Ptosis: Causes and Pathogenesis

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Questions and Answers

What is the primary function of the levator muscle in relation to the eyelid?

To regulate the size of the pupil

To rotate the eye

To control the movement of the jaw

To elevate the upper eyelid (correct)

A patient with ptosis has a maximum travel of 10 mm from full upgaze to full downgaze. What can be inferred from this measurement?

The patient has a normal levator muscle function

The patient has a normal upper eyelid position

The patient has a partially paralyzed levator muscle (correct)

The patient has a complete levator muscle palsy

What is the term for the congenital mis-wiring of the nerve supply to the pterygoid muscle of the jaw and the levator of the eyelid?

Horner's syndrome

Third nerve palsy

Myasthenia gravis

Marcus-Gunn jaw-winking syndrome (correct)

What is a common compensatory event in the presence of ptosis?

Elevation of the eyebrows Signup and view all the answers

What is a possible underlying cause of ptosis in elderly patients?

Disinsertion of the aponeurosis of the levator muscle Signup and view all the answers

What is a symptom of ptosis?

Impaired vision Signup and view all the answers

What is a sign of ptosis?

Reduced palpebral aperture Signup and view all the answers

What is a possible mechanical factor contributing to ptosis?

Lid oedema Signup and view all the answers

What is the main purpose of the Cogan's twitch test in myasthenia gravis diagnosis?

To observe the lid overshoot and fall after a period of rest Signup and view all the answers

What is the primary reason for surgical correction of ptosis in very young children?

To prevent amblyopia Signup and view all the answers

What is the most common cause of entropion in elderly patients?

Weakened orbicularis muscle Signup and view all the answers

What is the effect of botulinum toxin injection into the palpebral part of the orbicularis muscle of the lower lid in entropion treatment?

Temporary alleviation of entropion Signup and view all the answers

What is the main cause of epiphora in ectropion?

Malposition of the lids Signup and view all the answers

What is the primary difference between entropion and ectropion?

Entropion is an inturning of the lid margin, while ectropion is an eversion Signup and view all the answers

What is the purpose of applying lubricants to the eye in entropion treatment?

To alleviate eye irritation Signup and view all the answers

What is the result of manual retraction of the upper lid in myasthenia gravis patients?

Ptosis of the fellow eye Signup and view all the answers

Study Notes

Ptosis

Abnormally low position of the upper eyelid
Caused by:
- Mechanical factors:
  - Large lid lesions pulling the lid down
  - Lid oedema
  - Tethering of the lid by conjunctival scarring
  - Structural abnormalities, including disinsertion of the aponeurosis of the levator muscle
- Neurological factors:
  - Third nerve palsy
  - Horner's syndrome due to a sympathetic nerve lesion
  - Marcus-Gunn jaw-winking syndrome (congenital mis-wiring of nerve supply)
- Myogenic factors:
  - Myasthenia gravis
  - Muscular dystrophy
  - Chronic external ophthalmoplegia

Symptoms and Signs of Ptosis

Cosmetic concerns
Impaired vision
Symptoms and signs associated with the underlying cause (e.g. asymmetric pupils, diplopia, reduced eye movements)
Reduction in size of the palpebral aperture
Upper lid margin may partially cover the pupil or the eye may be completely closed
Elevated eyebrows as a compensatory event

Diagnostic Tests for Myasthenia Gravis

Repeated elevation and depression of the eye results in increased ptosis
Manual retraction of the upper lid causes ptosis or increased ptosis in the fellow eye
Cogan's twitch test: look down for 15 seconds, then look up at an elevated target, and the lid overshoots and then falls slightly
Ice test: apply ice to the lid for 2 minutes, significantly reduces myasthenic ptosis

Management of Ptosis

Surgical correction in the absence of medically treatable disease
Deferred in very young children, expedited if visual axis is covered and threatens amblyopia

Entropion

Inturning of the lid margin and lashes towards the globe
Usually occurs in the lower lid, especially in elderly patients with weakened orbicularis muscle
Can be caused by conjunctival scarring, drawing the lid inwards (cicatricial entropion)
Symptoms: marked irritation, red eye, corneal abrasion
Short-term treatment: lubricants, taping the lid to turn lashes away from the globe
Permanent cure: surgery or botulinum toxin injection into the orbicularis muscle

Ectropion

Eversion of the lid away from the globe
Caused by:
- Age-related orbicularis muscle laxity
- Scarring of the periorbital skin
- Seventh nerve palsy
Symptoms: malposition of the lids, everted puncta, epiphora

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Description

This quiz covers the causes and pathogenesis of ptosis, an abnormally low position of the upper eyelid, including mechanical and neurological factors.