Can Graves' Disease Cause Eustachian Tube Dysfunction?
Graves' disease itself does not directly cause eustachian tube dysfunction, but hypothyroidism—which can develop after treatment of Graves' disease—has been shown to cause eustachian tube dysfunction. Additionally, teprotumumab, a medication used to treat thyroid eye disease associated with Graves' disease, can cause eustachian tube dysfunction as an adverse effect.
The Hypothyroidism Connection
Hypothyroidism, not hyperthyroidism from Graves' disease, is associated with eustachian tube dysfunction. A study of 40 hypothyroid patients demonstrated statistically significant eustachian tube dysfunction compared to euthyroid controls (P < 0.01), with only 61.3% of hypothyroid patients having normal eustachian tube function before treatment 1. After achieving euthyroid status with levothyroxine treatment, eustachian tube function improved to 78.8%, with statistically significant increases in tympanometric pressure and compliance measurements (P < 0.05) 1.
Clinical Implications for Graves' Disease Patients
Graves' disease patients are at risk for developing hypothyroidism after radioactive iodine therapy or thyroidectomy, which occurs spontaneously in 5-20% of cases even without these treatments 2.
Maintaining euthyroidism is critical in Graves' disease patients, as both untreated hyperthyroidism and subsequent hypothyroidism can cause complications 3.
Hypothyroidism should be actively prevented after radioactive iodine treatment through early levothyroxine administration, typically starting at 2 weeks post-treatment 3.
Teprotumumab-Related Eustachian Tube Dysfunction
Teprotumumab, used for thyroid eye disease in Graves' patients, causes eustachian tube dysfunction in a significant proportion of patients. In a study of 32 patients treated with teprotumumab, 37.5% experienced eustachian tube dysfunction based on ETDQ-7 scores, and 15.6% developed symptoms of patulous eustachian tube with a median PHI-10 score of 15, indicating mild handicap 4.
Key Features of Teprotumumab-Related ETD
Onset is typically gradual, occurring around the sixth infusion (IQR 5-7) 4.
Symptoms are bilateral and persistent, with 93.8% of affected patients reporting that symptoms did not return to baseline 4.
Quality of life impact is substantial, with 87.5% of patients with hearing loss reporting it affected their quality of life, and 33.3% stating they would opt not to receive the medication again 4.
Common Pitfall to Avoid
Do not attribute eustachian tube dysfunction to active hyperthyroidism from Graves' disease. The evidence shows that hypothyroidism—not hyperthyroidism—causes eustachian tube dysfunction 1. If a Graves' disease patient presents with eustachian tube symptoms, check thyroid function tests to identify whether they have developed hypothyroidism, particularly if they have received radioactive iodine or undergone thyroidectomy 3, 2.