Explanation of Cushings Disease

Although cushings disease occurs in different animals (horses, dogs, even people), the symptoms for each species are different. For example, in horses it causes the coat to grow longer and thicker, often becoming curly, whereas in dogs it has the opposite effect of causing hair to fall out and produce bald spots. The equine (horses, ponies, etc.) version of this illness is known as ECD (Equine Cushings Disease).

ECD is an illness caused by excessive hormone production. The pituitary gland produces too much hormone, which over-stimulates the adrenal glands, which in turn produce too much steroids. It is the excessive quantity of steroids which causes the symptoms associated with ECD. The over-production of the pituitary can be caused various changes, such as the growth of benign tumors, enlargement of the pituitary due to age-related changes, or a decline in the regulatory chemical dopamine due to age-related changes in the brain. All of these factors tend to be age related, so the disease is much more common in older horses (over 15 years) although it has been found in horses as young as seven years.

Cushings was first identified in explained in’21, by Dr. Cushing, after whom the disease is name. ECD is the equine variation of the disease first identified in humans by Dr. Cushing.

Different horses show different symptoms of Equine Cushings Disease. The most common symptom is coat changes (longer, thicker, curly, failure to shed in Spring, becoming lighter in color). The heavier coat results in increased sweating as a secondary symptom, due to over-heating, especially in summer. The horse tends to lose muscle in its neck and back, despite increased appetite and eating more, while developing a pendulous abdomen. Diabetes often develops, with an associated increase in water consumption and urination. Laminitis always develops eventually. The horse becomes more prone to infections and slower to heal from external injuries due to a depressed immune system. The natural depressions above the eyes tend to fill in with fat.

Each of these symptoms could be caused by other illnesses, so it is often a combination of them which results in ECD being diagnosed. Urine and blood tests can be used to rule out other possible causes and to confirm the presence of ECD. Studies have found that many older horses (especially ponies) have ECD than are diagnosed. Consequently, greater care is required to identify ECD in the early stages, when controlling treatment is effective.

Although ECD is not curable, it can be treated. The most common treatment is the use of medication to reduce hormone production to near normal levels, thereby slowing down the development of secondary problems.

As cushings disease can result in the development of secondary diseases (e.g. laminitis, diabetes), the horse needs to be closely monitored for any symptoms of these, with appropriate and prompt treatment.

Finally, one should make the horse more comfortable by treating the individual symptoms. If the horse is over-heating due to a heavier coat, one should clip the coat to make the horse more comfortable.

Tagged with: animals • cushing • cushings • disease • equine • horse • horses • pets

Filed under: horse health

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