Laboratory Studies
If myasthenia gravis is suspected in a patient with ptosis, perform a serum assay for acetylcholine receptor antibodies and antistriated muscle antibody. Muscle-specific tyrosine kinase (MUSK) levels can be obtained when acetylcholine receptor antibodies levels are negative and the suspicion for generalized myasthenia is high.
The ice test has been shown to improve ptosis in patients with myasthenia. [5]
An edrophonium chloride (Tensilon) test or single-fiber electromyography may be needed to definitely exclude the diagnosis.
CSF analysis can aid in the diagnosis of multiple sclerosis. Mild lymphocytosis or increased protein levels in the CSF levels may be present. In addition, elevated immunoglobulin G (IgG) levels and oligoclonal bands often are found.
In patients with chronic progressive external ophthalmoplegia, an electrocardiogram, electroretinogram, electromyography, and mitochondrial assay should be considered.
Patients with suspected thyroid abnormalities should undergo thyroid function studies.
Imaging Studies
If ptosis is present with other neurologic deficits, imaging of the brain, orbits, or cerebrovascular system should be performed. An emergent CT angiography of the brain is necessary when ptosis is accompanied by other signs of a third nerve palsy. MRI of the brain with and without gadolinium is the imaging modality of choice to exclude structural cerebral etiologies, including middle cranial fossa neoplasia and demyelinating disorders.
CT scanning without contrast can be used to exclude dysthyroid orbitopathy and intraorbital neoplasia.
In acquired Horner syndrome, MRI or CT scan of the brain, MRA of neck, CT scan or X-ray of the spine, and CT scan or X-ray of the chest (especially of the apex of the lung) are needed to exclude a structural lesion along the sympathetic pathway.
Other Tests
Sympathomimetic agents can be used to stimulate the Mueller muscle, as follows:
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2.5% phenylephrine
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0.5% apraclonidine (Iopidine)
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1.0% apraclonidine (Iopidine)
Ten percent phenylephrine has not be shown to have increased clinical efficacy in predicting the outcome of Muller muscle–conjunctival resection. Therefore, the authors do not feel the use of 10% phenylephrine is necessary. [6]
Instill 2 drops on the eye under the eyelid (have the patient look down), wait 5 minutes, and assess any change in the palpebral fissure and the marginal reflex distance. If no response is observed or if elevation is not adequate, external levator resection or advancement may be needed to correct the ptosis. If a good response is observed, the ptosis can be repaired by advancing the internal levator (Mueller muscle–conjunctival resection).
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Patient with bilateral ptosis before surgery. Note the high lid creases.
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Same patient as in the previous image after bilateral internal levator advancement. No skin incision was made, and no crease reformation was performed.
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Anterior approach to the levator. White band is the levator aponeurosis (arrow).
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Left ptosis. Lid crease is absent on the left. The crease is up in the sulcus. Superior sulcus deformity is present on the left and right, and the patient is elevating her brows. The right upper lid should be checked for an underlying or masked ptosis. If the right lid is ptotic, lifting the left lid causes the right lid to droop.
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Visual field shows functional blockage of superior visual field due to a ptotic lid. Hashed line represents the superior extent of the seen visual field with the lid lifted. Solid line is with the lid in its natural, ptotic position.
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Congenital ptosis on right. Note the presence of a lid crease.
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Glasses with a crutch attached (arrow) that can be used to lift the lid if the patient does not desire surgery.
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Patient with myasthenia gravis. Right lid is more ptotic than the left lid.
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Same patient as in the previous image, 3 months later. Note how the ptosis has changed and is more on the left than the right.
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Patient with bilateral ptosis before surgery.
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Same patient as in the previous image after internal levator advancement. Patient has excessive skin (dermatochalasia) after the lid was lifted, with a pseudoptotic effect more on the left than the right. The dermatochalasia was present before surgery but is more significant afterward. Patient also has brow ptosis.
