A 34-year-old woman reports intermittent double vision and drooping of the right eyelid that worsen toward evening and improve after rest. Examination shows a right hypertropia that varies between visits, mild right ptosis, and normal pupils. Which bedside manoeuvre should be performed next?

• A Parks three-step test to identify the paretic cyclovertical muscle
• B Superior rectus recession with adjustable sutures
• C Magnetic resonance imaging of the orbit with contrast
• D Ice pack test applied over the closed right eyelid for two minutes ✓

Explanation

Fluctuating, fatigable vertical deviation with ptosis in a young adult strongly suggests ocular myasthenia gravis, which can mimic almost any incomitant strabismus including isolated vertical palsies. The ice pack test is the simplest bedside confirmatory test: cooling improves neuromuscular transmission, so ptosis measurably lifts within minutes, supporting the diagnosis before referral for antibody testing. A positive Parks three-step test here would be misleading because myasthenia produces non-localising patterns, and surgery is contraindicated until the myasthenia is diagnosed and stabilised.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.