Pupillary dilation

Overview
The action of the iris dilator muscle is controlled by the sympathetic system, which in turn controls pupillary dilation. The superior cervical ganglion is the source of the third order neuron and follows the internal cartoid artery brances. Sympathetic activity that goes unopposed can cause unequal pupil size.

Differential diagnosis of causes of pupillary dilation
In alphabetical order


 * Acute Closed Angle glaucoma
 * Adie's tonic pupil
 * Adregenic agents
 * Benign episodic mydriasis
 * Coma
 * Congenital mydriasis
 * Drug withdrawal
 * Hallucinogens
 * Seizures
 * Serotonin syndrome
 * Systemic anticholinergics
 * Third nerve palsy
 * Trauma

History and Symptoms

 * Complete history with special attention to:
 * neurologic
 * Ophthalmologic
 * Otolaryngologic

Eyes

 * Pupil size (light & dark)
 * Pupil response to light and convergence
 * Lid position

MRI and CT

 * MRI to check for third cranial nerve palsy

Acute Pharmacotherapies

 * Adie's pupil - Pilcarpine .125% BID-QID
 * Migraines - pain meds, antidepressants, anticonvulsants, beta blockers, calcium channel blockers

Primary Prevention

 * Remove causative medication
 * Sunglasses to decrease light sensitivity