Feline hyperthyroidism: diagnosis and treatment


Published: Dec 19, 2017
Keywords:
cat hyperthyroidism methimazole thyroxine
D. KASABALIS (Δ. ΚΑΣΑΜΠΑΛΗΣ)
N. SOUBASIS (Ν. ΣΟΥΜΠΑΣΗΣ)
T. A. PETANIDES (ΠΕΤΑΝΙΔΗΣ Θ.Α.)
Abstract

Hyperthyroidism is a common endocrinopathy in cats older than 8 years, with no sex or breed predisposition. Benign adenomas and adenomatous hyperplasia of the thyroid gland is observed in the majority of cases. Symptoms reflect the effect of thyroid hormone excess in various systems, with weight loss, polyphagia, polyuria-polydipsia, cardiovascular and gastrointestinal abnormalities being common clinical manifestations. On clinical examination, there is frequently prominent thyroid enlargement. Common laboratory abnormal findings include increased activity of alkaline phosphatase and alanino-aminotransferase, hyperphosphataemia, azotaemia and decreased concentration of ionized calcium and creatinine. Definite diagnosis of the disease is based on the demonstration of increased blood concentration of thyroid hormones.

Measurement of thyroxine concentration, alone or in conjunction with concentration of free thyroxine, is usually sufficient to reach a diagnosis. When diagnosis is uncertain, thyroid stimulating hormone, scintigraphy and dynamic function tests can be used. The possibility of concurrent diseases (e.g., renal failure, diabetes mellitus) must be investigated, as their presence has implications on diagnosis and treatment. Medical therapy, thyroidectomy, radionine therapy and low iodine diet are also valid options for treatment. Each has advantages and disadvantages that a clinician must take into consideration before instigating treatment. Prognosis for hyperthyroidism is favourable if no severe disease exists concurrently.

Article Details
  • Section
  • Review Articles
Downloads
Download data is not yet available.
References
Adams WH, Daniel GB, Legendre AM, Gompf RE, Grove CA (1997) Changes in renal function in cats following treatment of hyperthyroidism using 131I. Vet Radiol U ltrasound 38:231-238.
Archer FJ, Taylor SM (1996) Alkaline phosphatase bone isoenzyme and osteocalcin in the serum of hyperthyroid cats. Can Vet J 37:735-739.
Baral RM Peterson ME (2012) Hyperthyroidism. In: (ed: Little SE) The Cat: Clinical Medicine and Management. Saunders, St. Louis, pp. 571-592.
Barber PJ, Elliot J (1996) Study of calcium homeostasis in feline hyperthyroidism. J Small Anim Pract 37:575-582.
Becker TJ, Graves TK, Kruger JM, Braselton WE, Nachreiner RF (2000) Effects of methimazole on renal function in cats with hyperthyroidism. J Am Anim Hosp Assoc 36:215-223.
Berent AC, Drobatz KJ, Ziemer L, Johnson VS, Ward CR (2007) Liver function in cats with hyperthyroidism before and after 131 I therapy. J Vet Intern Med 21:1217-1223.
Blois SL, Dickie EL, Kruth SA, Allen DG (2010) Multiple endocrine disease in cats: 15 cases. J Feline Med Surg 12:637-642.
Bond BR, Fox RR, Peterson ME, Skavaril RV (1988) Echocardiographic findings in 103 cats with hyperthyroidism. J Am Vet Med Assoc 192:1546-1549.
Borreti FS, Sieber-Rucksthul NS, Gerber B, Laluha P, Baumgartnar C, Lutz H, Hofmann-Lehmann R, Reusch CE (2008) Thyroid enlargement and its relationship to clinicopathological parameters in suspected hyperthyroid cats. J Feline Med Surg 11:286-292.
Borreti FS, Sieber-Ruckstuhl NS, Schafer S, Baumgartner C, Riond B, Hofman-Lehman R, Reusch CE (2013) Duration of t4 suppression in hyperthyroid cats treated once and twice daily with transdermal methimazole. J Vet Intern Med 27:377 381.
