Approach to: Ptosis

Question A 75-year-old male presents to the ophthalmology service with a drooping left upper eyelid. Upon further questioning, he states that he feels his visual acuity has deteriorated in the left eye, but only in the dark. On testing his best corrected visual acuity is 20/25 in the right eye and 20/30 in the left eye. His pupils are equal, round, and reactive to light and accommodation. His intraocular pressures are 14mmHg bilaterally. His past medical history is significant for type 2 diabetes mellitus, hypertension, hypercholesterolemia, and obesity. He states that his dropping eyelid does not get better or worse during the day and he first noticed his drooping eyelid this morning. He also states that he has been experiencing some horizontal diplopia since this morning. Your clinical examination reveals no significant ocular misalignment, but the patient is unable to fully adduct, infraduct, or supraduct his left eye. His margin to reflex distance 1 is 2mm and his levator function is markedly decreased. His ESR and CRP are within normal limits. He is scheduled for a follow-up visit in 6 weeks at which point his symptoms have almost completely resolved. Third Nerve palsy Myasthenia gravis Congenital ptosis Horner syndrome Aponeurotic ptosis Answer A) Given his history and clinical examination, this patient likely has a third cranial nerve palsy. Furthermore, given no pupillary involvement and systemic risk factors (obesity, diabetes mellitus, hypertension, hypercholesterolemia), an ischemic third nerve palsy is favoured. Typically, ischemic third nerve palsies are self-resolving and the patient can be scheduled for follow-up in 4-6 weeks. Pupil involvement or a lack of improvement at follow-up are indications for head imaging (CT angiography) to rule out an aneurysm or other compressive causes. In this case, since the ptosis does not worsen as the day goes on and improve after rest, myasthenia gravis is unlikely. Additionally, this autoimmune condition would present at an earlier age than 75. Similarly, congenital ptosis would present in the first years of life. Horner syndrome would include miosis and facial anhidrosis alongside the ptosis. Aponeurotic ptosis is a possible diagnosis, however, is less likely given this presentation with an inability to fully adduct, infraduct, or supraduct his left eye.