Lucy J M, Peterson M E, Randolph J F, Scrivani P V, Rishniw M, Davignon D L, Thompson M S, Scarlett J M
Departments of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY.
Animal Endocrine Clinic, New York, NY.
J Vet Intern Med. 2017 Mar;31(2):326-334. doi: 10.1111/jvim.14646. Epub 2017 Feb 3.
Radioiodine ( I) is effective treatment for hyperthyroidism in cats, but optimal dose to restore euthyroidism without inducing hypothyroidism is unclear. Treatment-induced hypothyroidism can lead to azotemia and reduced duration of survival.
To compare efficacy and short-term outcomes of low-dose I versus higher, standard-dose I as treatment for hyperthyroidism.
A total of 189 client-owned cats undergoing I treatment for mild-to-moderate hyperthyroidism (serum T ≥ 4.0 μg/dL and <13.0 μg/dL).
Prospective, nonrandomized, cohort study comparing treatment with either low-dose (2 mCi, n = 150) or standard-dose (4 mCi, n = 39) I. Serum T , thyroid-stimulating hormone (TSH), and creatinine concentrations were measured after 1, 3, and 6 months to determine persistent hyperthyroidism, overt hypothyroidism (low T , high TSH), subclinical hypothyroidism (normal T , high TSH), and azotemia.
There was no significant difference in prevalence of cats with persistent hyperthyroidism between standard- and low-dose treatment groups at 3 (0% versus 5.3%; P = .34) and 6 (0% versus 3.3%; P = .51) months. Overt (18% versus 1%; P = .0005) or subclinical (46% versus 21%; P = .004) hypothyroidism was more common in cats at 6 months after standard-dose I. No difference in incidence of azotemia existed between groups, but cats treated with standard-dose I had higher creatinine concentrations (P < .05) and higher percent rises in creatinine (P < .0001).
Low-dose I is safe and effective for cats with mild-to-moderate hyperthyroidism, as evidenced by a cure rate of >95% with reduced frequency of iatrogenic hypothyroidism and azotemia.
放射性碘（I）是治疗猫甲状腺功能亢进的有效方法，但恢复甲状腺功能正常而不引起甲状腺功能减退的最佳剂量尚不清楚。治疗引起的甲状腺功能减退可导致氮血症和生存时间缩短。
比较低剂量I与较高的标准剂量I治疗甲状腺功能亢进的疗效和短期结果。
共有189只接受I治疗轻度至中度甲状腺功能亢进（血清T≥4.0μg/dL且<13.0μg/dL）的客户拥有的猫。
前瞻性、非随机队列研究，比较低剂量（2mCi，n = 150）或标准剂量（4mCi，n = 39）I的治疗。在1、3和6个月后测量血清T、促甲状腺激素（TSH）和肌酐浓度，以确定持续性甲状腺功能亢进、显性甲状腺功能减退（低T、高TSH）、亚临床甲状腺功能减退（正常T、高TSH）和氮血症。
标准剂量组和低剂量组在3个月（0%对5.3%；P = 0.34）和6个月（0%对3.3%；P = 0.51）时持续性甲状腺功能亢进猫的患病率无显著差异。标准剂量I治疗6个月后的猫中，显性（1八对1%；P = 0.0005）或亚临床（46%对21%；P = 0.004）甲状腺功能减退更为常见。两组间氮血症发生率无差异，但标准剂量I治疗的猫肌酐浓度较高（P < 0.05），肌酐升高百分比也较高（P < 0.0001）。
低剂量I对轻度至中度甲状腺功能亢进的猫安全有效，治愈率>95%，医源性甲状腺功能减退和氮血症的发生率降低证明了这一点。