Broussard JD, Peterson ME, Fox RR (1995) Changes in clinical and laboratory findings in cats with hyperthyroidism from 1983 to 1993. J Am Vet Med Assoc 206:302-305.
Bucknel DG (2000) Feline hyperthyroidism: spectrum of clinical presentations and response to carbimazole therapy. Aust Vet J 78:462-465.
Connolly DJ, Guitan J, Boswood A, Neiger R (2005) Serum troponin I levels in hyperthyroid cats before and after treatment with radioactive iodine. J Fel Med Surg 7:289-300.
Cook AK, Suchodolski JS, Steiner JM, Robertson JE. (2011) The prevelance of hypocobalinemia in cats with spontaneous hyperthyroidism. J Small Anim Pract 52:101-106.
Crenshaw KL, Peterson ME (1996) Pretreatment clinical and laboratory evaluation of cats with diabetes mellitus: 104 cases. J Am Vet Med Assoc 209:943-949.
Feldman EC, Nelson RW (2004) Canine and Feline Endocrinology and Reproduction, 3rd edn. Saunders, St Louis.
Ferguson DC, Freedman R (2006) Goiter in apparently euthyroid cats. In: (ed: August JR) Consultations in Feline Internal Medicine, 5th edn. Saunders, St. Louis, pp. 207-215.
Foster DJ, Thoday KL (2000) Tissue source of serum alkaline phosphatase in 34 hyperthyroid dogs: a qualitative and quantitative study. Res Vet Sci 68:89-94.
Fox PR, Peterson ME, Broussard JD (1999) Electrocardiographic and radiographic changes in cats with hyperthyroidism: comparison of populations evaluated during 1992-1993 vs. 1979-1982. J Am Anim Hosp Assoc 35:27-31.
Freeney DA, Anderson KL (2007) Nuclear imaging and radiation therapy in canine and feline thyroid disease. Vet Clin North Am Small Anim Pract 37:799-821.
Frenais R, Rosenberg D, Burgaud S, Horspool LJI (2009) Clinical efficacy of a once a day formulation of carbimazole in cats with hyperthyroidism. J Small Anim Pract 50:510-515.
Graham PA, Mooney CT, Murray M (1999) Serum fructosamine concentration in hyperthyroid cats. Res Vet Sci 67:171-175.
Graves TK (2010) Hyperthyroidism and the kidney. In (ed: August JR) Consultations in Feline Internal Medicine, 6th edn. Saunders, St. Louis, pp. 268-273.
Gunn-Moore D, Miller BJ (2006) The cat with weight loss and a good appetite. In: (ed: Rand J) Problem-Based Feline Medicine. Elsevier, Philadelphia, pp. 301-329.
Harvey AM, Hibbert A, Barret EL, Day MJ, Quiggin AV, Brannan RM, Caney SMA (2009) Scintigraphic findings in 120
hyperthyroid cats. J Feline Med Surg 11:96-106.
Henik RA, Stepien RL, Wenholz LJ, Dolson MK (2008) Efficacy of atenolol as a single antihypertensive agent in hyperthyroid cats. J Feline Med Surg 10:577-582.
Hoenig M (2012) Hyperthyroidism and diabetes mellitus In: (ed: Little SE) The Cat: Clinical Medicine and Management. Saunders, St. Louis, pp. 1101-1103.
Kobayashi DL, Peterson ME, Graves TK, Lesser M, Nichols CE (1990) Hypertension in cats with chronic renal failure or
hyperthyroidism. J Vet Intern Med 4:58-62.
Lurye JC (2006) U pdate on treatment of hyperthyroidism. In: (ed: August JR) Consultations in Feline Internal Medicine, 5th edn. Saunders, St. Louis, pp. 199-205.
Mayer-Roenne B, Goldstein RE, Erbis HN (2006) U rinary tract infections in cats with hyperthyroidism, diabetes mellitus and chronic kidney disease. J Feline Med Surg 9:124-132.
