Severe hypertriglyceridaemia in horses and ponies with endocrine disorders

Abstract

SummaryReasons for performing the study: Severe hypertriglyceridaemia in horses and ponies with endocrine disorders has been reported anecdotally but has not been documented in the literature. Objectives: To describe historical and clinicopathological findings as well as progression and outcome in horses and ponies with severe hypertriglyceridaemia (serum triglyceride concentration >5.65 mmol/l) secondary to an endocrine disorder that were otherwise apparently healthy. Methods: Cases from 6 participating institutions were identified and case details extracted from the medical records. Results: Case details of 3 horses and 4 ponies were available. Presenting complaints included weight loss despite good appetite in 4 animals, while in 3 hypertriglyceridaemia was identified incidentally. All animals were bright and alert and showed a normal or increased appetite. Serum triglyceride concentrations ranged from 10.5 to 60.3 mmol/l. Other abnormalities included hyperglycaemia in 6 animals, suspected insulin resistance and mild to severe increases in hepatic enzyme activities. In 2 animals, moderate hepatic lipidosis was confirmed histologically. Three horses and 3 ponies were diagnosed with pituitary pars intermedia dysfunction based on clinical signs and basal adrenocorticotropic hormone (ACTH) concentrations or dexamethasone suppression test results. In 5 of these, type 2 diabetes mellitus was also confirmed, while one pony suffered from type 2 diabetes mellitus without concurrent pituitary pars intermedia dysfunction. Laboratory abnormalities improved in 4 animals with treatment (pergolide and/or insulin), in one horse specific treatment was not attempted, and in 2 ponies treatment was impaired by the owner or only partly effective. In one of the latter cases, biochemical abnormalities persisted for 7 years without apparent ill effects. Conclusions and potential relevance: Horses and ponies may develop severe hypertriglyceridaemia secondary to endocrine disorders that are associated with insulin resistance. Hypertriglyceridaemia can resolve with treatment of the endocrinopathy. Although biochemical evidence of hepatic compromise was present, clinical abnormalities were not noted in these animals.

Analysis of the correlation between lipotoxicity and pituitary-thyroid axis hormone levels in men and male rats

“…The reason for the difference between humans and rats unclear, though: Dunkel et al . [25] reported that hypertriglyceridemia progressively reduced basal ACTH levels in horses. Given that the effect of lipotoxicity on hormone levels is progressive, the duration of the HF diet may be not enough to affect these hormone concentrations.…”

Current best practice in clinical management of equine endocrine patients

“…Hypertriglyceridaemia is also a concern when horses enter negative energy balance, as occurs with colic, dental disease or systemic illness. Dunkel et al (2013) describe this problem in their recent retrospective study of hospitalised horses and ponies. Of the 7 animals identified with endocrine disorders and hypertriglyceridaemia (serum triglyceride concentration >5.65 mmol/l), 3 horses and 3 ponies were diagnosed with PPID and 5 had concurrent type 2 diabetes mellitus.…”

“…; Dunkel et al . ). In contrast, some of the common endocrinopathies of human patients, dogs and cats such as Addison's disease, hyperthyroidism and hypothyroidism, are rarely seen in horses.…”

“…There appears to be a genetic basis to ID, with certain breeds of horse, including ponies, Morgan horses and Arabians being overrepresented. Other endocrine disorders of horses include hyperparathyroidism, as discussed by Axiak and Johnson (2012) in their article focused on paraneoplastic syndromes, and diabetes mellitus (Durham et al 2009;Dunkel et al 2013). In contrast, some of the common endocrinopathies of human patients, dogs and cats such as Addison's disease, hyperthyroidism and hypothyroidism, are rarely seen in horses.…”

Suspected case of hypersplenism as a cause of anaemia, thrombocytopenia and leucopenia in a Miniature Horse gelding

“…Additional features of this case included persistent hypertriglyceridaemia despite a good appetite and uncontrolled PPID. Hypertriglyceridaemia has been reported secondary to endocrine disorders, including PPID, and is associated with hyperglycaemia and insulin resistance (Dunkel et al 2014). It is possible that the use of corticosteroids in a horse with PPID exacerbated glucose and energy dysregulation.…”