Risk factors in patients with established Graves' Ophthalmopathy following Radioactive Iodine Therapy

Abstract

 

Purpose:

 

To assess the prevalence of risk factors in the development of Grave’s Ophthalmopathy (GO) in patients receiving radioactive Iodine therapy (RAI).

 

Methods:

 

Patients attending with an established diagnosis of GO were cross referenced with those who had undergone RAI therapy. A comparative control group of patients with GO but who had not received RAI therapy were also included. Ophthalmic (clinical activity score, exophthalmos, IOP, VA and ocular motility score (tropia and gaze limitation); Nuclear Medicine (RAI dosage) and Endocrine (thyroid function, medication) records were reviewed. Changes in recorded parameters were analysed before and following RAI.

 

Results:

 

29 patients with GO had received RAI treatment. Mean period of follow up 984 days (range: 6828 days), Mean age was 54 years with a F:M::24:5. 64.3% (18/29) were smokers and continued smoking post RAI. GO was present in 34.5% (10/29) of patients prior to RAI therapy and developed in 65.5% (19/29) following RAI. The median time to GO following RAI was 1166 days (range: 12,523 days). 79.3% (23/29) received no prophylactic course of oral prednisolone at the time of RAI therapy, 10.3% (3/29) of whom had pre-existing GO. 61% (18/29) of patient had at least one episode of hypothyroidism post RAI. Mean length of time in biochemical hypothyroid status was 144.5 days (range: 431 days). At the time of RAI therapy (and 3 months post), 13.8% (4/29) were referred for baseline ophthalmic review.There was very high variation in ophthalmic scores (table 1).

 

Conclusions:

 

RAI therapy carries a high risk for the development of GO. Better cross disciplinary liaison is needed to assist in detection and management of know risk factors for the development and progression of GO following RAI. In particular early ophthalmic recognition of GO, appropriate steroid prophylactic measures at the time of RAI therapy and prevention of post RAI hypothyroidism is needed.  

 

Keywords: clinical (human) or epidemiologic studies: risk factor assessment • radiation therapy