McLoughlin M, Di Bartola S, Birchard S, Day D (1993) Influence of systemic nonthyroidal illness on serum concentrations of thyroxine in hyperthyroid cats. J Am Anim Hosp Assoc 29:227-234.
Melendez LM, Yamka RM, Forrester SD Burris PA (2011) Titration of dietary iodine for reducing serum thyroxine concentrations in newly diagnosed hyperthyroid cats. J Vet Intern Med 25:683.
Menaut P, Connolly DJ, Volk A, Pace C, Luis Fuentes V, Elliot J, Syme H (2012) Circulating natriuretic peptide concentrations in hyperthyroid cats. J Small Anim Pract 53:673-678.
Milner RJ, Chanell CD, Levy JK, Schaer M (2006) Survival times for cats with hyperthyroidism treated with iodine 131, methimazole or both. J Am Vet Med Assoc 228:559-563.
Mooney CT, Little CJ, Macrae AW (1996) Effect of illness not associated with the thyroid gland on serum total and free thyroxine concentration in cats. J Am Vet Med Assoc 208:2004- 2008.
Mooney CT, Peterson ME (2004) Feline hyperthyroidism. In: (eds: Mooney CT, Peterson ME) BSAVA Manual of Canine and Feline Endocrinology, 3rd edn. Cambridge U niversity Press, Cambridge, pp 95-111.
Naan EC, Kirpenteinjh J, Kooistra HS, Peters ME (2006) Results of thyroidectomy in 101 cats with hyperthyroidism. Vet Surg 35:287-293.
Nemzek JA, Kruger JM, Walsaw R, Hauptman JG (1994) Acute onset of hypokalemia and muscular weakness in four hyperthyroid cats. J Am Vet Med Assoc 205:65-68.
Norsworthy GD, Adams VJ, McElhany MR, Milios JA (2002a) Palpable thyroid and parathyroid nodules in asymptomatic cats. J Feline Med Surg 4:145-151.
Norsworthy GD, Adams VJ, McElhany MR, Milios JA (2002b) Relationship between semi-quantative palpation and total thyroxine concentration in cats with and without hyperthyroidism. J Feline Med Surg 4:139-143.
Peterson ME (2013) Hyperthyroidism in cats. In: (ed: Rand J) Clinical Endocrinology of Companion Animals. Blackwell, Iowa, pp. 295-310.
Peterson ME, Graves TK, Cavanagh I (1987) Serum thyroid concentrations fluctuate in cats with hyperthyroidism. J Vet Intern Med 1:142-146.
Peterson ME, Kintzer PP, Cavanagh PG, Fox PR, Ferguson DC, Johnson GF, Becker DV (1983) Feline hyperthyroidism: pretreatment clinical and laboratory evaluation of 131 cases. J Am Vet Med Assoc 183:103-110.
Peterson ME, Kintzer PP, Hutvitz AI (1988) Methimazole treatment in 262 cats with hyperthyroidism. J Vet Intern Med 2:150-157.
Peterson ME, Melian C, Nichols R (2001) Measurement of serum concentrations of free thyroxine, total thyroxine and total triidothyronine in cats with hyperthyroidism and cats with nonthyroidal disease. J Am Vet Med Assoc 218:529-536.
Peterson ME, Ward CR (2007) Etiopathologic finings of hyperthyroidism in cats. Vet Clin North Am Small Anim Pract 37:633-645.
Philips DE, Radlinsky MG, Fiscer JR, Biller DS (2003) Cystic thyroid and parathyroid lesions in cats. J Am Anim Hosp Assoc 39:349-354.
Plantinga EA, Everts H, Kastelein AM, Beynen C (2005) Retrospective study of the survival of cats with acquired chronic renal unsufficiency offered different commercial diets. Vet Rec 157:185-187.
Randolf JF, De Marco J, Center SA, Kanthrowitz L, Crawford MA, Scarlett JM, Brooks M (2000) Prothrombin, activated partial thromboplastin and proteins induced by vitamin K absence or antagonists clotting times in 20 hyperthyroid cats before and after methimazole treatment. J Vet Intern Med 14:56-59.
