The successful long-term treatment of a horse in Sweden with central diabetes insipidus has been reported in the Journal of Veterinary Internal Medicine.
The four‐year‐old gelding received daily under-the-skin injections that successfully controlled his condition for more than five years.
The horse did not develop any adverse effects or reoccurrence of its initial problems.
Inge Durie, from the Strömsholm Equine Referral Hospital in Sweden, and Gaby van Galen, with the Veterinary Teaching Hospital at the University of Sydney, said the horse was referred to the Swedish hospital with excessive urine production and excessive thirst.
The animal was diagnosed with central diabetes insipidus.
This form of diabetes is caused by a lack of the hormone vasopressin, which results in the production of large quantities of very dilute urine. It can have several causes.
In humans, it is normally treated with a man-made hormone called desmopressin, which can be taken as a nasal spray, as oral tablets or via injection. Companion animals have also been successfully treated with the drug, and there is a case report of a foal being treated short-term using the synthetic hormone in eye drops.
Efforts to treat the horse by giving the hormone in eye drops proved unsuccessful, but the condition was successfully controlled with daily injections under the skin.
The researchers said the horse had been imported to Sweden from Latvia eight months before it was referred to the hospital for treatment.
Immediately on arrival from Latvia, the new owner noticed the animal’s excessive water consumption. The horse was stabled on straw and the owner noticed the bedding was always excessively wet.
A month before the hospital referral, a veterinarian checked the horse and found no abnormalities on physical examination. A blood test revealed no abnormalities. A urine test was undertaken, which showed extracellular bacteria.
An antibiotic was given to treat a possible urinary tract infection, but no clinical improvement was seen.
The horse was then referred to the hospital in Strömsholm, where additional investigation led to the diagnosis of central diabetes insipidus.
Eye-drop treatment enjoyed partial success, but was limited in terms of the amount that could be given due to overflow from the eyes.
Daily injections delivered to the neck and shoulder area delivered the desired result in the horse, which was used recreationally for jumping and dressage.
One week after discharge, the owner was contacted by telephone. She reported that the horse tolerated the treatment well.
During the subsequent months and years, the owner was regularly contacted, and she continued to report that the horse was in good health, and there were no issues with treatment.
After 34 months of treatment, the owner reported that she noted more frequent urination for a couple of days. She was advised to switch to another injection site and to increase the dose because of the growth and weight gain of the horse. These measures resolved the problem.
After five years of treatment, blood and urine analyses were performed. They revealed no problems.
Discussing their findings, Durie and van Galen noted that no adverse reactions or clinical signs indicating overdose were reported during the five‐year treatment period of this horse.
“A limitation of this case report is the lack of diagnostic tests to further investigate the underlying cause of the central diabetes insipidus.”
They said the only disadvantages of the treatment were the cost (at about $US1000 a year) and the horse not being able to attend competitions because of anti-doping regulations.
“Desmopressin acetate should therefore be considered a valuable option for the long‐term treatment of horses with central diabetes insipidus.”
Long‐term hormone replacement treatment in a horse with central diabetes insipidus
Inge Durie and Gaby van Galen
Journal of Veterinary Internal Medicine, 21 January 2020 https://doi.org/10.1111/jvim.15697