Hyperthyroidism and hypothyroidism in patients with autoimmune pancreatitis.

Objective: The objective of this study is to clarify the clinical features of thyroid dysfunction observed in patients with autoimmune pancreatitis (AIP).

Methods: We repeatedly examined thyroid function in 74 patients with type 1 AIP (58 males, 16 females; average onset age of AIP 67 years). Clinical and serological findings in patients with thyroid dysfunction were analyzed.

Results: During follow-up, clinical and subclinical hypothyroidism were observed in 3 and 17 patients, respectively. Clinical and subclinical hyperthyroidism were observed in 5 and 1 patients, respectively. One patient showed clinical hyperthyroidism followed by subclinical hypothyroidism. All patients with clinical and subclinical hypothyroidism were asymptomatic and required no medical treatment, whereas four patients with clinical hyperthyroidism were symptomatic and received treatment with thiamazole.

Conclusion: Frequent hypothyroidism in AIP, which was previously reported, was confirmed. Moreover, in this study, the association between hyperthyroidism and AIP was demonstrated. Hyperthyroidism in AIP may be more clinically significant than hypothyroidism because patients frequently require medical treatment.