Reusch CE, Schellenberg S (2010) Endocrine hypertension in small animals. Vet Clin North Am Small Anim Pract, 40:335-352.
Reusch CE, Tomsa K (1999) Serum fructosamine concentration in cats with overt hyperthyroidism. J Am Vet Med Assoc 215:1297- 1230.
Riensce MR, Graves TK, Scaeffer DJ (2008) An investigation of predictors of renal insyfficiency following treatment of
hyperthyroidism in cats. J Fel Med Surg 10:160-166.
Rishniw M, Thomas WP (2002) Dynamic right ventricular outflow tract obstruction: a new cause of systolic murmurs in cat. J Vet Intern Med 16:547-552.
Rutland BE, Nachreiner RF, Kruger JM (2009) Optimal testing for thyroid hormone concentration after treatment with methimazole in healthy and hyperthyroid cats. J Vet Intern Med 23:1025-1030.
Sartor LL, Trepanier LA, Kroll MM, Rodan I, Challoner L (2004) Efficacy and safety of transdermal methimazole in the treatment of cats with hyperthyroidism. J Vet Intern Med 18:651-655.
Shiel RE, Mooney CT (2007) Testing for hyperthyroidism in cats. Vet Clin North Am Small Anim Pract 37:671-691.
Slater MR, Geller S, Rogers K (2001) Long term health predictors of survival for hyperthyroid cats treated with iodine 131. J Vet Intern Med 15:47-51.
Syme HM (2007) Cardiovascular and renal manifestations of hyperthyroidism. Vet Clin North Am Small Anim Pract 37:723-743.
Thoday KL, Mooney CT (1992) Historical, clinical and laboratory features of 126 hyperthyroid cats. Vet Rec 131:257-264.
Tolbert K, Brown HM, Rakich PM, Radlinsky MA, Ward CR (2009) Dermoid cysts presenting as enlarged thyroid gland in a cat. J Feline Med Surg 11:717-719.
Trepanier LA (2007) Pharmacologic management of feline hyperthyroidism. Vet Clin North Am Small Anim Pract 37:775-788.
Trepanier LA, Hoffman SB, Kroll M, Rodan I, Challoner L (2003) Efficacy and safety of once versus twice daily administration of methimazole in cats with hyperthyroidism. J Am Vet Med Assoc 222:954-958.
Turrel JM, Feldman EC, Nelson RW, Cain GR (1988) Thyroid carcinoma causing hyperthyroidism in cats: 14 cases (1981-
. J Am Vet Med Assoc 193:359-364.
van Hoek I, Lefebvre HP, Peremans K, Meyer E, Croubels S, Vandermeulen E, Kooistra H, Saundres JH, Binst D, Daminet
S (2009a) Short- and long-term follow up of glomerular and tubular renal markers of kidney function in hyperthyroid cats after treatment with radioiodine. Domest Anim Endocrinol 36:45-56.
van Hoek I, Meyer E, Duchateau L, Peremans K, Smets P, Daminet S (2009b) Retinol binding protein in serum and urine of hyperthyroid cats before and after treatment with radionine. J Vet Intern Med 23:1031-1037.
Wakeling J, Moore K, Elliot J, Syme HM (2008) Diagnosis of hyperthyroidism in cats with mild chronic kidney disease. J Small Anim Pract 49:287-294.
Weiss DJ (2006) Aplastic anemia in cats-clinicopathological features and associated disease conditions 1996-2004. J Feline Med Surg 8:203-206.
Williams TL, Peak KJ, Brodbelt D, Elliot J, Syme HM (2010) Survival and development of azotemia after treatment of
hyperthyroid cats. J Vet Intern Med 24:863-869.
Yu S, Wedekind KJ, Burris PA, Forrester DS, Locniskar MF (2011) Controlled level of dietary iodine normalizes serum total thyroxine in cats with naturally occurring hyperthyroidism. J Vet Intern Med 25:683.
Most read articles by the same author(s)