TABLE 3

Causes of a dilated pupil

Unilateral
Trauma
Optic neuritis
Tonic pupil (Adie pupil)
Acute angle-closure glaucoma
Local contamination with drugs such as albuterol, stimulants (cocaine, amphetamine), anticholinergics (scopolamine, atropine, hycosamine)
Compression of cranial nerve III
Uncal herniation
Posterior communicating artery aneurysm
Bilateral
Systemic disease (eg, botulism, paraneoplastic syndrome, Miller Fisher variant of acute inflammatory demyelinating polyneuropathy)
Systemic drugs (eg, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, stimulants such as cocaine and amphetamine)
Midbrain injury
Transient
Unilateral episodic mydriasis
Seizures
Migraine