PPID (aka Equine Cushings Disease)

Pituitary Pars Intermedia Dysfunction is a long name for a disease with a long list of symptoms. It is a complicated disease that has its origin at the pituitary gland which is located at the base of the brain. The pituitary gland is responsible for releasing hormones that regulate many functions in the horse's body. This gland has multiple "lobes" and with PPID, the middle lobe becomes enlarged. This enlargement results in more hormones being released but it also compresses adjacent areas of the brain and causes them to loose function.

Clinical signs associated with PPID can vary depending on the severity of the disease. Most horses with PPID are older with the average age being 20 years old (its been documented in horses ranging from 7-42 years old). It can also affect all breeds. The most common sign/symptom of PPID is failure to shed a long curly hair coat after winter. Increased water intake and increased urination can also be a common complaint. The list of symptoms also includes laminitis, repetitive foot abscesses, muscle wasting, changes in appetite, susceptibility to infections, and lethargy.

Some horses with PPID also have insulin resistance (a version of horse diabetes).

These horses often have cresty necks and abnormal fat deposition. Horses with insulin resistance are at an even higher risk of developing laminitis.

Diagnosis is made with a blood test that measures a hormone called ACTH. In horses with PPID, ACTH is elevated. The treatment of choice for PPID is a once a day tablet called pergolide. This drug slows release of hormone from the enlarged pituitary gland. After treatment is initiated, your vet may choose to re-test ACTH levels to confirm that the dosage is correct. Over time, the gland may continue to enlarge and the dose may need to be increased. Controlling the hormone release from that gland greatly improves quality of life by quieting the symptoms associated with the disease.