Neurology Flashcards
What is the pathophysiology of an ischaemic stroke?
Stenosis or occlusion of a cerebral artery, often associated with prothrombotic states.
What are the three pathophysiologies of ischaemic stroke?
- Primary vascular pathology (directly reduce cerebral perfusion)
- Cardiac pathologies (cerebral artery occlusion)
- Haematological pathologies (cerebrovascular thrombus)
What are the risk factors for an ischaemic stroke?
- Age
- Family history
- Hypertension
- Smoking
- Diabetes mellitus
- Atrial fibrillation
- Comorbid cardiac condition
What are the signs and symptoms of an ischaemic stroke?
- Vision loss/field defect
- Muscle weakness
- Aphasia
- Ataxia
- Sensory loss
- Headache
- Diplopia
- Dysarthria (slurred words)
- Gaze paresis
How is an ischaemic stroke diagnosed?
Non-contrast CT head
- Hypoattenuation of brain parenchyma
- Loss of grey matter-white matter differentiation
- Hyperattentuation in an artery
What are the differentials for an ischaemic stroke?
- Intracerebral haemorrhage
- Epileptic seizure
- Space occupying lesion
- Infection
- MS
- FND
- Migraine
- Metabolic changes (eg. alcohol/drugs)
How is an ischaemic stroke managed?
- Mechanical thrombectomy
- Thrombolysis
- Aspirin
- Statins 48 hours after
What are the possible complications of an ischaemic stroke?
- DVT
- Haemorrhagic transformation
- Depression
- Aspiration pneumonia
What is the pathophysiology of a haemorrhagic stroke?
Vascular rupture → bleeding into brain parenchyma → primary mechanical injury to brain
What are the risk factors for haemorrhagic stroke?
- Hypertension
- Old age
- Male sex
- Asain/black/hispanic
- Alcohol use
- Sympathomimetic drugs
- FHx
- Anticoagulation
What are the signs and symptoms of haemorrhagic stroke?
- Unilateral weakness
- Sensory loss
- Dysphasia/dysarthria
- Photophobia
- Headache
- Confusion
- N+V
- Decreased consciousness
How is haemorrhagic stroke diagnosed?
Non-contrast CT head
- Hyperattenuation suggesting acute blood
- Surrounding hypoattenuation due to oedema
What are the differentials for haemorrhagic stroke?
- Ischaemic stroke
- Hypersensitivity encephalopathy
- Hypoglycaemia
- Complicated migraine
- Seizure disorder
How are haemorrhagic strokes managed?
- Manage comorbidities
- Craniotomy
- Drugs to relieve pressure (eg. manitol)
- Stereotactic aspiration
Management depends on type of stroke
What are the complications of haemorrhagic strokes?
- Infection
- DVT/PE
- Seizures
- Delirium
- Aspiration pneumonia
What is a transient ischaemic attack?
A transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia.
No acute infarction, sudden onset and usually lasts between 1 and 24 hours.
What is the pathophysiology of a TIA?
Severity depends on a combination of:
- Degree of obstruction
- Area and function of tissue supplied by the vessel
- Length of time thrombus obstructs the vessel
- Ability of collateral circulation to provide supplemental perfusion
What are the causes of TIA?
- Stenosis or unstable atherosclerotic plaques
- Cardioembolic events (impaired ejection fraction)
- Microatheromas, fibrinoid necrosis etc
What are the risk factors for a TIA?
- CVD
- Diabetes mellitus
- Hyperlipidaemia
- Smoking
- Alcohol
What are the signs and symptoms of a TIA?
- Sudden onset and brief duration
- Focal neurological deficit
- Unilateral weakness
- Dysphasia
- Ataxia, vertigo/loss of balance
- Homonymous hemianopia/diplopia
How is a TIA diagnosed?
Clinical diagnosis
What are the differentials for TIA?
- Stroke
- Hypoglycaemia
- Post-seizure paralysis
- Complex migraine
- Conversion disorder
- MS
- Peripheral neuropathy
- Labyrinthine disorders
What is the management of a TIA?
Aspirin and clopidogrel
What are the possible complications of a TIA?
- Stroke
- MI
What is the pathophysiology of a subarachnoid haemorrhage?
- Usually caused by cerebral aneurysms
- Bifurcation of major arteries that form the circle of Willis
What factors increase the risk of aneurysm rupture?
- Size
- Location
- Presence of symptoms
- Multiple aneurysms
- History of ruptured aneurysms
What are the risk factors for subarachnoid haemorrhage?
- Age
- Female sex
- Smoking
- Hypertension
- Alcohol misuse
- FHx
- Acute cocaine use
- Adrenergic/seretonergic drugs
What are the signs and symptoms of subarachnoid haemorrhage?
- Severe sudden-onset headache
- Depressed/loss of consciousness
- Neck stiffness and muscle aches
- Photophobia
- N+V
- Confusion
How are subarachnoid haemorrhages diagnosed?
- Non-contrast CT scan (hyperdense areas in subarachnoid space)
- LP after 24 hours
What are the differentials for subarachnoid haemorrhage?
- Aortic dissection
- Cerebral arteriovenous malformation
- Dural arteriovenous fistulae
- Vasculitis
- Cardiac myxoma
- Cocaine abuse
- Sickle cell disease
What is the management of a subarachnoid haemorrhage?
- Nimodipine (prevents ischemia)
- Neurosurgery to secure aneurysm
- Observe for signs of deterioration
What are the possible complications of subarachnoid haemorrhage?
- Neuropsychiatric problems
- Chronic hydrocephalus
What is the pathophysiology of a subdural haemorrhage?
