What is the recommended workup for a new case of ptosis (drooping of the eyelid)?

Diagnostic Workup for New Ptosis

A comprehensive workup for new ptosis should include detailed evaluation of pupillary responses, extraocular muscle function, and neuroimaging when indicated, with particular attention to ruling out potentially life-threatening conditions such as aneurysm in pupil-involving third nerve palsies. 1, 2

Initial Clinical Assessment

• Obtain detailed medical and ocular history, focusing on speed of onset, associated symptoms (diplopia, pain), and any neurological symptoms (ataxia, tremor, hemiplegia) 1
• Document whether ptosis is unilateral or bilateral, and severity (minimal: 1-2mm, moderate: 3-4mm, severe: >4mm) 3
• Perform comprehensive eye examination with particular attention to:
  • Sensorimotor examination to detect strabismus or extraocular muscle dysfunction 1, 2
  • Pupillary responses in both bright and dim illumination to assess for anisocoria 1, 2
  • Fundus examination to evaluate for papilledema or optic atrophy 1

Key Diagnostic Considerations Based on Clinical Findings

Ptosis with Pupillary Involvement

• If pupil-involving third nerve palsy is present, urgent neuroimaging is required to rule out posterior communicating artery aneurysm 1, 2
• Recommended imaging includes MRI with gadolinium and MRA or CTA 1
• If high suspicion for aneurysm despite normal MRA/CTA, consider catheter angiogram 1

Ptosis without Pupillary Involvement

• Classic pupil-sparing third nerve palsy with complete ptosis and motility dysfunction suggests microvascular etiology (diabetes, hypertension, hyperlipidemia) 1
• However, partial involvement of extraocular muscles or incomplete ptosis requires neuroimaging to rule out compressive lesions 1, 2

Variable Ptosis

• For ptosis that worsens with fatigue, consider myasthenia gravis 1, 2
• Diagnostic tests include:
  • Ice test (application of ice pack over closed eyes for 2 minutes) 1
  • Rest test (observation for improvement after period of rest) 1
  • Acetylcholine receptor antibody testing (note: ~50% of ocular myasthenia cases are seronegative) 1
  • Single fiber EMG (most sensitive test, positive in >90% of ocular myasthenia) 1

Specialized Testing Based on Suspected Etiology

Neurogenic Ptosis

• For suspected third nerve palsy:
  • MRI brain with and without contrast 1, 2
  • MRA or CTA to evaluate for aneurysm 1
• For Horner syndrome (ptosis with miosis):
  • Pharmacologic testing with cocaine or apraclonidine 2
  • Consider chest imaging to rule out apical lung tumor 2

Myogenic Ptosis

• For suspected myasthenia gravis:
  • Acetylcholine receptor antibody testing 1
  • Anti-MuSK and LRP4 antibodies in seronegative cases 1
  • Repetitive nerve stimulation and single fiber EMG 1
  • Consider chest imaging to rule out thymoma 1

Mechanical or Aponeurotic Ptosis

• Detailed slit-lamp examination to assess for:
  • Eyelid inflammation, scarring, or masses 1
  • Evidence of prior trauma or surgery 4
  • Orbital masses or proptosis 1, 2

Pitfalls to Avoid

• Failing to recognize pupil-involving third nerve palsy as a potential neurosurgical emergency 1, 2
• Assuming microvascular etiology in pupil-sparing third nerve palsy without thorough evaluation 1
• Missing myasthenia gravis due to variable presentation and potential seronegativity 1, 2
• Overlooking orbital masses or inflammatory conditions that may present with ptosis 1, 2

When to Consider Referral

• Immediate referral for pupil-involving third nerve palsy 1, 2
• Urgent referral for any ptosis with associated neurological symptoms 1, 2
• Referral for variable ptosis suspicious for myasthenia gravis 1
• Referral for ptosis associated with proptosis or suspected orbital mass 2