrombin III, Factor V leiden
What is the treatment for ischaemic stroke? haemorrhage stroke?
I - thrombolysis within 3 hours, if not then aspirin
Mechanica thrombectomy
H - reverse anticoagulation, blood pressure reduction, surgery
How can stroke be prevented?
Antihypertensives Lipid lowering drugs Carotid endarterectomy Hypoglycaemic agents Lifestyle changes - fat loss, exercise, diet Adherence to medication Antithrombotics
