Dog Thyroiditis: Occurrence and Similarity to Hashimoto’s Struma

Abstract

Histologically proved thyroiditis indistinguishable from human Hashimoto’s struma was found to occur in 12.5 % of 541 males and 10.9% of 440 females in a purebred beagle colony started in 1958. Most affected dogs descended from dog 461. The use of stud “I” more than doubled the prevalence. Among a noncolony purchased group of beagles in the same facilities, 4% of 336 males and 3% of 408 females had thyroiditis. We have studied 11 of the adult colony dogs, 11 purchased control adult dogs, 4 litters of the purebred colony and 16 control purebred beagle pups. Histologic involvement covering the entire gamut of Hashimoto’s struma seen in human thyroid glands was seenonly in the adult dogs of the purebred breeding colony. Only the 3 dogs with the most severe degree of thyroid histopathology showed a fall in the serum PBI values to <1.0 μg/100 ml on a low iodine diet, a subnormal 131I uptake, and a subnormal response of per cent thyroidal uptake of injected 131I to thyroid stimulating hormone. One dog with thyroiditis had thyroidal 131I dischargeable with KSCN. Tanned red blood cell serum antibody titers to beagle thyroglobulin were positive to titers as high as 1:512 but did not correlate with the occurrence or severity of thyroid histopathology. (Endocrinology83: 501, 1968)