Effective management of thyroid eye disease

May 1, 2008

Management of thyroid eye diseases should be individualized to the severity of signs and symptoms of each patient and based as well on whether the disease is in an active or quiescent phase. Some corrective procedures should be postponed for months or years until the disease no longer is active.

Baltimore

-Thyroid eye disease typically follows a pattern of active disease, a plateau, and a quiescent or stable period. Medical and surgical management likewise should be performed in a sequence that matches these phases and the patient's particular manifestations of the disease, according to

Shannath Merbs, MD, PhD, FACS

. She outlined management strategies for thyroid eye disease in a talk at the Current Concepts in Ophthalmology meeting here.

During the active phase of the disease, management activities should be directed at preserving sight through therapies such as lubrication with artificial tears or ointments for corneal exposure, and corticosteroids, orbital surgery, or radiation for optic neuropathy.

Once the disease has stabilized, a process that generally requires at least 6 months, the clinician can correct lingering effects of the condition such as exophthalmos, double vision, and eyelid retraction, said Dr. Merbs, an associate professor of ophthalmology and oncology, reconstructive and cosmetic oculoplastic surgery division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.

Thyroid eye disease also is known as thyroid-related orbitopathy (TRO). An autoimmune disorder, TRO usually, but not always, is associated with clinically evident thyroid dysfunction, according to Dr. Merbs. Patients usually have a thyroid-stimulating hormone receptor (TSH-R) autoantibody, the target of which is thought to be orbital fibroblasts rather than myocytes, which lack significant TSH-R.

TRO is associated to varying degrees with other thyroid disorders, Dr. Merbs said. Of patients whose initial presentation is to an endocrinologist for hyperthyroidism, about 25% will have TRO. In contrast, of patients whose initial presentation is to an ophthalmologist for TRO, autoimmune hyperthyroidism or Graves' disease is diagnosed in about 90%. Hashimoto's thyroiditis, an autoimmune hypothyroidism, is diagnosed in about 5% of patients, and another 5% are euthyroid, having no clinically detectable form of thyroid dysfunction.

The risk factors for developing TRO or exacerbating an existing condition include being female and having a history of smoking. "Patients always ask me what they can do to prevent their eyes from getting worse, but really the only thing they have control over is smoking and stabilizing their thyroid function tests," Dr. Merbs said.

Another risk factor is undergoing radioactive iodine therapy of the thyroid gland, which can put patients in a difficult position. "A lot of patients are not treated definitely with radioactive iodine because of this fear," Dr. Merbs said. "If you have a patient with thyroid eye disease and thyroid ablation is planned, suggest to the endocrinologist [that he or she try] steroid prophylaxis."

Defining TRO

Dr. Merbs also described the clinical findings, symptoms, and signs of TRO. Clinically, the disease typically is marked by an active phase of increasing activity and severity, followed by a plateau and then a phase of decreasing activity. Symptoms include tearing, burning, swelling, and pressure or a tight sensation in the orbit, presumably caused by enlarged tissues. The most characteristic sign of TRO is upper eyelid retraction. Other signs include chemosis, proptosis, restrictive ophthalmoplegia, and compressive optic neuropathy.

In addition to conducting a standard ophthalmologic exam when TRO is suspected, clinicians should evaluate color vision and perform visual field testing to rule out an optic neuropathy. Blood tests that may be useful include thyroid-stimulating hormone (TSH), triiodothyronine, thyroxine, and TSH-R antibodies. If a patient with TRO is initially euthyroid, these tests should be repeated every 3 to 4 months for a year or two because these patients often go on to develop hyper- or hypothyroidism, Dr. Merbs said.

Ultrasound imaging is a valuable imaging tool, although it is not always readily available to the general ophthalmologist, she added. CT scanning will be more accessible to many clinicians and is particularly helpful at assessing posterior compression of the optic nerve.

Compressive optic neuropathy from TRO warrants acute intervention, consisting of 1 g/day methylprednisolone for 3 days followed by 1 to 2 mg/kg/day of prednisone orally. If steroid therapy does not improve the condition, it may at least prevent it from worsening until further treatment can be administered, Dr. Merbs said. The definitive treatment for a compressive optic neuropathy is posterior decompression, which can be performed through a medial orbital approach or endoscopically.

Treatment options

Suggested forms of treatment for corneal exposure include lubrication and moisture chambers. Dr. Merbs recommends that patients use a circle of plastic wrap secured with a ring of petroleum jelly around the eye as a means of accomplishing a nighttime moisture chamber without causing dermatitis from repeated tape use. Tarsorrhaphy can be performed if needed.

Steroid treatment should be approached cautiously in patients with considerable swelling and redness. If used, a recommended dose is 1.5 mg/kg/day, with a follow-up exam in 7 to 10 days; the dose should be tapered over a period of 6 weeks. Low-dose radiotherapy is another option, although it is controversial and usually is reserved for patients with active TRO, Dr. Merbs said.

Non-emergent surgery is effective for improving exophthalmos or correcting strabismus or lid malpositions, she said. According to Dr. Merbs, particularly strabismus and eyelid surgery usually are delayed until the patient is euthyroid and the condition has been stable for at least 6 months. If an orbital decompression is needed, it should be the first surgical procedure and can be a two- or three-walled bony decompression with a fat decompression, depending on the amount of exophthalmos.

"There is a very particular sequence to the surgical repair of the eye manifestations of thyroid disease. You want to treat patients medically, and you want to make sure that you don't miss the compressive optic neuropathy because you can temporize that with oral steroids or IV steroids in most cases, prior to being able to perform a posterior decompression," Dr. Merbs said. "If you have a patient whose condition] is stable, who does not have compressive optic neuropathy, then the first surgery you would do, if needed, would be decompression surgery."

The next steps would be strabismus surgery and then lid surgery, such as a levator recession for upper eyelid retraction, if needed. She added that patients' conditions should be stable before surgery, with them having completed a 6-month period with no medication changes, normal blood tests, and no change in appearance as documented by photography.

Not every patient will require every medical approach or surgical procedure, and an individualized treatment plan should be drawn up for each person based on the severity of signs and symptoms and the phase of disease, she concluded. The Current Concepts meeting was held at Johns Hopkins University and was co-sponsored by Ophthalmology Times.OT