For several years, the backbone of treating pituitary pars intermedia dysfunction (PPID), popularly known as equine Cushing’s disease, involved administering day-to-day doses of a specific medication pergolide. However, could there be another choice ahead? Researchers from Europe recently described a novel - and still experimental - surgical process designed for treating PPID that is seeing inspiring results.
Equine Cushing’s disease refers to a disorder of the pituitary glands pars intermedia triggered by an adenoma, a form of tumor. Classic signs, mostly seen in older horses, include loss of muscle tone, an abnormal hair coat, chronic laminitis, and altered fat deposition.
In humans with the Cushing’s disease - a related but different condition - removal of surgical pituitary growth is the treatment of choice. However, none of the presently employed surgical methods used in humans would be possible in the horse. Particularly, the human-based surgery would mean drilling through many centimeters of the bone in a horse and using long, narrow equipment to reach the tumor; the tools do not presently exist.
Signs and Symptoms
The symptoms of the Cushing's disease are same to those observed in any other causes of Cushing's syndrome. Patients with the Cushing's disease often show one or more signs and symptoms secondary to the existence of excess ACTH, or cortisol. Even though unusual, some patients with the Cushing's disease have huge pituitary tumors, or macroadenomas.
In addition to the adverse hormonal effects associated with increased levels of blood cortisol, a huge tumor can compress nearby structures. These tumors can also compress the nerves which carry essential information from the eyes, resulting in a decrease in peripheral vision. Cataracts and glaucoma also may take place in the Cushing's syndrome.
In children, the two major symptoms are reduced linear growth and obesity. The most common symptoms observed in male patients are muscle atrophy, purple striae, kidney stones, and osteoporosis.
The clinical diagnosis must be developed based the presence of one or more common symptoms, since the syndrome itself has no obvious pathognomonic signs or symptoms
Common signs and symptoms of the Cushing's disease include:
- Poor short-term memory
- High blood pressure
- Weight gain
- Impaired immunological function
- Excess hair growth (women)
- Red, ruddy face
- Extra fat around neck
- Moon's face
- Irregular menstruation
- Poor concentration
- Red stretch marks
Aimee Sakes, MSc, from the Bio-Mechanical Engineering Department of the Delft University of Technology in the Netherlands, explained that no surgical procedures in human medicine allow sufficient access to the pituitary gland in a horse body. As such, Sakes and her colleagues thought creatively to create a new method for performing surgery in the horses with the equine Cushing’s. What they developed was an endovascular, or an intravenous, surgical technique.
As it manifests, horses are very lucky to have a distinct connection between the pituitary gland and the superficial facial vein. Additionally, Sakes added that the superficial vein can be used to guide a flexible tool toward the pituitary gland. This is possible since a flexible prototype device having a distal cutting edge is inserted into the superficial facial vein.
The device is guided toward the pituitary gland and can successfully remove the intended tissue from the pituitary gland in the cadaver of the horse. This simulates the possibility of pituitary tumor removal in the live horses.
Various study authors are still developing their prototype procedure and instrument, anticipating the technique will be able to boost the result and the quality of life in horses suffering from the Cushing’s disease in future.
Image credit: en.wikipedia.org
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