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Endocrine Disease

(Adrenal Insufficiency)

General Information
Addison’s disease is a disorder of the adrenal glands in which adrenal hormone production is insufficient. The condition may result from damage to the glands by infection, cancer, or drugs, or the cause may not be known. Pituitary gland disease may also cause adrenal insufficiency.

Insufficient adrenal hormones can upset the body’s conservation of sodium (salt), reduce circulating blood volume, impair heart and kidney function, damage the heart muscle, and cause faulty sugar and fat metabolism. Decreased tolerance of stress is the primary characteristic of Addison’s disease and affected pets often present in a shock-like state of collapse called an Addisonian crisis.

Extensive blood and adrenal function tests are necessary to properly diagnose and plan treatment for Addison’s disease.

Important Points in Treatment

  1. Initial treatment of adrenal insufficiency usually is done in the hospital because of the need for intravenous fluids and medications and frequent laboratory tests. Your pet will be released as soon as the disorder can be treated effectively at home. Lifetime treatment is usually needed.


General Information
Cushing’s disease is a disorder of the adrenal glands in which excessive adrenal hormones are produced. The cause of hyperadrenalism may be abnormal pituitary gland function, tumors of the adrenal gland, “cortisone” therapy, or unexplained overactivity of the adrenal gland.

Hyperadrenalism is a slowly progressing disease, and the early signs are often not noticed. These include increased appetite, increased drinking and urination, reduced activity, and enlargement of the abdomen. As the disease progresses, these signs intensify, and the pet may become fat, pant heavily, and lose hair evenly over each side of the body. In some cases, hair loss may be the only apparent change.

Extensive laboratory tests and radiographs (x-rays) are needed to diagnose the condition, find its cause, and plan treatment. Some animals respond to medical treatment alone, while others need both surgical and medical treatment. Unfortunately, the health of some patients worsens despite treatment.

Important Points in Treatment

  1. Control, rather than cure, is the outcome of treatment in most cases of hyperadrenalism. Treatment must be carefully monitored because the drugs used in therapy may cause the underproduction of adrenal hormones known as an Addisonian crisis.

General Information
Diabetes insipidus is characterized by increased thirst and increased urination. These can result from a deficiency of antidiuretic hormone normally produced by the pituitary gland, or they may be due to the kidney’s inability to respond properly to the hormone.

Your pet may require hospitalization to confirm the diagnosis because there are several other possible causes of increased thirst and urination. With diabetes insipidus, treatment is usually necessary for the remainder of the pet’s life.

General Information
Diabetes mellitus is a disease caused by a deficiency of insulin. Insulin is a hormone produced by the pancreas and is necessary for body tissues to use blood sugar. Without insulin, sugar remains in the blood and eventually passes into the urine. This causes increased urine production and thirst. Hunger increases because the body cannot use the sugar in the blood. As the disease progresses, chemicals called ketones accumulate, resulting in vomiting and dehydration. Eventually, coma and death occur in untreated animals.

Diabetes mellitus is not a curable disease, but, with proper insulin administration, the disease can be controlled.

Important Points in Treatment

  1. Blood and urine sugar levels must be monitored very carefully until your pet’s condition is stabilized. Once your pet’s insulin requirements are determined and blood sugar levels are stabilized, only the urine sugar level needs to be monitored.

Low blood sugar reactions: Occasionally insulin treatment may result in blood sugar levels that are too low. This is most likely to happen 3 to 7 hours after insulin treatment, especially with strenuous exercise. Your pet may seem weak, tired, or uncoordinated, or may have a seizure. Always keep a sugar-containing syrup (for example, Karo) handy to treat low sugar levels. If your pet has a seizure, rub the syrup on the gums and inside the lips. Do not try to force a convulsing animal to swallow the syrup. Call the doctor if your pet does not improve within a few minutes.

Hormone reactions: Hormones present during “heat” and pregnancy antagonize the effects of insulin. Diabetic females should be spayed as soon as their insulin levels are regulated.

Re-examination: During the early weeks of treatment, several re-examinations may be necessary. Call the doctor when questions or problems arise. Make sure you fully understand all aspects of home care.

Animals Affected – Cat

General Information
Hyperthyroidism is a disease of older cats, caused by excessive production of thyroid hormones. The usual cause for increased hormone production is a tumor of the thyroid gland. These tumors may be benign (non-cancerous) or malignant (cancerous). The reason these glands develop tumors is not known.

Signs of excessive thyroid hormone production include weight loss despite a ravenous appetite, frequent bowel movements, increased thirst, and urination, restlessness, frequent crying or vocalizing, neglect of normal grooming, and rapid heartbeat. The effects on the heart may be severe and result in congestive heart failure and death.

Treatment with radioactive iodine is an excellent form of therapy. This treatment, however, requires the availability of nuclear medicine facilities and the isolation of the cat during treatment.

Drug therapy is also available. Some cats have problems with hyperthyroid medications, so monitoring with blood tests is necessary.

Surgical removal of the thyroid gland is sometimes effective for treatment. If the gland is totally removed, replacement thyroid hormone is given for life.

General Information
Hypothyroidism is a disease caused by insufficient levels or abnormal functioning of thyroid hormone. In some pets, the pituitary gland is involved, but most cases are the result of inadequate production of hormones by the thyroid.

The condition rarely appears in pets under 2 years of age; middle-aged or older pets are usually affected. Signs include some or all of the following: reduced stamina, increased sleeping, reduced tolerance to cold, dry coat and skin, premature graying of the muzzle, hair loss, slow hair growth, recurrent skin infection, and the appearance of dark pigment in the skin. The face may appear puffy, and females may have irregular cycles and/or reduced fertility. Males have a shrinkage of the testes and show less interest in females.

Important Points in Treatment

  1. Blood tests are necessary to diagnose the condition and monitor treatment.
  2. Hypothyroidism is controlled rather than cured, and lifetime therapy is necessary.

General Information
Nutritional hyperparathyroidism occurs in young animals fed diets containing improper amounts of calcium and phosphorus. It is most common in young cats. The disease develops in the following

A balanced diet for your pet contains nearly equal amounts of calcium and phosphorus. Most meats, however, contain very high levels of phosphorus in relation to calcium. Beef liver, for example, contains 52 times as much phosphorus as calcium. When such a food constitutes the main diet, more phosphorus than calcium enters the animal’s bloodstream.

The parathyroid glands (small glands in the neck) produce a hormone that restores the proper proportions of calcium and phosphorus. If little dietary calcium is available, the needed calcium must come from the only other available source: the animal’s own bones.

Removal of calcium from the bones severely weakens them, and signs begin to develop. If the condition is untreated, the bones may bend or even fracture. Eventually the animal cannot walk or support its weight, and it may die.

Important Points in Treatment

  1. Radiographs (x-rays) are necessary to evaluate damage to the bones. Blood tests are used to monitor calcium and phosphorus levels.

Animal and Bird Medical Center of Palm Harbor