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  • YO Need to Know: 5 Causes of Dangerous Asymmetric Ptosis

    Aysmmetric ptosis

    Ptosis can be common in an aging population, but asymmetric ptosis may indicate a potentially serious disease process that needs urgent evaluation. 

    In examining ptosis patients, there’s a so-called “triad of (p)tosis,” including: 

    1. Eyelid position (MRD1 and levator function)
    2. Pupil exam (size and reactivity)
    3. Extraocular motility

    With this foundation in place, here are some tips for evaluating five dangerous causes for asymmetric ptosis. 

    1. Cranial Nerve 3 Palsy

    This can be a partial or complete palsy and is typically accompanied by external ophthalmoplegia. The patient may not complain of double vision if the ptosis occludes the visual axis. To understand the urgency, you must determine whether the pupil is involved.

    A pupil involving CN3 palsy is a true ophthalmic and neurosurgical emergency; this diagnosis cannot be missed and the patient must be referred for immediate neuroimaging with MRI/MRA or CT/CTA to characterize a potential aneurysm in the posterior communicating artery. 

    In contrast, a pupil sparing complete CN3 palsy is typically microvascular in nature in patients over 55, and these patients should be followed daily for a week to ensure that the pupil remains uninvolved.  

    Although a partial CN3 palsy may have a microvascular etiology, it may also represent an evolution of an expanding intracranial aneurysm, and therefore, this also requires immediate neuroimaging if the symptoms have been present for less than a week. 

    2. Horner’s Syndrome

    The classic presentation includes unilateral mild ptosis with anisocoria (smaller pupil on the ptotic side) due to involvement of the sympathetic chain. It’s imperative to document pupillary size and reactivity in light and dark conditions. In Horner’s syndrome you will find that the anisocoria will increase in dark conditions because the miotic pupil is unable to dilate due to sympathetic nerve damage. 

    Other key exam features include pupil dilation lag, “reverse ptosis” of the lower eyelid and, potentially, mydriasis. The most important history to obtain is pain, including headache, brow ache, forehead tingling and neck pain. Traditionally, pharmacologic testing was performed with apraclonidine, but regardless of this testing, almost all patients require neuroimaging: chest imaging with chest x-ray or CT with attention to the lung apices and MRI/MRA or CT/CTA of the head and neck. Imaging can typically be performed within days, but emergent imaging is required for a new onset Horner’s or in a patient complaining of headache or neck pain to rule out a carotid dissection. 

    3. Myasthenia Gravis

    The hallmark feature of myasthenia gravis is variability. Patients often report ptosis or diplopia worse toward the end of the day. It is important to elicit from the patient any weakness in proximal extremities, systemic medications, shortness of breath, dysphagia and history of autoimmune diseases. 

    A variety of tests are available to administer, including an in-office “rest test” or ice test; tensilon/edrophonium is less commonly utilized due to safety concerns; and laboratory work-up with acetylcholine receptor antibodies, including binding, blocking, and modulating antibodies. A chest CT can also be ordered to evaluate for a thymoma or thymic hyperplasia. Thyroid function tests should be done in all patients due to the high rate of concomitant dysfunction. 

    4. Chronic Progressive External Ophthalmoplegia

    The classic features of Chronic Progressive External Ophthalmoplegia (CPEO) are a slowly progressive ptosis and external ophthalmoplegia. In the early stages, the diagnosis may be clinically less obvious with asymmetry in its involvement, but as it progresses, the ptosis and ophthalmoplegia become so pronounced that it is less of a clinical challenge. 

    Since CPEO is a mitochondrial disorder, definitive diagnosis requires a muscle biopsy, but importantly, it can be associated with life threatening co-morbidities, most commonly cardiac in nature. Kearns Sayre Syndrome presents in younger patients with CPEO, pigmentary retinopathy, and cardiac disease, and prompt recognition of this condition is imperative due to the risk of sudden cardiac death.  

    5. Occult malignancy or infection

    A unilateral ptosis may also represent an outward sign of a malignancy or infectious process. A thorough evaluation, including eversion of the eyelid and examination of the conjunctiva and superior cul-de-sac, is needed. 

    It is also important to evaluate the patient for globe malposition in the case of an orbital process, in which case, orbital imaging may be warranted. Asymmetric globe position with a relatively proptotic or enophthalmic eye is an important sign to suggest associated orbital disease. In cases of thyroid eye disease, a droopy eyelid may actually represent the normal side with relative eyelid retraction on the contralateral eyelid, illustrating the concept of Hering’s law of equal innervation. In an older patient, lymphoma is high on the differential for a patient presenting with an orbital mass and unilateral ptosis. 

    In a busy ophthalmology practice, these patients may require more time than expected, but our hope is that these tips help you to quickly identify those patients that may need urgent referral to an oculoplastic surgeon or ER physician for further work-up. 

    The Academy’s YO Info Editorial Board is collaborating with YO leaders from our subspecialty society partners and thanks the young ophthalmologist committee of the American Society of Ophthalmic Plastic and Reconstructive Surgery (YASOPRS) for contributing to this article.

    Marie Somogyi, MD, and Alison Huggins Watson, MD About the author: Marie Somogyi, MD, is an oculofacial plastic surgeon in private practice in Austin, Texas. She also serves as affiliate faculty in the Department of Ophthalmology at the University of Texas at Austin. She serves as the young ophthalmologist committee chair of the American Society of Ophthalmic Plastic and Reconstructive Surgery (YASOPRS). Alison Huggins Watson, MD, is an oculofacial plastic surgeon in private practice in Philadelphia and also serves as faculty at Wills Eye Hospital. She is involved in both the Academy and ASOPRS.