New developments in thyroid eye disease
Multidisciplinary approach improves chances of recovering binocularity in thyroid eye disease patients
David B Granet MD, MHCM,
FACS, FAAP, FAAO
Treating a patient with an immobile eye due to thyroid disease requires a multidisciplinary approach that takes into account the entire spectrum of the disease and its impact on the eye, reports David B Granet MD, MHCM, FACS, FAAP, FAAO, Shiley Eye Centre, University of California, San Diego, US.
“Thyroid disease may be difficult, but with careful planning and understanding and working with your colleagues in oculoplastics you can change these patients lives and make them smile again,” Dr Granet told the 2020 WSPOS Virtual Meeting.
The physician needs to understand the condition from the patient’s point of view. Often they will experience frustration because they don’t understand that they have to wait for the disease to get better and stabilised. Also confusing is the fact that the systemic effects of thyroid disease sometimes don’t become manifest until after they have developed the associated eye problems.
“Perhaps the first and foremost is the psychological impact of the disease; the disfigurement that we have is more impactful than the double vision, which is astonishing to people. So, if you don’t take care of the psychological burden then you are not helping your patients,” Dr Granet explained.
He noted that thyroid eye disease has two stages of development. There is the active inflammatory phase, which is characterised by sore, red eyes and cosmetic problems. It usually resolves within three years (many much sooner). However, 10% develop serious long-term ocular complications. Then there is the quiescent stage where a much less inflamed orbit and motility defect may be present. Severity at this stage may range from being a nuisance to blindness from exposure keratopathy or optic neuropathy.
There are also two different clinical spectrums of disease. Type I, where there is largely fat infiltration and associated proptosis and type II, where there is extraocular muscle involvement.
In 1997, Dr Granet and Don Kikkawa MD established the Thyroid Eye Center at UCSD, and they have developed a five-step approach to treating thyroid eye disease. The first step is medical treatment, the second is Botox, the third is orbital decompression, the fourth is strabismus repair and the fifth is lid repair.
He noted that research conducted by Dr Kikkawa at their centre has shown that it is possible to grade the amount of orbital decompression required based on the degree of proptosis present. In addition, they have shown that if you inject Botox at the time of decompression you can affect the strabismus and sometimes actually prevent strabismus.
Moreover, their research also shows that in correctly selected patients, outpatient administration of Botox chosen can correct small strabismus deviations, completely eliminating the need for strabismus surgery in up to one-third of cases, Dr Granet pointed out.
The goal in strabismus surgery is to get the patient to primary position and, if possible, reading position. It is possible to accomplish both by aiming just below the primary and allowing the patient to obtain a small chin-up position. Under-correcting the vertical alignment will help compensate for late changes and asymmetric surgery is needed in asymmetric problems.
“While most have inferior rectus contraction/over-action problems, many have superior rectus inferior oblique or even superior oblique type patterns. Look carefully, before you start,” he cautioned.
“Our group uses delayed adjustable sutures. Delaying the suture adjustment by five-to-seven days decreases risk of infection, decreases splinting and provides the patient with a better chance for binocular recovery.”
The introduction and FDA approval of the monoclonal antibody teprotumumab (Tepezza, Horizon Therapeutics) heralds a new era in the treatment of thyroid eye disease, Dr Granet noted.
“Don Kikkawa and I used to say that in the future thyroid eye disease will be stopped with medication and not the scalpel. The future has arrived,” he announced.
The human monoclonal antibody was approved for use in the United States in January 2020. It binds to the insulin-like growth factor 1 receptor (IGF-1R) and by doing so also inhibits thyroid stimulating hormone (TSH). In this way it inhibits the inflammatory cascade thereby reducing oedema and glycosaminoglycan production. It is administered intravenously at a dosage of 20mg/kg in eight cycles over 24 weeks, Dr Granet noted.
The FDA approved teprotumumab based on two randomised controlled studies showing meaningful reduction in proptosis in 71% and 83% of patients receiving the monoclonal antibody, compared to 20% and 10% of control patients.
Dr Granet presented two case studies from the UCSD oculoplastics team, Dr Kikkawa and Dr Bobby Korn, one with active disease and the other with chronic disease. In both cases, patients returned to their normal state after completing eight cycles of treatment.
“This is a game changer; however, there are side-effects and of course we have to pay attention to the teratogenicity of this in someone who might be pregnant. There may be relapses as well and it is expensive,” Dr Granet added.