Neurology 2 Flashcards
What is essential tremor?
What makes it worse? What makes it better?
an autosomal dominant condition which usually affects both upper limbs
Symmetrical fine tremor (6-12 Hz)
postural: worse if arms outstretched
worse with tiredness, caffeine and stress
improved by alcohol and rest, completely absent during sleep
Other than the hands, where may be affected by essential tremor?
head tremor, jaw tremor and vocal tremor
most common cause of titubation (head tremor)
How can essential tremor be managed?
propranolol is first-line
Give some ddx for a patient with tremor?
Essential tremor
Parkinson’s disease
Dopamine antagonists (e.g. antipsychotics)
Multiple sclerosis
Huntington’s chorea
Hyperthyroidism
Fever
Anxiety
What is Horner’s syndrome?
Triad of:
miosis (small pupil)
ptosis
anhidrosis (loss of sweating one side)
May include enophthalmos (sunken eye)
Caused by damage to the sympathetic nervous system supplying the face
How can you distinguish between causes of Horner’s syndrome based on clinical signs alone?
heterochromia (difference in iris colour) is seen in congenital Horner’s
Anhidrosis of the face, arm and trunk = central lesion
Anhidrosis of the face = pre-ganglionic lesion
No anhidrosis = post ganglionic lesion
How can you test for Horner’s syndrome pharmacologically?
apraclonidine drops (an alpha-adrenergic agonist) can be used: causes pupillary dilation in Horner’s syndrome but produces mild pupillary constriction in the normal pupil
What is the classical history of an acoustic neuroma?
a combination of vertigo, hearing loss, tinnitus and an absent corneal reflex
What may cause bilateral acoustic neuromas?
neurofibromatosis type 2
How should patients with a suspected acoustic neuroma be investigated and managed?
referred urgently to ENT
MRI of the cerebellopontine angle
Audiometry: only 5% of patients will have a normal audiogram.
Mx = surgery, radiotherapy or observation
What can be seen on this MRI?
vestibular schwannoma (acoustic neuroma) of the right cerebellopontine angle
What is Subacute combined degeneration of the spinal cord?
impairment of the lateral corticospinal tracts, dorsal columns and spinocerebellar tracts due to vitamin B12 deficiency
What sxs may dorsal column involvement in subacute combined degeneration of the cord present with?
distal tingling/burning/sensory loss is symmetrical and tends to affect the legs more than the arms
impaired proprioception and vibration sense
What sxs may lateral corticospinal tract involvement in subacute combined degeneration of the cord present with?
muscle weakness, hyperreflexia, and spasticity
upper motor neuron signs typically develop in the legs first
brisk knee reflexes
absent ankle jerks
extensor plantars
What sxs may spinocerebellar tract involvement in subacute combined degeneration of the cord present with?
sensory ataxia → gait abnormalities
positive Romberg’s sign
How can subacute combined degeneration of the spinal cord be managed?
high-dose vitamin B12 supplementation
can help to reverse the neurological symptoms and prevent further damage
Cavernous sinus thrombosis (CST) refers to the formation of a clot within the cavernous sinus.
What causes this?
most common cause of CST is infection
typically spreads from an extracranial location such as the orbit, paranasal sinuses, or the ‘danger zone’ of the face
Infection is able to spread due to the anastomosis between the facial vein and superior ophthalmic veins
How may cavernous sinus thrombosis present?
headache, unilateral periorbital oedema, proptosis (eye bulging), photophobia and cranial nerve palsies
the abducens nerve (CN VI) is most commonly affected
If it is due to infection, it can rapidly progress to meningitis, so requires prompt tx with abx
A pituitary adenoma is a benign tumour of the pituitary gland. They account for around 10% of adult brain tumours.
How may they be classified?
Pituitary adenomas can be classified according to:
size (a microadenoma is <1cm and a macroadenoma is ≥1cm)
hormonal status (a secretory/functioning adenoma produces an excess of a particular hormone and a non-secretory/functioning adenoma does not)
What is the most common type of pituitary tumour?
Prolactinomas are the most common type
After prolactinomas, non-secreting adenomas are the next most common, then GH-secreting and then ACTH-secreting adenomas.
