EpistemisUnilateral pupillary miosis
Specialty: Neurology.
Why it occurs
- Horner syndrome (interruption of the sympathetic chain at any level of its three-neuron pathway: central due to lateral bulbar infarction, preganglionic due to lung apex/Pancoast tumor or aortic dissection, or postganglionic due to carotid dissection)
- Cluster headache and other trigemino-autonomic headaches in active phase
- Cervical trauma with indirect sympathetic injury
- Inadvertently unilateral use of miotic eye drops (pilocarpine) or other ophthalmic agents
- Neuroschistosomiasis or other neuroinfections with high cervical spinal cord focality
Initial workup
Ocular pharmacological test with 0.5% apraclonidine eye drops (the pupil with Horner syndrome dilates due to denervation hypersensitivity, reversing the anisocoria); MRI angiography or CT angiography of the skull and neck from the aortic arch to the circle of Willis to reliably rule out carotid dissection or aneurysms; Chest CT if apical lung mass (Pancoast tumor) is suspected.
red flags
Unilateral miosis of acute onset associated with severe cervical pain (cervicalgia), orbital pain and ipsilateral eyelid ptosis (classic triad of internal carotid artery dissection), which exposes the patient to an imminent risk of extensive ipsilateral ischemic stroke due to embolization.
Standard management
- Acetylsalicylic acid or formal anticoagulation with low molecular weight Heparin followed by oral anticoagulants if carotid dissection is confirmed without contraindications
- Specific analgesic treatment according to the cause of the associated pain.
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Neurology
- Listed causes
- 5
- Treatment options
- 2