Talley Neuro Flashcards
Loss of facial pain/temperature but preserved light touch
Medullary or upper cervical fifth nerve lesion
Horner’s Syndrome
- Carcinoma of lung apex (Squamous Cell)
- Neck mass - Thyroid malignancy, trauma
- Carotid arterial lesion - aneurysm or dissection
- Brain stem lesion - vascular disease, syringobulbia, tumour
- Retro-orbital lesions
- Syringomyelia (rare)
Light Reflex
Constriction - No cortical involvement. Involves optic nerve and tract, Edinger-Westphal nucleus and efferent parasympathetic fibres
Accomodation
Cortex –> Convergence of the pupil with accomodation. Parasympathetic fibres in third nerve
Absent light reflex but intact accommodation
- Midbrain lesion (Argyll Robinson pupil)
- Ciliary ganglion lesion
- Parinaud’s syndrome
- Bilateral anterior visual pathway lesions (bilateral afferent pupil deficits)
Absent convergence but inact light reflex
- Cortical lesion (cortical blindness)
- Midbrain lesion (rare)
Causes of Constriction
- Horner’s Syndrome
- Argyll Robertson pupil
- Pontine lesion (often bilateral but reactive to light)
- Narcotics
- Pilocarpine drops
- Old age
Causes of dilatation
- Mydriatics, atropine poisoning or cocaine
- Third nerve lesion
- Adie’s pupil
- Iridectomy, lens implant, iritis
- Post-trauma, deep coma, cerebral death
- Congenital
Tunnel vision
Glaucoma, papilloedema
Central scotomata
Optic nerve head to chiasmal lesion
- Demyelination
- Toxic
- Vascular
- Nutritional
Unilateral field loss
Optic nerve lesion
- Vascular
- Tumour
Lower Quadrant Homonymous Hemianopia
Parietal lobe
Upper Quadrant Homonymous Hemianopia
Temporal Lobe
Aide’s Syndrome
Lesion in efferent parasympathetic pathway
Signs
- Dilated pupil
- Decrease or absent reaction to light (direct and consensual)
- Slow or incomplete reaction to accommodation with slow dilation afterwards
- Decreased tendon reflexes
- Commonly in young women
Argyll Robinson Pupil causes
Lesion of the iridodilator fibres in the midbrain:
- Syphilis
- Diabetes Mellitus
- Alcoholic midbrain degeneration (rarely)
- Other midbrain lesions
Argyll Robinson Pupil signs
- Small, irregular, unequal pupil
- No reaction to light
- Prompt reaction to accommodation
- If tabes associated, decreased reflexes
Causes of optic neuropathy
- Multiple Sclerosis
- Toxins - ethambutol, chloroquine, nicotine, alcohol
- Metabolic (B12)
- Ischaemia
- Familial (Leber’s disease)
- Infective (EBV)
Third nerve palsy features
- Complete ptosis (or partial ptosis)
- Divergent strabismus (eye ‘down and out’)
- Dilated pupil unreactive to direct or consensual light and unreactive to accommodation
Differential for eye movement abnormality not explained by CN lesion
Neuromuscular myopathy
Ocular myopathy (mitochondrial myopathy) - do not worsen with repetition or maintenance
Third Nerve Palsy Aetiology
Central
- Vascular
- Tumour
- Demyelination
- Trauma
- Idiopathic
Peripheral
- Compressive lesion
- Aneurysm, tumour causing raised ICP, nasopharyngeal carcinoma, basal meningitis
- Infarction
- Trauma
- Cavernous sinus lesion
Sixth Nerve Palsy Features
Failure of lateral movement
Affected eye is deviated inwards in severe lesions
Diplopia - Horizontal, outermost image from affected eye, maximal looking to affected side
Sixth Nerve Palsy Causes
Bilateral - Trauma, Wernicke’s, Raised ICP, Mononeuritis Multiplex
Unilateral:
Central - Vascular, tumour, Wernicke’s encephalopathy, multiple sclerosis
Peripheral - Diabetes, trauma, idiopathic, raised ICP
Causes of Horizontal Nystagmus
Vestibular - Fast phase away from side of lesion
Cerebellar - Nystagmus to the side of the lesion
INO - Nystagmus in abducted (contralateral) eye with failure of adduction in the affected eye.
One and a half syndrome
MLF and abducens nucleus on same side affected - only horizontal movement the eye can make is abduction of the contralateral side
