Cat Addison’s Disease (Feline Hypoadrenocorticism)

Addison’s disease or hypoadrenocorticism is a disorder of the endocrine system due to insufficient production of the adrenal gland hormones. Addison’s disease affects young cats, although it is a relevantly rare disease. The condition is very treatable but can be fatal without proper veterinary care.

Causes

The most common cause of Addison’s disease in cats is the destruction of the adrenal tissue, mainly due to the over active response of the cat’s immune system, causing it to attack and destroy its own tissues. Other causes that can also cause the condition are diseases of the pituitary gland, adrenal gland infiltration due to lymphosarcoma, and certain infections. In rare cases, the cause can be due to an abrupt discontinuation of a steroid medication.

Therefore, cats that have been on steroids for any condition over a long period of time should always be weaned off of them slowly so as to avoid Addison’s disease.

Signs and Symptoms

The signs and symptoms of Addison’s disease in cats are often very vague and usually mimic other diseases. The clinical signs to watch out for may include vomiting, weight loss, dehydration, excessive thirst (polydipsia), lethargy, poor appetite, weakness, excessive urination (polyuria), low heart rate, shaking, and low body temperature.

The signs and symptoms of the disease are most commonly misinterpreted as an infection of the gastrointestinal tract (bacterial, viral, or fungal), cat Kidney Disease (pyelonephritis or acute kidney failure), inflammatory bowel disease (IBD), neoplasia or cancer of the gastrointestinal tract (adenocarcinoma or hymphosarcoma), hypercalcemia-causing diseases (parathyroid gland disease and cancer), urinary blockage, and pancreatitis.

Diagnosis

Because the disease can mimic other diseases, it is necessary to confirm the diagnosis. This can be done by undergoing clinical tests such as a complete blood count (CBC), physical examination, complete medical history, urinalysis, and a blood biochemistry profile.

One of the best methods of diagnosing Addison’s disease is through an ACTH stimulation test. This is a timed blood test administered by a veterinarian, which measures the functionality of the adrenal glands.

Depending on the clinical symptoms, some veterinarians may require a possible abdominal ultrasound and radiographs (x-rays) of the chest and abdominal areas in order to rule kidney disease and other urinary tract issues, as well as to determine the size of the adrenal glands.

Treatment

The treatment for Addison’s disease in cats usually depends on the severity of the symptoms and conditions.
For the acute phase, also known as the Addisonian crisis, usual treatments include the administration of intravenous fluids in an attempt to raise a cat’s sodium levels and lower it’s potassium levels; mineralocorticoid and corticosteroid replacement therapy, and monitoring of electrolyte and acid-base balance. Treatments for the chronic stage include daily salt supplement and mineralocorticoid and corticosteroid replacement therapy.

Glucocorticoids such as methylprednisolone acetate, prednisone and dexamethasone are indicated during the acute state and can be used as a long term therapy, depending on the case. Mineralocorticoids, on the other hand, are available in oral form (Florinef) and in an injectable form (desoxycorticosterone pivalate or DOCP). This treatment is usually given for the entire lifespan of the cat.

Prevention

If your cat is receiving steroid medication, it is never recommended to stop the medication abruptly as it can cause Addison’s disease. Other than that, there are no measures that can prevent the disease.

Home Care

At home, it is necessary to continue any medications that are prescribed by your veterinarian and remember to closely observe your cat’s appetite, water intake, and activity levels. Signs that need to be immediately reported to your veterinarian include weakness, vomiting, change in appetite and diarrhea.

To monitor your cat’s response to treatment and improvement of the condition, it is necessary to have regularly scheduled visits to your veterinarian.

It is also a good idea to either avoid or prepare for any circumstances that may cause your cat any undue physical or emotional harm or stress, such as strenuous exercise, surgeries, or a sudden change in your cat’s normal daily routine or their environment. It you do foresee any stress in your cat’s immediate future, you should consult with your veterinarian so that they may adjust your cat’s treatment accordingly.