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57 year old woman who complains "The lids are somewhat down"
Digital Journal of Ophthalmology 1997
Volume 3, Number 12
February 4, 1997
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| Differential Diagnosis | Blepharoptosis can be classified as being congenital or aquired, and further subclassified INTO myogenic, aponeurotic, neurogenic, neuromuscular junction, and mechanical etiologies. Levator dystrophy is the most common cause of congenital ptosis and aponeurotic defects are commonly implicated in aquired ptosis. Neurogenic etiologies include cranial nerve III palsy, Horner's syndrome, and aberrent regeneration. Myasthenia gravis is due to an abnormality at the neuromuscular junction, and is characterized by diurnal variation and variable symptoms. Mechanical ptosis may be secondary to eyelid lesions and cicatricial conjunctivitis. Lastly, one must consider pseudoptosis which is generally caused FROM orbital volume deficits such as with anophthalmia and phthisis bulbi, as well as with contralateral lid retraction.
Considering the history and examination findings, the differential was narrowed to myogenic ptosis and myasthenia gravis. Acquired myogenic ptosis includes myotonic dystrophy, chronic progressive external ophthalmoplegia, and oculopharyngeal dystrophy. Myotonic dystrophy is an autosomal dominant muscular dystropy with onset in the second decade of life, characterized by delayed relaxation of skeletal muscles after contraction. Symptoms include blepharospasm, which is followed by muscle atrophy, ptosis and weakness of orbicularis oculi. There are slow saccades and ophthalmoplegia often develops. The pupils are often miotic and sluggish to light and near. Characteristic Christmas tree cataracts (fine anterior and posterior subcapsular colored crystals) are found in virtually 100% of patients. There may be associated cardiac disease, dysphagia, constipation, incontinence, mental retardation, hyperostosis, scoliosis, testicular atrophy, and baldness.
Chronic progressive external ophthalmoplegia and the Kearns-Sayre syndrome are mitochondrial cytopathies characterized by adolescent onset bilateral asymmetric ptosis followed by progressive limitation of ocular motility, often with sparing of down-gaze. Examination findings often include slow saccades, nystagmus, and weak orbicularis oculi. In the Kearns-Sayre variant, there has been described pigmentary retinopathy, cardiac conduction abnormalities, ataxia, deafness, peripheral neuropathy, short stature, endocrine abnormalites including diabetes mellitus and hypogonadism, and elevated CSF protein. There are mitochondrial abnormalities on skeletal muscle biopsy, with ragged red fibers on Gomori's trichome stain and large irregular mitochondria with succinic dehydrogenase enzyme staining. Treatment includes coenzyme Q or ubidecarenone replacement to enhance mitochondrial respiration, which may improve cardiac function, ataxia, and exercise tolerance, but does not affect ophthalmplegia, ptosis, or retinopathy.
Oculopharyngeal dystrophy is an autosomal dominant muscular dystrophy that is most commonly found in French-Canadians with an onset of ptosis and dysphagia in the third or fourth decade. The dysphagia is due to weakness and lack of coordination of the muscles of the hypopharynx, resulting in an increased risk of aspiration pneumonia. There may also be some degree of ophthalmoplegia and weakness of the orbicularis, facial, and limb-girdle muscles. | |
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