Occurrence of Problems after Three Techniques of Bilateral Thyroidectomy in Cats

Abstract

Bilateral thyroidectomy was performed in 106 cats with hyperthyroidism by one of three techniques: original intracapsular, modified intracapsular, or modified extracapsular. Hypocalcemia was detected in the first 3 days after surgery in 11 (22%) of 50 cats treated by the intracapsular technique, 10 (33%) of 30 cats treated by the modified intracapsular technique, and 6 (23%) of 26 cats treated by the modified extracapsular technique. Hypocalcemia was classified as mild or severe. No signs of hypoparathyroidism developed in any of the 13 cats with mild hypocalcemia. Of the 14 cats with severe hypocalcemia, 8 had clinical signs of hypoparathyroidism before and during treatment with calcium and vitamin D, 3 were treated and no clinical signs developed, 2 were not treated but no clinical signs developed, and 1 was lost to follow-up. No cat required permanent calcium or vitamin D supplementation after surgery. Severe hypocalcemia and clinical signs of hypoparathyroidism occurred in 3 (6%) of the 50 cats treated by the intracapsular technique, 4 (13.3%) of the 30 cats treated by the modified intracapsular technique, and 1 (3.8%) of the 26 cats treated by the modified extracapsular technique. Twelve cats had recurrence of hyperthyroidism at a median time of 23 months. The intracapsular technique was used in 11 of these cats, and the modified extracapsular technique was used in 1. No clinical signs of hypothyroidism were detected in any of the cats. The modified intracapsular and modified extracapsular techniques of bilateral thyroidectomy are effective procedures for the treatment of feline hyperthyroidism.

PTH and ionized calcium evaluation in unilateral thyroidectomized cats

“…Recurrence of hyperthyroidism after thyroidectomy is caused by hypertrophy of adenomatous tissue left at the surgery site, presence of ectopic hyperfunctional thyroid tissue or hypertrophy of contralateral thyroid gland (Welches et al, 1989;Naan et al, 2006;Harvey et al, 2009). In this study, hyperthyroidism recurred in seven cats on day 7 and in four cats on sixth month suggesting that hypertrophy of contralateral thyroid gland led to relapse of disease.…”

Hypocalcemia and Primary Hypoparathyroidism

“…In hypocalcemic humans, disorders less common and less dramatic than tetany may be encountered, including (1) basal ganglia calcification and occasional extrapyramidal neurologic syndromes; (2) papilledema and increased intracranial pressure; (3) psychiatric disorders; (4) skin, hair, and fingernail abnormalities; (5) candidal infections; (6) inhibition of normal dental development; (7) lenticular cataracts; (8) intestinal malabsorption; and (9) increased serum concentrations of creatine phosphokinase and lactic dehydrogenase (Arnaud and Kolb, 1991;Wysolmerski and Insogna, 2012). In hypocalcemic humans, disorders less common and less dramatic than tetany may be encountered, including (1) basal ganglia calcification and occasional extrapyramidal neurologic syndromes; (2) papilledema and increased intracranial pressure; (3) psychiatric disorders; (4) skin, hair, and fingernail abnormalities; (5) candidal infections; (6) inhibition of normal dental development; (7) lenticular cataracts; (8) intestinal malabsorption; and (9) increased serum concentrations of creatine phosphokinase and lactic dehydrogenase (Arnaud and Kolb, 1991;Wysolmerski and Insogna, 2012).…”

“…to the actions of PTH at the level of both bone and kidney (Wysolmerski and Insogna, 2012). In conditions of severe magnesium deficiency, suppressed parathyroid secretion with concurrent hypocalcemia and hyperphosphatemia has been documented.…”

Management and monitoring of hyperthyroid cats: a survey of Australian veterinarians

“…Great concern (%) Cost of treatment 7 (1) 92 (17) 446 (82) Distance of travel to the radioiodine treatment facility 68 (13) 212 (39) 264 (49) Risk of radiation exposure 70 (13) 344 (63) 128 (24) Potential for development of side effects of the treatment 39 (7) 315 (58) 189 (35) Potential for development of co-morbid disease during 44 (8) 310 (57) (58) 81 (15) medications were the most frequently used treatment modality and twice daily carbimazole preferred by 49% of surveyed veterinarians. Surgical thyroidectomy was rarely performed.…”

“…12 Reported recurrence rates are 5 to 11% using various surgical techniques. 12,13 Anti-thyroid drugs can be an effective option but do not prevent progression of the underlying pathological process in the thyroid. 14,15 Therapeutic efficacy is also highly dependent on compliance with daily dosing.…”