Flashcards in BCSC Plastics Deck (238)
What percent of patients with congenital ptosis develop amblyopia?
What congenital conditions involve both EOM dysfunction and ptosis?
1) combined superior rectus/levator muscle maldevelopment; 2) congenital oculomotor palsy
What acquired conditions involve both EOM dysfunction and ptosis?
1) ocular or systemic myasthenia gravis; 2) Chronic progressive external ophthalmoplegia (CPEO); 3) oculopharyngeal dystrophy; 4) oculomotor palsy with or without aberrant regeneration
What conditions involve both ptosis and pupillary abnormalities?
1) Horner syndrome, 2) CN III palsy
How is functional visual impairment assessed in patients with ptosis?
Visual field testing with the eyelids untaped (natural state) and taped (approximating post-surgical state)
What is the most common etiology of congenital myogenic ptosis?
dysgenesis of the levator muscle
What are common causes of acquired or late-onset myogenic ptosis?
muscular dystrophy, chronic progressive external ophthalmoplegia, oculopharyngeal dystrophy
What is the most common form of ptosis?
Acquired aponeurotic ptosis
What is the mechanism of aponeurotic ptosis?
stretching or dehiscence of the levator aponeurosis or disinsertion from its normal position
Is the upper eyelid crease usually higher or lower than normal in acquired aponeurotic ptosis?
What are the causes of congenital neurogenic ptosis?
Congenital CN III palsy, congenital Horner syndrome, Marcus-Gunn jaw-winking syndrome
What is the cause of ptosis in Horner syndrome?
an innervational deficit to the sympathetically innervated Muller muscle (an eyelid elevator second in importance to the levator)
What is the analog of the Muller muscle in the lower lid?
The inferior tarsal muscle
What effect does Horner syndrome have on the inferior tarsal muscle?
since the inferior tarsal muscle, like the Muller muscle, has sympathetic innervation, decreased retraction of the lower lid occurs, resulting in a higher than normal lower lid (sometimes called a lower eyelid reverse ptosis)
What are the two common causes of acquired oculomotor nerve palsies?
1) Ischemic (can be self-limited, especially if pupil-sparing) and 2) Compressive
What percent of myasthenia gravis patients have thymomas?
10%, thus warranting consideration of chest CT scanning at time of diagnosis
What are the tests available for myasthenia gravis?
1) edrophonium test; 2) ice-pack test (which exploits inhibition of acetylcholinesterase at low temperatures); 3) sleep/rest test; 4) acetylcholine receptor antiody test
What are the common medical treatments for myasthenia gravis?
acetylcholinesterase inhibitors and steroids
What surgical intervention is sometimes performed for myasthenia gravis after medical treatments are attempted?
What is dermatochalasis?
a condition in which excess upper eyelid skin overhangs the eyelid margin, transects the pupil, and gives the appearance of a true ptosis of the eyelid margin
What are the 3 categories of surgical procedures commonly used in ptosis repair?
1) External (transcutaneous) levator advancement; 2) internal (transconjunctival) levator/tarsus/Muller muscle resection approaches; 3) frontalis muscle suspensions
What are the most common causes of eyelid retraction?
1) Thyroid eye disease, 2) recession of the vertical rectus muscles, 3) overly aggressive skin excision in blepharoplasty, 4) overcompensation for a contralateral ptosis
What histological changes are seen in the eyelid retractors in TED?
inflammatory infiltration and fibrotic contraction of the sympathetically innervated retractors (Muller muscle and inferior tarsal muscle)
What is the most common cause of paralytic ectropion?
CN VII paralysis or palsy
What is the most commonly performed procedure for treatment of paralytic lagophthalmos?
gold weight loading of the upper eyelid
Is neuroimaging indicated in the workup of blepharospasm?
What are the clinical features of Benign Essential Blepharospasm?
increased blinking, involuntary spasm of the eyelid protractor muscles; may progress to intermittent episodes of inability to open the eyelids
What is the treatment of choice for Benign Essential Blepharospasm (BEB)?
repeated periodic injection of botulinum toxin A
What are the kinetics of botulinum toxin A injections?
Onset: 2-3 days, Peak effect: 7-10 days, Duration of action: 3-4 months