Addison’s Disease (Hypoadrenocorticism)

What is Addison’s?

Hypoadrenocorticism more commonly known as Addison’s, is a deficiency in the production of corticosteroids. These are produced by the adrenal glands located just in front of the kidneys. The outer area of the gland is called the cortex and this is the area which produces the hormones called corticosteroids.

These hormones help to regulate the body’s metabolism. They are also released into the bloodstream at times of stress to adapt to a situation, preparing the body for a flight or fight response.  Without these hormones, even small stresses can lead to physical collapse.

Clinical signs

  • Listlessness
  • Occasionally vomiting and diarrhoea
  • Lack of appetite
  • Tremors and muscle weakness
  • Generally appearing unwell with symptoms that wax and wane with stress
  • In severe cases collapse due to shock- Addisonian crisis

Diagnosis

Depending on the severity of the case, diagnosis is often made while the dog is experiencing an Addisonian crisis. This is when they present to the veterinary surgeon suffering from shock like symptoms, usually with no history of suffering a trauma or toxic exposure.

Shock treatment is initiated which involves intravenous fluid therapy and blood sampling. An elevation in the dog’s kidney (renal) parameters/ an increase in their potassium levels and a decrease in their sodium levels are usually found.

An ACTH Stimulation test is then usually performed if Addison’s is suspected. ACTH is a hormone which controls the production and release of corticosteroids from the adrenal glands in times of stress.  It is produced by the pituitary gland which is a pea sized gland located at the base of the brain.

The ACTH test requires bloods to be taken before and after the administration of a synthetic version of the hormone by intravenous injection. In a healthy animal there will be an increase in the cortisol level following the administration of ACTH. An Addisonian dog does not have any corticosteroids to respond with.

Treatment

The treatment for Addison’s is to replace the missing hormones using medication containing fludrocortisone. The dog’s electrolyte levels are closely monitored along with kidney parameters and the dose of medication altered accordingly. Medication will be required for the rest of your dog’s life but most dogs return to leading a normal active life.

Useful Links:
www.myaddisonsdog.co.uk