The result of torsional or sheer forces → disruption of bridging cortical veins → empty into dural venous sinuses
What are the causes of subdural haemorrhage?
- Trauma (most common)
- Increased intracranial pressure
- Mets
What are the risk factors for subdural haemorrhage?
- Alcoholism
- Aspirin/blood thinners
- Age
What are the signs and symptoms of a subdural haemorrhage?
- Drowsiness
- Consciousness fluctuation
- Personality change
- Increased ICP
- Seizures
- Focal neurological signs (unequal pupils)
How are subdural haemorrhages diagnosed?
CT/MRI
- Concave crescent of blood around the edge of the brain
- Midline shift of brain structures
What are the differentials for subdural haemorrhage?
- Stroke
- Dementia
- Mass lesion
What is the management of subdural haemorrhage?
- Irrigation/evacuation/burr hole craniostomy
- Craniotomy
- Identify cause
What are the possible complications of a subdural haemorrhage?
- Neurological deficits
- Coma
- Stroke
- Epilepsy
What is intracerebral haemorrhage?
Rapidly developing clinical signs of neurological dysfunction attributable to a focal collection of blood within the brain parenchyma or ventricular system
What are the symptoms of posterior circulation strokes?
- Unsteadiness
- Visual disturbance
- Slurred speech
- Headache
- Vomiting
What is the pathophysiology of an extradural haemorrhage?
Usually a bleed from the middle meningeal artery and/or vein, normally due to trauma around the eye (fracture of temporal/parietal bone).
What is the presentation of extradural haemorrhage?
- Drowsiness
- Pupil asymmetry
- Impaired consciousness/coma
- Severe headache
- Vomiting
- Seizures
- Hemiparesis
How is an extradural haemorrhage diagnosed?
CT or MRI
Convex lesion
What are the differentials for extradural haemorrhages?
- Subdural haemorrhage
- Meningioma
How is an extradural haemorrhage managed?
- Surgery - 1st line
- Evacuation of blood
- Bleeding lesion ligation - Decompression if required
- Sit up in bed
What is epilepsy?
The tendency to have seizures (not a true condition, more a symptom).
Diagnosed after a minimum of 2 seizures.
What is the pathophysiology of epilepsy?
- Abnormal synchronised discharge of neurones (usually glutamate and GABA neurones)
- Failure of inhibitory mechanisms
What does ‘seizure threshold’ mean?
The level of excitability at which cells will discharge uncontrollably, in epilepsy this is lowered (neurones are hyperexcitable).
What triggers can push neurones past the seizure threshold?
- Sleep deprivation
- Alcohol
- Drug misuse
- Physical/mental exhaustion
- Flickering lights
- Infection/metabolic disturbance
What are the causes of epilepsy?
- Genetic
- Developmental abnormalities
- Trauma/surgery
- Hypoxia
- Pyrexia
- Mass lesion in the skull
- Drugs
- CNS infection
What are the risk factors for epilepsy?
- Age
- FHx
- Head injury
- Stroke (vascular diseases)
- Dementia
- Brain infection
What are the signs and symptoms of a simple partial seizure?
- Remains consciousness
- Isolated limb jerking
- Isolated head turning
- Isolates paraesthesia
- Weakness of limbs follows
What are the signs and symptoms of a complex partial seizure?
- May impair consciousness
- Deja vu
- Vertigo
- Hallucinations
- Lip-smacking (other motor disturbances)
- Tachycardia
- Post-ictal confusion and drowsiness
What are the signs and symptoms of absence seizures?
- Unresponsive to stimuli but still conscious
- Stares/pallor
- Muscle jerking
- Multiple episodes in one day
- Normal function quickly resumes post episode
What are the signs and symptoms of Tonic-Clonic seizures? §
- Aura prior to the episode
- Tonic phase
- Rigidity
- Epileptic cry
- Tongue biting
- Incontinence
- Hypoxia - Clonic phase
- Convulsions
- Eye rolling
- Tachycardia
- Random or uncontrolled breaths
What are the features of generalised epilepsy?
- Absence seizures
- Tonic-Clonic seizures
- Tonic only seizures
- Atonic seizures (presents similar to syncope)
- Myoclonic seizures
What are the features of focal epilepsy?
- Simple partial seizure
- Complex partial seizure
What are the signs and symptoms of status epilepticus?
Seizure >30 minutes
OR
Multiple seizures without regaining consciousness lasting >30 minutes
The brain swells and can cause herniation due to electrolyte imbalance
How is epilepsy diagnosed?
- EEG
- CT/MRI (focal lesions)
- PET scan
- Bloods (CK)
What are the differentials for epilepsy?
- Other causes of falls
- Pseudoseizures
How is epilepsy managed?
- Avoid triggering factors
- Focal seizures - carbamazepine
- Generalised TC - Sodium valproate
- Surgery
How is status epilepticus managed?
Benzodiazepines.
What is meningitis?
Inflammation of the meninges.
Notifiable disease.
What is the pathophysiology of infective meningitis?
- Haematogenous spread
- Binding to surface receptors
- Vulnerable spots/areas of damage - Direct spread
- Anatomical
- Through the nose
- Through overlaying skin
What are the causes of bacterial meningitis? §
- Neisseria meningitides (gram-negative diplococci)
- Strep pneumoniae or pneumococcus
- Haemophilus influenzae
- Listeria monocytogenes (pregnant women)
- E. coli (neonates)
- TB
What are the causes of viral meningitis?
- HSV
- VZV
- Enteroviruses
What are the causes of fungal meningitis?
Cryptococcus neoformans