Neurology Flashcards
Define multiple sclerosis
Inflammatory demyelinating disease of the CNS
Relapsing-remitting MS: commonest form: clinical attacks of demyelination, with complete recovery between attacks
Clinically isolated syndrome: single clinical attack (doesn’t qualify as MS)
Primary progressive MS: steady accumulation of disability
Explain the aetiology / risk factors of multiple sclerosis
Unknown. Autoimmune basis with postulated environmental trigger (B12 and thyroid problems?)
Risk Factors: EBV exposure
Summarise the epidemiology of multiple sclerosis
1:1000, females 2x risk; present at 20-40 years
closer the equator, lower prevalence. Probably due to vitamin D
Recognise the presenting symptoms of multiple sclerosis
Varies depending on site
Optic neuritis: unilateral deterioration in visual acuity and colour perception. Pain on movement.
Sensory: pins and needles, numbness, burning
Motor: limb weakness, spasms, stiffness, heaviness
Autonomic: urinary urgency, hesitancy, incontinence, impotence
Psychological: depression, psychosis
Uhthoff’s phenomenon: increase/recurrence of symptoms due to conduction block
Recognise the signs of multiple sclerosis on physical examination
Optic neuritis: impaired visual acuity, loss of coloured vision. Fundoscopy – swollen optic nerve head, optic atrophy
Visual field: central scotoma, field defects
Relative afferent pupillary defect: dilation when light swung to diseased eye
Internuclear ophthalmoplegia: failure of adduction in contralateral eye; lesion of contralateral media longitudinal fasciculus
Sensory: paresthesia
Motor: UMN signs
Cerebellar: limb ataxia
Lhermitte’s phenomenon: electric-shock like sensation in arms and legs – precipitated by neck flexion.
Identify appropriate investigations for multiple sclerosis and interpret the results
Diagnosis on ≥2 CNS lesions
Lumbar Puncture: microscopy to exclude other causes
MRI: plaque detection is highlighted
Evoked potentials: visual/auditory/somatosensory evoked potentials, delayed conduction velocity.
Define myasthenia gravis
Autoimmune disease affecting neuromuscular junction producing skeletal muscle weakness
A chronic autoimmune disorder of the post-synaptic membrane at the neuromuscular junction in skeletal muscle.
Explain the aetiology / risk factors of myasthenia gravis
Impairment of neuromuscular junction transmission, due to auto-antibodies against nicotinic acetylcholine receptor.
Associated with other autoimmune conditions (e.g. pernicious anaemia)
Summarise the epidemiology of myasthenia gravis
8-9:100,000; younger females
Recognise the presenting symptoms of myasthenia gravis
Muscle weakness, worsening with repetitive use
Ocular: drooping eyelids, diplopia
Bulbar: facial weakness, disturbed speech, difficulty smiling/chewing/swallowing
Recognise the signs of myasthenia gravis on physical examination
Generalised, bulbar or ocular signs
Eyes: bilateral ptosis (can be alleviated with ice-packs, improvement of ≥2mm from baseline)
Bulbar: reading aloud provokes dysarthria
Limbs: test power of muscle before and after repeated use
Identify appropriate investigations for myasthenia gravis and interpret the results
Blood: serum AChR ab (+ve in 80%), MuSK ab, CK, TFT
serial pulmonary function tests
Nerve Conduction: repetitive stimulation demonstrating decrements of muscle AP
EMG: may demonstrate ‘jitter’
CT-T/CXR: visualize thymoma in mediastinum
Define Guillain-Barré syndrome
Acute inflammatory demyelinating polyneuropathy
Explain the aetiology / risk factors of Guillain-Barré syndrome
Antibodies react with self-antigen on myelin, following infection. Often no trigger is identified (40%)
Other: bacterial, HIV, herpes viruses, malignancy, post-vaccination
Two-thirds have a history of gastroenteritis or influenza-like illness weeks before onset of neurological symptoms.
Recognise the presenting symptoms of Guillain-Barré syndrome
Progressive over <1 month
• Ascending symmetrical limb weakness (lower>upper)
• Ascending paresthesia
Cranial nerve involvement (dysarthria, dysphagia)
Recognise the signs of Guillain-Barré syndrome on physical examination
General Motor: hypotonia, flaccid paralysis, areflexia
General Sensory: impairment in multiple modalities
Cranial Nerves: facial nerve weakness (LMN pattern)
Type II Resp Failure: important early identification
Autonomic Function: postural BP change
Identify appropriate investigations for Guillain-Barré syndrome and interpret the results
Nerve Conduction: reduced velocity/blocked
Lumbar Puncture: high CSF protein, (cell count and glucose normal)
Blood: anti-ganglioside, LFTs
Spirometry: reduced FVC
Explain the aetiology / risk factors of raised intracranial pressure
• Mass lesions
○ Localised mass lesions: traumatic haematomas (extradural,subdural,intracerebral)
○ Neoplasms (tumour):glioma,meningioma, metastasis.
○ Abscess
○ Focal oedema secondary to trauma, infarction, tumour
• Changes to CSF flow (Disturbance of CSF circulation)
○ obstructivehydrocephalus
○ communicating hydrocephalus
(NOTE that CSP increases in response to trauma to cushion the brain)
• Diffuse intracranial pathology. Diffuse brain oedema or swelling: encephalitis, meningitis, diffuse head injury,subarachnoid haemorrhage, Reye’s syndrome, lead encephalopathy, water intoxication, near drowning.
