Hypothyreose – Auch für die Katzʼ?

Hypothyreose für den Hund, Hyperthyreose für die Katze. Ja, meistens. Doch manchmal sollte man auch bei Stubentigern mit unklarer Symptomatik an eine Hypothyreose denken.

Take Home

• Eine iatrogene Hypothyreose kann bei Thyreostatikagabe, nach Thyreoidektomie oder nach einer Radiojodtherapie auftreten.

• Mögliche klinische Symptome: Lethargie, ↑Gewicht trotz ↓Appetit, stumpfes Fell

• Zwei Drittel der betroffenen Katzen zeigen keine klinischen Symptome.

• Diagnostik:

  • Gesamt-T4 als alleiniger Parameter hat keine Aussagekraft, Interpretation muss immer im (klinischen) Kontext erfolgen.

  • Freies T4 sollte nicht als alleiniger Parameter genutzt werden.

  • Die Messung von Gesamt-T4 + fT4 besitzt die höchste Aussagekraft.

  • TSH kann als ergänzender Parameter (über das canine Assay) die diagnostische Sicherheit erhöhen.

• Literatur

• 1 Graham P. Measurement of feline thyrotropin using a commercial canine-specific immunoradiometric assay. J Vet Intern Med 2000; 14: 342
• 2 Fischetti AJ, Drost WT, Dibartola SP. et al. Effects of methimazole on thyroid gland uptake of 99 mTC-pertechnetate in 19 hyperthyroid cats. Vet Radiol Ultrasound 2005; 46: 267-272
• 3 Williams TL, Elliott J, Syme HM. Association of iatrogenic hypothyroidism with azotemia and reduced survival time in cats treated for hyperthyroidism. J Vet Intern Med 2010; 24: 1086-1092
• 4 Nykamp SG, Dykes NL, Zarfoss MK. et al. Association of the risk of development of hypothyroidism after iodine 131 treatment with the pretreatment pattern of sodium pertechnetate Tc 99 M uptake in the thyroid gland in cats with hyperthyroidism: 165 cases (1990–2002). J Am Vet Med Assoc 2005; 226: 1671-1675
• 5 Langston CE, Reine NJ. Hyperthyroidism and the kidney. Clin Tech Small Anim Pract 2006; 21: 17-21
• 6 Panciera DL, Lefebvre HP. Effect of experimental hypothyroidism on glomerular filtration rate and plasma creatinine concentrations in dogs. J Vet Intern Med 2009; 23: 1045-1050
• 7 Baral RM, Peterson ME. Thyroid gland disorders. In: Little SE. ed. The Cat: Clinical Medicine and Management. St. Louis, MO: Elsevier Saunders; 2012: 571-592
• 8 Tain YL, Hsu CN. Toxic dimethylarginines: Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA). Toxins (Basel) 2017; 9: 92
• 9 Braff J, Obare E, Yerramilli M. et al. Relationship between serum symmetric dimethylarginine concentration and glomerular filtration rate in cats. J Vet Intern Med 2014; 28: 1699-1701
• 10 Hall JA, Yerramilli M, Obare E. et al. Comparison of serum concentrations of symmetric dimethylarginine and creatinine as kidney function biomarkers in cats with chronic kidney disease. J Vet Intern Med 2014; 28: 1676-1683
• 11 Relford R, Robertson J, Clements C. Symmetric dimethylarginine: improving the diagnosis and staging of chronic kidney disease in small animals. Vet Clin North Am Small Anim Pract 2016; 46: 941-960
• 12 Hall JA, Yerramilli M, Obare E. et al. Comparison of serum concentrations of symmetric dimethylarginine and creatinine as kidney function biomarkers in healthy geriatric cats fed reduced protein foods enriched with fish oil, L-carnitine, and medium-chain triglycerides. Vet J 2014; 202: 588-596
• 13 Peterson ME, Castellano CA, Rishniw M. Evaluation of body weight, body condition, and muscle condition in cats with hyperthyroidism. J Vet Intern Med 2016; 30: 1780-1789
• 14 Relford R. Hyperthyroid cats: The IDEXX SDMA test is a more reliable indicator of kidney function than creatinine. Todays Vet Pract 2017; 7: 112-113
• 15 Peterson ME, Varela FV, Rishniw M. et al. Evaluation of serum symmetric dimethylarginine concentration as a marker for masked chronic kidney disease in cats with hyperthyroidism. J Vet Intern Med 2018; 32: 295-304
• 16 Peterson ME, Melian C, Nichols R. Measurement of serum concentrations of free thyroxine, total thyroxine, and total triiodothyronine in cats with hyperthyroidism and cats with nonthyroidal disease. J Am Vet Med Assoc 2001; 218: 529-536
• 17 Peterson ME, Guterl JN, Nichols R. Evaluation of serum thyreoid-stimulation hormone concentration as a diagnostic test for hyperthyreoidism in cats. J Vet Intern Med 2015; 29: 1327-1334
• 18 Wakeling J. Use of thyroid stimulating hormone (TSH) in cats. Can Vet J 2010; 51: 33-34