What are the causes of Adie pupil?

Causes of Adie's Pupil

Adie's pupil is primarily caused by damage to the ciliary ganglion or postganglionic short ciliary nerves, with most cases being idiopathic but several identifiable causes including viral infections, autoimmune conditions, and paraneoplastic syndromes.

Pathophysiology

Adie's pupil (tonic pupil) results from damage to the parasympathetic innervation of the eye, specifically affecting:

• Ciliary ganglion
• Postganglionic short ciliary nerves 1

This damage leads to:

• Dilated pupil unresponsive to light
• Preserved but slow near response (tonic)
• Denervation hypersensitivity to dilute cholinergic agents (0.125% pilocarpine)

Primary Causes

Idiopathic

• Most common cause
• Predominantly affects young women (female:male ratio of 2.6:1) 2
• Mean age of onset approximately 32 years 2

Infectious Causes

• Viral infections:
  • Hepatitis A 3
  • Hepatitis B 3
  • Other viral infections affecting peripheral nerves
• Syphilis (most common infectious cause - 1 in 6 patients in some series) 2, 1

Autoimmune Conditions

• Associated with various autoimmune disorders
• Possible immune-mediated damage to ciliary ganglion

Iatrogenic Causes

• Laser photocoagulation of peripheral retina
  • Particularly when treating retinal ischemia in uveitis 4
  • More extensive laser treatment correlates with more severe symptoms 4

Other Neurological Conditions

• May be part of peripheral neuropathies
• Can be associated with decreased deep tendon reflexes (Adie's syndrome) 2

Secondary Causes

Ocular/Orbital Conditions

• Uveitis 4
• Trauma to the eye or orbit
• Intraocular surgery

Paraneoplastic Syndromes

• Associated with certain malignancies 1

Vascular Causes

• Ischemic damage to ciliary ganglion
• Microvascular disease (e.g., in diabetes)

Clinical Characteristics

• Unilateral in initial presentation (bilateral in approximately 4% per year) 2
• Equal distribution between right and left eyes 2
• Associated with accommodative paresis initially, which often recovers 2
• Segmental paralysis of the iris sphincter visible on careful examination 2
• Supersensitivity to dilute pilocarpine (0.125%) - diagnostic test 2, 1

Differential Diagnosis

Important to distinguish from:

• Oculomotor nerve palsy (will have ptosis and extraocular muscle weakness)
• Anticholinergic drug effects (bilateral, no response to dilute pilocarpine)
• Argyll-Robertson pupil (small pupils, light-near dissociation)
• Congenital mydriasis 1
• Secondary angle closure (may present with mid-dilated pupil) 5

Management Considerations

• Most cases are benign and self-limiting
• Symptoms (photophobia, blurred vision) may improve over time
• Pupil size often decreases over months without treatment 4
• Low-concentration pilocarpine can be used for symptomatic relief 1
• Treat any underlying cause if identified
• Consider reading glasses for temporary accommodative paresis 2

When to Consider Further Evaluation

• Bilateral presentation at onset
• Associated neurological symptoms
• Positive syphilis serology (recommended in all cases) 2
• Lack of denervation hypersensitivity to dilute pilocarpine
• Progressive worsening of pupillary function

Understanding the various causes of Adie's pupil is essential for proper diagnosis and management, as well as for identifying potentially serious underlying conditions that may require specific treatment.