CAUSES AND DEVELOPMENT

Chronic excessive production and secretion of GH by a pituitary gland tumor results in acromegaly, also called hypersomatotropism. These are usually slow growing tumors and may be present long before the first clinical signs appear.

It is a disease seen mostly in older cats (> 10 years old). Males are predisposed.

CLINICAL SYMPTOMS

Acromegaly is one of the diseases sought for in difficult-to-control diabetes mellitus. Symptoms of diabetes mellitus are the first signs of acromegaly: increased appetite, animal urinates more and drinks more.

Physical changes can also be observed: increased space between the teeth, enlargement of the skull, legs and tongue. In some cases, cardiac and/or neurological abnormalities are also present.

DIAGNOSIS

The diagnosis of acromegaly is made by a blood test: a test of the hormone called IGF-1 which increases with the increase of GH.

A CT scan or MRI confirms the presence of a pituitary gland tumor.

If cardiac abnormalities are present, an ultrasound test of the heart is indicated.

TREATMENTS AND PROGNOSIS

Several treatment options are being considered. Each case must be studied individually in order to identify the most suitable option:

• Drug treatment with molecules that block GH but whose effectiveness is variable ;
• Radiation therapy, which reduces the size of the pituitary gland tumor with the help of radiation and thus allows for better control of clinical signs ;
• Surgery to remove the pituitary gland tumor. However, there are only a few institutions that practice this procedure because of its complexity ;
• If none of the above treatments can be considered, one can try to better manage diabetes with high doses of insulin (a treatment that lowers blood sugar levels). This is only just a supportive treatment.

In general, the prognosis is good in the short term but reserved/poor in the long term.

Dr Emilie Vangrinsven
Diplomate from European college of veterinary internal medicine | PhD U-Liège