How may pituitary tumours present?
excess of a hormone (e.g. Cushing’s disease due to excess ACTH, acromegaly due to excess GH or amenorrhea and galactorrhea due to excess prolactin)
depletion of a hormon / generalised hypopituiatrism (due to compression of the normal functioning pituitary gland)
stretching of the dura around the pituitary fossa (causing headaches)
compression of the optic chiasm (causing a bitemporal hemianopia due to crossing nasal fibers)
How may pituitary adenomas be investigated?
a pituitary blood profile (including GH, prolactin, ACTH, FSH, LSH and TFTs)
formal visual field testing
MRI brain with contrast
Give some ddx for a pituitary adenoma
pituitary hyperplasia
craniopharyngioma
meningioma
brain metastases
lymphoma
hypophysitis
vascular malformation (e.g. aneurysm)
How may pituitary adenomas be managed?
medical therapy:
prolactinomas = dopamine agonists (cabergoline or bromocriptine)
GH-secreting adenomas= somatostatin analogues (e.g. octreotide)
transsphenoidal surgery:
non-functioning adenomas are generally diagnosed due to their compressive symptoms - surgery is therefore the first-line treatment
radiotherapy: for residual or recurrent tumours post-surgery
What is Wernicke’s encephalopathy?
a neuropsychiatric disorder caused by thiamine deficiency which is most commonly seen in alcoholics
classic triad of ophthalmoplegia/nystagmus, ataxia and encephalopathy may occur
What features may Wernicke’s encephalopathy present with?
oculomotor dysfunction:
nystagmus (the most common ocular sign)
ophthalmoplegia: lateral rectus palsy, conjugate gaze palsy
gait ataxia
encephalopathy: confusion, disorientation, indifference, and inattentiveness
peripheral sensory neuropathy
How may Wernicke’s encephalopathy be investigated and managed?
Investigations:
bloods: decreased red cell transketolase
MRI
Treatment is with urgent replacement of thiamine
What is Korsakoff’s syndrome?
Wernicke’s encephalopathy with the addition of antero- and retrograde amnesia and confabulation
What is Argyll Robertson pupil?
Classic pupillary syndrome
Small, irregular pupils
Accommodation Reflex Present (ARP) but Pupillary Reflex Absent (PRA)
Causes: diabetes mellitus, syphilis
What is Creutzfeldt-Jakob disease (CJD)?
rapidly progressive neurological condition caused by prion proteins
Sporadic CJD accounts for 85% of cases
presents with dementia (rapid onset) and myoclonus
How can CJD be investigated?
CSF is usually normal
EEG: biphasic, high amplitude sharp waves (only in sporadic CJD)
MRI: hyperintense signals in the basal ganglia and thalamus
What is Syringomyelia?
What can cause it?
Syringomyelia (‘syrinx’ for short) is a collection of CSF within the spinal cord.
Causes include:
a Chiari malformation: strong association
trauma
tumours
idiopathic
How does Syringomyelia present?
‘cape-like’ (neck, shoulders and arms) loss of sensation to temperature
spastic weakness (predominantly of the lower limbs)
neuropathic pain
autonomic features:
Horner’s syndrome
bowel and bladder dysfunction
What causes the cape like loss of sensation in Syringomyelia?
loss of sensation to temperature but the preservation of light touch, proprioception and vibration
this is due to the crossing spinothalamic tracts in the anterior commissure of the spinal cord being the first tracts to be affected
How can Syringomyelia be investigated and managed?
Investigations:
full spine MRI with contrast to exclude a tumour or tethered cord
a brain MRI is also needed to exclude a Chiari malformation
Tx: shunt into the Syringomyelia
What is Hypoxic ischaemic encephalopathy (HIE)?
prolonged or severe hypoxia leading to ischaemic brain damage in neonates
should be suspected when there are events that could lead to hypoxia during birth, acidosis (pH < 7) on the umbilical artery blood gas, poor Apgar scores, or evidence of multi organ failure
What are the potential complications of HIE?
cerebral palsy and death
What may cause HIE?
Maternal shock
Intrapartum haemorrhage
Prolapsed cord, causing compression of the cord during birth
Nuchal cord, where the cord is wrapped around the neck of the baby
How can HIE be managed?
supportive care with neonatal resuscitation and ongoing optimal ventilation, circulatory support, nutrition, acid base balance and treatment of seizures
therapeutic hypothermia
How does a third nerve (oculomotor) palsy present?
eye is deviated ‘down and out’
ptosis
pupil may be dilated (sometimes called a ‘surgical’ third nerve palsy)
What may cause a third nerve palsy?
diabetes mellitus
vasculitis e.g. temporal arteritis, SLE
posterior communicating artery aneurysm (pupil dilated, often associated pain)
cavernous sinus thrombosis
Weber’s syndrome: ipsilateral third nerve palsy with contralateral hemiplegia - caused by midbrain strokes
What is the main function of the 4th cranial nerve (trochlear) ?
supplies superior oblique (depresses eye, moves inward)