We report a two-month-old male cat weighing 630 grams with congenital hypothyroidism. The main complaints were difficulty defecating for more than three days and prostration. Physical examination revealed a broad, flat face, a short neck, enlarged submandibular lymph nodes, chemosis, mild bilateral mucopurulent ocular discharge, seborrheic coat, with gingival thickening around the upper and lower deciduous incisor teeth with partial eruption. The abdomen was distended due to constipation and right unilateral cryptorchidism. Based on this, feline congenital hypothyroidism was suspected. Hormonal tests (free T4 by equilibrium dialysis of 0.06 ng/dl, total T4 of 0.1 ng/ml and TSH of 4.7 ng/ml) confirmed this. Treatment was started with levothyroxine sodium (5-32.2 µg/kg/day). After 120 days of treatment, there was clinical stabilization. Then the patient underwent orchiectomy of the left and of the right ectopic testicles, and at 380 days of treatment, the thyroid scintigraphy showed intense uptake of the radiopharmaceutical by both thyroid lobes and a significant increase in volume. Clinical evaluation showed weight gain (2.6 kilograms during treatment), improvement in the shape of the skull, and a notable increase in body size. At 17 months of age, hormone values were within the reference limits after administration of levothyroxine sodium (32.2µg/kg/day).
Bojanić, K., Acke, E., & Jones, B. R. (2011). Congenital hypothyroidism of dogs and cats: A review. New Zealand Veterinary Journal, 59(3), 115-122. http://dx.doi.org/10.1080/00480169.2011.567964. PMid:21541884.
Broome, M. R. (2006). Thyroid scintigraphy in hyperthyroidism. Clinical Techniques in Small Animal Practice, 21(1), 10-16. http://dx.doi.org/10.1053/j.ctsap.2005.12.002. PMid:16584025.
Crowe, A. (2004). Congenital hypothyroidism in a cat. The Canadian Veterinary Journal, 45(2), 168-170. PMid:15025157.
Feeney, D. A., & Anderson, K. L. (2007). Nuclear imaging and radiotherapy in canine and feline thyroid disease. The Veterinary Clinics of North America: Small Animal Practice, 37(4), 799-821. http://dx.doi.org/10.1016/j.cvsm.2007.03.005. PMid:17619013.
Feldman, E. C., Fracassi, F., & Peterson, M. E. (2021). Fundamentals of feline endocrinology. MedVet.
Galgano, M., Spalla, I., Callegari, C., Patruno, M., Auriemma, E., Zanna, G., Ferro, S., & Zini, E. (2014). Primary hypothyroidism and thyroid goiter in an adult cat. Journal of Veterinary Internal Medicine, 28(2), 682-686. http://dx.doi.org/10.1111/jvim.12283. PMid:24417675.
Geronimo, A. A., Schmidt, R. B., & Salvi, J. O. (2018). Pharmacological aspects of levothyroxine sodium: A brief review. Brazilian Journal of Surgery and Clinical Research, 23(2), 128-134. https://www.mastereditora.com. br/periodico/20180704_092837.pdf
Golinelli, S., Tardo, A. M., Vecchiato, C. G., Guido, E. A., Perfetti, S., Diana, A., & Fracassi, F. (2022). Evaluation of weight gain, clinicopathological and radiographic changes after early diagnosis and treatment of congenital hypothyroidism in cats. Veterinary Sciences, 9(3), 140. http://dx.doi.org/10.3390/vetsci9030140. PMid:35324868.
Greco, D. S. (2006). Diagnosis of congenital and adult-onset hypothyreoidism in cats. Clinical Techniques in Small Animal Practice, 21(1), 40-44. http://dx.doi.org/10.1053/j.ctsap.2005.12.007. PMid:16584030.
Jacobson, T., & Rochette, J. (2018). Congenital feline hypothyroidism with partially erupted adult dentition in a 10-month-old male neutered domestic shorthair cat: A case report. Journal of Veterinary Dentistry, 35(3), 178-186. http://dx.doi.org/10.1177/0898756418785946. PMid:30168381.
Peterson, M. E. (2015). Primary goitrous hypothyroidism in a young adult domestic longhair cat: Diagnosis and treatment monitoring. Journal of Feline Medicine and Surgery Open Reports, 1(2), 2055116915615153. http:// dx.doi.org/10.1177/2055116915615153. PMid:28491394.
Peterson, M. E., & Rishniw, M. (2021). A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism. Journal of Veterinary Internal Medicine, 35(5), 2140-2151. http://dx.doi.org/10.1111/jvim.16228. PMid:34351027.
Peterson, M. E., Broome, M. R., & Rishniw, M. (2016). Prevalence and degree of thy-roid pathology in hyperthyroid cats increases with disease duration: Across-sectional analysis of 2096 cats referred for radioiodine therapy. Journal of Feline Medicine and Surgery, 18(2), 92-103. http://dx.doi.org/10.1177/1098612X15572416. PMid:25673019.
Peterson, M. E., Carothers, M. A., Gamble, D. A., & Rishniw, M. (2018). Spontaneous primary hypothyroidism in 7 adult cats. Journal of Veterinary Internal Medicine, 32(6), 1864-1873. http://dx.doi.org/10.1111/jvim.15239. PMid:30294940.
Peterson, M. E., Melián, C., & Nichols, R. (2001). Measurement of serum concentrations of free thyroxine, total thyroxine, and total triiodothyronine in cats with hyperthyroidism and cats with nonthyroidal disease. Journal of the American Veterinary Medical Association, 218(4), 529-536. http://dx.doi.org/10.2460/javma.2001.218.529. PMid:11229503.
Quante, S., Fracassi, F., Gorgas, D., Kircher, P. R., Boretti, F. S., Ohlerth, S., & Reusch, C. E. (2010). Congenital hypothyroidism in a kitten resulting in decreased IGF-I concentration and abnormal liver function tests. Journal of Feline Medicine and Surgery, 12(6), 487-490. http://dx.doi.org/10.1016/j.jfms.2010.01.013. PMid:20223692.
Sjollema, B. E., den Hartog, M. T., Vijlder, J. J., van Dijk, J. E., & Rijnberk, A. (1991). Congenital hypothyroidism in 2 cats due to defective organification – data suggesting loosely anchored thyroperoxidase. Acta Endocrinologica, 125(4), 435-440. http://dx.doi.org/10.1530/acta.0.1250435. PMid:1659766.
Stolf, L.C. & Martins, G.C. (2016). Feline congenital hypothyroidism: a case report. Revista Científica de Medicina Veterinária - Pequenos Animais e Animais de Estimação, 12(45), 1-7.
Tanase, H., Kudo, K., Horikoshi, H., Mizushima, H., Okazaki, T., & Ogata, E. (1991). Inherited primary hypothyroidism with thyrotrophin resistance in Japanese cats. The Journal of Endocrinology, 129(2), 245-251. http://dx.doi. org/10.1677/joe.0.1290245. PMid:1904088.
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