Menzies-Gow Nicola J
Department of Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK.
Vet Sci. 2025 Aug 20;12(8):780. doi: 10.3390/vetsci12080780.
Pituitary pars intermedia dysfunction (PPID) is a common, slowly progressive, neurodegenerative disorder of the older horse. Oxidative damage to the hypothalamic periventricular neurons results in loss of dopaminergic inhibition of the pars intermedia region of the pituitary gland. Consequently, there is increased production of the pro-opiomelanocortin (POMC)-derived hormones normally produced by this region, as well as initial melanocyte hypertrophy and hyperplasia, followed by adenomatous change. Clinical signs that are highly suggestive of the disease are generalised and regional hypertrichosis and delayed/abnormal coat shedding. Numerous clinical signs provide a moderate clinical suspicion, including hyperhidrosis, abnormal fat distribution/regional adiposity, epaxial muscle atrophy/loss of topline, laminitis, weight loss, recurrent infections, behavioural changes/lethargy, polyuria and polydipsia, a pot-bellied appearance, bulging supraorbital fat pads, reduced wound healing, lordosis and infertility. In all animals, a diagnosis of PPID is made based on the signalment, clinical signs and results of further diagnostic tests, with age being a crucial factor to consider. Currently recommended further diagnostic tests are measurement of basal adrenocorticotrophic hormone (ACTH) concentrations (all year) and evaluation of the ACTH response to thyrotrophin-releasing hormone (TRH) using seasonally adjusted references intervals (non-autumn). Animals should also be tested for insulin dysregulation, as laminitis risk in PPID is associated with hyperinsulinaemia. PPID can be managed but not cured; it is a lifelong condition. The individual clinical signs can be managed, e.g., clipping the excessive haircoat and providing unrestricted access to water for individuals with polydipsia. Alternatively, pharmacological management can be employed, and the dopamine-2 receptor agonist pergolide is licensed/approved for the treatment of equine PPID. This should be prescribed in combination with dietary recommendations based on the body condition score and insulin sensitivity status of the individual animal.
垂体中间叶功能障碍（PPID）是老年马匹常见的、缓慢进展的神经退行性疾病。下丘脑室周神经元的氧化损伤导致对垂体中间叶区域多巴胺能抑制作用丧失。因此，该区域正常产生的促肾上腺皮质激素原（POMC）衍生激素产量增加，同时最初出现黑素细胞肥大和增生，随后发生腺瘤样改变。高度提示该病的临床症状为全身性和局部性多毛症以及被毛脱落延迟/异常。众多临床症状提示中度临床怀疑，包括多汗、脂肪分布异常/局部肥胖、背侧肌肉萎缩/背线消失、蹄叶炎、体重减轻、反复感染、行为改变/嗜睡、多尿和多饮、大腹便便的外观、眶上脂肪垫突出、伤口愈合减慢、脊柱前凸和不育。在所有动物中，PPID的诊断基于病史、临床症状和进一步诊断测试的结果，年龄是一个关键的考虑因素。目前推荐的进一步诊断测试是全年测量基础促肾上腺皮质激素（ACTH）浓度，并使用季节性调整的参考区间（非秋季）评估ACTH对促甲状腺激素释放激素（TRH）的反应。还应检测动物是否存在胰岛素调节异常，因为PPID中的蹄叶炎风险与高胰岛素血症有关。PPID可以得到控制但无法治愈；它是一种终身疾病。个体临床症状可以得到控制，例如，剪掉过多的被毛，为多饮的个体提供不受限制的饮水。或者，可以采用药物治疗，多巴胺-2受体激动剂培高利特已获许可/批准用于治疗马的PPID。应根据个体动物的体况评分和胰岛素敏感性状况，结合饮食建议开出处方。
