Pupillary Defects
February 15th, 2021
Horner's Syndrome
Horner's syndrome is a classic triad that occurs due to compression of the sympathetic chain.
Look For
- Partial ptosis: drooping of the eyelid
- Miosis: pupillary constriction
- Anhidrosis: lack of sweating
Causes of Horner's Syndrome
- Brain lesion - hypothalamus, thalamus, pons, medullaTumour, bleed
- Spinal cord lesionTrauma, inflammation, AVM, demyelination, tumour, infarct
- Apical lung lesion (Pancoast syndrome)
- Brachial plexus lesion
Oculomotor Nerve (III) Palsy
Look For
- Eye deviated down and out
- Diplopia
- Ptosis
- Mydriasis: pupillary dilatation
- Loss of pupillary reflexes
Causes of Occulomotor Nerve Palsy
- Small-vessel ischaemia
- Midbrain infarct
- Head trauma
- Tumour
- Aneurysm (commonly PCA)
Adie's Tonic Pupil
Look For
- Dilatation of one or both pupils
- Unresponsiveness to light
- Intact accomodation reflex (near light dissociation)
Significance
- Indicates loss of postganglionic parasympathetic innervation of the sphincter pupillae and ciliary muscles.
This finding is commonly associated with knee / ankle areflexia (Holmes-Adie syndrome)
Causes of Adie's Tonic Pupil
- Viral infection
- Trauma
- Orbital tumour
- Vasospasm (migraine)
- Idiopathic
Argyll Robertson Pupil
Look For
- Pupillary constriction
- Unresponsiveness to light
- Intact accomodation reflex (near light dissociation)
Significance
- Previously pathognomonic for neurosyphillis, though more recently associated with conditions affecting the Edinger Westphal nucleus (accessory occulomotor nucleus) within the midbrain.
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