Addison’s disease, an endocrine disorder, bears the name of the doctor that first diagnosed the condition in humans, Dr Thomas Addison of Guy’s Hospital, London. He originally recorded the condition in 1855 and referred to it as a progressive destruction of the adrenal glands, the result being a deficiency in the secretion of hormones produced by the two adrenal glands. This condition is not to be confused with Cushing’s disease or hyperadrenocorticism which also affects the adrenal glands. In this situation, there is an excess secretion of the hormone cortisol rather than a lack of it, therefore Addison’s disease is the hormonal opposite of Cushing’s disease.
The disease, also called hypoadrenocorticism or adrenal insufficiency, also occurs in dogs where it affects certain breeds in particular, Standard Poodles, Great Danes, Bearded Collies, Portuguese Water Dogs and Soft Coated Wheaten Terriers. Most of the affected dogs are young to middle aged females, however, the disease can affect any dog of any age or sex. Addison’s disease is rare, although it is possibly undiagnosed in a fair number of dogs.
THE ROLE OF THE ADRENAL GLANDS
All dogs have two adrenal glands, one positioned by each of the kidneys. Each is made up of two distinct layers, the outer cortex and the inner layer called the medulla. The cortex, which is generally the part affected by Addison’s disease, secretes two important hormones, cortisol (a glucocorticoid type hormone, also called hydrocortisone) and aldosterone (a mineralocorticoid hormone). The release of these hormones is regulated by the pituitary gland through secretion of a hormone referred to as adrenocorticotropic hormone (ACTH). The medulla in contrast, is involved with the sympathetic nervous system, secretes only adrenaline which is involved in the fight and flight reaction amongst other things.
THE ROLE OF CORTISOL & ALDOSTERONE
Both of these hormones are needed for a number of vital functions in the body.
Cortisol, is involved in some important functions within the body:
- Modulating the immune system and inflammation
- Maintenance of blood pressure
- Regulating the action of insulin in controlling blood sugar levels
- The metabolism of glucose
- Regulating how the body uses protein, fats and carbohydrates
- Helping the body cope with stress
Aldosterone plays an altogether different function, acting through the kidneys to:
- Increase the reabsorption of sodium
- Increase the secretion of potassium
- Increase the reabsorption of water, helping to retain water within the body thereby increasing blood pressure
- Help regulate blood pressure in conjunction with other hormone systems which lower blood pressure
TYPES OF ADDISON’S DISEASE
There two of Addison’s disease:
- Primary or Typical
- Secondary or Atypical
In the first type, the hormone secreting cells of the cortex are damaged by an immune mediated reaction where the amimal’s own immune system attacks the cells of the adrenal cortex. This results in a failure to secrete both cortisol and aldosterone in the normal amounts needed to maintain good health so both mineralocorticoid and glucocorticoid functions are affected.
Secondary Addison’s disease in contrast, arises from a failure of the pituitary gland to stimulate the adrenal glands with ACTH, normally through lack of production of ACTH. Only glucocorticoid function is affected so there is no risk of the acute condition occurring referred to as an Addisonian crisis. However some dogs with the secondary form of the disease do progress to the primary form due to ultimate lack of aldosterone production.
Knowing which form of the disease your dog has is important as it influences the type of treatment which will be prescribed.
SIGNS & SYMPTOMS of ADDISON’S DISEASE
The symptoms of Addison’s disease are often vague or indefinite and may come and go making diagnosis difficult. The signs may also occur in a wide variety of other conditions causing additional problems with diagnosis. In Addison’s disease however, the symptoms reflect the roles which the hormones cortisol and aldosterone play in the body. When insufficient amounts of these hormones are secreted, signs which you might see include:
- Lethargy or lack of energy
- Signs of depression
- Poor or picky appetite
- Muscle weakness
- Muscle tremors
- Pain originating from around the back leg region
- Gastrointestinal upsets including vomiting or diarrhoea
Less common symptoms include:
- Inability to maintain blood sugar/glucose levels possibly leading to epileptic fits
- Interference with nerve function particularly affecting the oesophagus
If the illness continues undiagnosed and treated, then eventually the adrenal glands will not be able to produce sufficient hormones for the body to function. This leads to a set of acute symptoms known as an Addisonian crisis which occurs when the body is not able to react physiologically to stress. Signs to look out for include:
- Sudden collapse
- A fall in blood pressure
- Abnormal heart rhythm
- Evidence of dehydration
In addition blood samples may reveal:
- A fall in blood sugar levels
- A rise in the level of potassium in the blood and a fall in the level of sodium
- A rise in blood urea and creatinine levels, waste products excreted by the kidneys
DIAGNOSING ADDISON’S DISEASE
Addison’s disease can imitate so many other conditions that it is often very difficult to diagnose from both physical symptoms and from blood samples. In fact around 30% of dogs are first diagnosed at the crisis stage which shows just how difficult the disease is to pick up routinely. Routine blood screens may pick up abnormal levels of both Sodium and Potassium but are not diagnostic in their own right. The only definitive way of diagnosing the disease is to carry out a very specific tear called an ACTH stimulation test.