• Obstruction to major venous sinuses: depressed fractures overlying major venous sinuses,cerebral venous thrombosis.
• Idiopathic intracranial hypertension
Recognise the presenting symptoms of raised intracranial pressure
combination of headache, papilloedema and vomiting generally indicative of ICP
• Headache: more worrying when nocturnal, starting when waking, worse on coughing or moving head and associated with altered mental state. worse on lying down
• Early changes in mental state include lethargy, irritability, slow decision making and abnormal social behaviour. confusionabout time, then location and people as the pressure worsens.
• Vomiting (in early stages without nausea), which can progress to projectile with rising ICP.
• Pupillary changes, including irregularity or dilatation in one eye. Double vision.
• Unilateral ptosis or third and sixth nerve palsies. In later stages, ophthalmoplegia and loss of vestibulo-ocular reflexes.
• Late signs include motor changes (hemiparesis), raised blood pressure, widened pulse pressure and slow irregular pulse.
Recognise the signs of raised intracranial pressure on physical examination
hypertension, bradycardia, papilloedema
- Pupillary changes, including irregularity or dilatation in one eye. Double vision.
- Unilateral ptosis or third and sixth nerve palsies. In later stages, ophthalmoplegia and loss of vestibulo-ocular reflexes.
- Late signs include motor changes (hemiparesis), raised blood pressure, widened pulse pressure and slow irregular pulse.
- Fundoscopy shows blurring of the disc margins, loss of venous pulsations, disc hyperaemia and flame-shaped haemorrhages. In later stages, obscured disc margins and retinal haemorrhages may be seen.
Identify appropriate investigations for raised intracranial pressure and interpret the results
MRI head
CT head
Check and monitor blood glucose, renal function, electrolytes and osmolality (FBC, U&Es, CRP)
Intraventricular fluid filled catheter transducer systems represent the “gold standard” for measuring ICP
Define central nervous system (CNS) tumours
Tumours deriving from the Central Nervous System (meninges)
meningioma
Primary tumours arising from any of the brain tissue types.
Explain the aetiology / risk factors of central nervous system (CNS) tumours
Unknown cause Risk factors: • radiotherapy • genetic predisposition (family history of neurofibromatosis type 2 [NF2]) • hormones: endogenous and exogenous • head trauma
Summarise the epidemiology of central nervous system (CNS) tumours
2nd most common childhood cancers
Annual incidence of primary tumours 5–9 in 100000. Two peaks of incidence (children and the elderly).
Recognise the presenting symptoms of central nervous system (CNS) tumours
Seizures, neck tilts/squint, unexplained nausea and vomiting, weakness/clumsiness, early/delayed puberty, sleep apnoea, headache, pain, personality changes • headache • neurological deficit • seizure • family history of NF2
Recognise the signs of central nervous system (CNS) tumours on physical examination
CNS signs of location of tumour (weakness, lack of sensation etc.)
Visual problems, depending on tumour location
Papilloedema/false localizing signs (increased ICP).
Focal neurological deficits (visual field defects, dysphasia, agnosia, hemianopia, hemiparesis, ataxia, personality change).
Identify appropriate investigations for central nervous system (CNS) tumours and interpret the results
MRI head or spine without and with contrast
CT head or spine
Define hydrocephalus
Enlargement of the cerebral ventricular system.
Obstructive and non-obstructive pathologies.
Hydrocephalus ex vacuo is a term for compensatory hydrocephalus in response to atrophy
Explain the aetiology / risk factors of hydrocephalus
Abnormal accumulation of CSF in ventricles
Impaired outflow of CSF (obstructive/non- communicating):
• Lesions of third ventricle/fourth ventricle/aqueduct
• Posterior fossa lesions
• Cerebral aqueduct stenosis
Impaired CSF resorption in subarachnoid villi (non-obstructive/communicating):
• Tumours
• Meningitis
Normal pressure hydrocephalus:
idiopathic, chronic enlargement => long white matter
tract damage => cognitive and gait decline
Summarise the epidemiology of hydrocephalus
Bimodal age distribution; congenital in young and tumours in elderly
Recognise the presenting symptoms of hydrocephalus
Obstructive: acuute drop in consciousness, diplopia
NPH: chronic cognitive decline, falls and urinary incontinence.
Recognise the signs of hydrocephalus on physical examination
Obstructive: impaired GCS, papilloedema, VI nerve palsy
NPH (triad): levodopa-unresponsive gait apraxia with or without cognitive impairment or urinary symptoms
Identify appropriate investigations for hydrocephalus and interpret the results
CT head: 1st line investigation
CSF: ventricular drains or lumbar puncture
Lumbar puncture: contra-indicated in obstructive hydrocephalus (can cause tonsillar herniation and death)
Define Bell’s palsy
Idiopathic lower motor neuron facial nerve (VII) palsy
Explain the aetiology / risk factors of Bell’s palsy
15-40:100,000; equal in M & F. risk in pregnancy and diabetes.
Summarise the epidemiology of Bell’s palsy
Idiopathic. 60% preceded by upper respiratory tract infection – suggesting viral/post-viral aetiology