ACTH is normally produced by the pituitary gland and stimulates the adrenal gland to produce the hormone cortisol. To diagnose Addison’s disease, a synthetic form of ACTH, called Synacthen, is injected after having taken a blood sample to measure the normal resting level of cortisol (which is fairly easy to measure). One hour later another sample is taken to determine the response of the adrenal gland to the injection of Synacthen. In normal dogs, the level of cortisol should rise in response to the injection. In cases of Addison’s Disease, then the cortisol level will barely rise or possible show no change at all. Some drugs can affect the results of the test, especially some steroid type drugs such as prednisolone.
TREATING ADDISON’S DISEASE
Dogs in Addisonian Crisis need immediate care as the condition can be life-threatening. Prompt treatment with intravenous fluids and injections of cortisone usually provides rapid improvement reversing the signs of dehydration, normalising blood pressure and heart rhythm and stabilising the levels of both sodium and potassium.
Addison’s Disease needs long-term management as the condition is not curable. This is normally done by using synthetic steroids in the form of tablets to compensate for or replacing the natural steroids that are not being produced by the animal’s own adrenal glands. Steroid drugs commonly used for treating both primary and secondary Addison’s Disease include:
- Hydrocortisone tablets
- Prednisolone tablets
- Prednisone tablets
In cases of secondary Addison’s Disease there is an underproduction of the mineralocorticoid aldosterone as well, in which case a special steroid drug is prescribed as well:
- Fludrocortisone acetate tablets (trade name Florinef)
HOW DENES CAN HELP
Most dogs with Addison’s disease will do well with conventional medication, although there may an increase in both thirst and appetite as side effects from the drugs. Specific herbal and homeopathic support is available but would need to be under the guidance of a vet that specialises in alternative medicine.
Denes products which offer general support for Addison’s patients include:
Aloe has many benefits for the body including:
- Immune system support
Aloe optimises the immune system helping it to function more effectively and efficiently by increasing the activity of the white blood cells in fighting infection.
- Anti-inflammatory effects
One of the main benefits of aloe is its ability to reduce inflammation and the symptoms which accompany it.
Detoxification of the tissues generally provides some benefit in making both animals and people feel better and improving general health.
- Support for the digestive system
Aloe vera is particularly good for the digestive system. It is known to help with absorption of nutrients from the gut and to promote peristalsis, the natural rhythmical motion of the bowel which propels food along.
- As a source of essential nutrients
Containing a wide range of vitamins, minerals and amino acids, aloe provides good background support in conjunction with feeding good diet.
- Antioxidant actions
Aloe can protect the cells of the body against damage from free radicals, which disrupt the body’s ability to repair and detoxify itself.
All-in-One contains several plant based ingredients which can support the health of the body during times of illness:
Seaweed, or Kelp, is widely used as a herbal remedy and as a general supplement. It is particularly good for encouraging the growth of the hair and in improving the condition of the coat. Seaweed is a good source of iodine and, consequently, acts as a tonic for the thyroid gland.
Wheatgrass is derived from wheat plants, which are harvested early in growth when the green plant is only a few inches tall. The harvested plants contain a wide range of vitamins and nearly all of the minerals needed for good health as well as chlorophyll and a range of enzymes. The health benefits are varied and include cleansing the lymphatic system, acting as a blood tonic, removing toxins from cells and supporting the liver and kidneys. In particular, chlorophyll has a reputation as a healer and in supporting the immune system.
Barleygrass is a little like wheatgrass and nutritionally is very similar in composition although said to be more balanced in the range of nutrients it contains. The health benefits are broadly similar, but barleygrass can also help with cell repair, scavenge damaging free radicals from the blood, reduce inflammation, improve the condition of the coat and skin and enhance overall vitality.
Familiar to all of us, spinach is a green vegetable superfood with a multitude of health benefits. It is a rich source of minerals, vitamins and phytonutrients beneficial for a number of vital functions. It supports the health of the eyes (helping prevent cataracts), nervous system, cardiovascular system (in particular heart muscle), skin, bones and muscles.
- Alfalfa Leaf
Alfalfa is Arabic for the “father of plants”, based on its reputation in having extensive roots, which reach deep into the soil, bringing up nutrients from deep below including an extensive range of trace minerals such as calcium, potassium, iron and zinc. It also contains a wide range of vitamins. As a herbal remedy it has a reputation in helping with kidney problems, diabetes, arthritis, stroke prevention and with supporting the digestive and musculoskeletal systems.
This powdered combination of herbs soothes and protects the lining of the digestive tract and firms up the contents so it is an ideal product to help solve diarrhoea and vomiting issues with dogs with Addison’s Disease.
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