Mary Allen
Is your otherwise energetic furry friend suddenly tired all the time? When you walk, does it just trott behind you slowly instead of pacing up and down like she usually does? These could be signs of the rare disease Addison’s disease. In this case, it is advisable to consult a veterinarian. Because Addison’s disease has life-threatening effects!
What is Addison’s Disease?
Hypoadrenocorticism, also known as Addison’s disease, is a relatively rare disease of the adrenal glands and often goes unnoticed. Underactive adrenal glands result in a deficiency of the stress hormone cortisol and the hormone aldosterone, which is important for mineral metabolism. Dogs of all ages are affected, but younger bitches are more likely to be affected.
Addison’s disease is also referred to as the “great deceiver” because the symptoms cannot be assigned given the similarity to other diseases. With the help of professional long-term treatment in which cortisol and aldosterone are administered, it is still possible for the sick dog to lead a normal life.
How Does the Disease Come About?
The causes of Addison’s disease are diverse, but not fully understood. For the sake of simplicity, the triggers are therefore divided into primary and secondary Addison’s disease.
Primary Addison’s disease
Most four-legged friends suffer from primary Addison’s disease. The main cause of this “type” is the destruction of the adrenal tissue and thus the adrenal cortex area that produces the hormones aldosterone and cortisol. These two hormones are essential to life as they maintain normal cell function. However, due to the damage in the adrenal cortex area, these hormones can no longer be produced sufficiently, causing the cortisol and aldosterone levels in the blood to drop.
A lack of cortisol results in gastrointestinal problems, problems regulating the immune system or energy metabolism, and a lack of a suitable stress response. Impaired potassium excretion (triggered by aldosterone deficiency) can result in severe cardiac arrhythmia and a slow heart rate. Because the kidneys do not adequately control the sodium balance, dangerously low blood pressure and reduced blood flow to important organs result.
There are several possible causes of damage to the adrenal cortex. Certain large dog breeds, such as the Great Dane or the Leonberger, are particularly prone to Addison’s disease. Autoimmune diseases, infections, or tumors are also possible triggers. Furthermore, an overactive adrenal gland, which in the worst case leads to multiple organ failures, is given as a reason for the destruction of the adrenal cortex area.
Secondary Addison’s disease
This “type” of Addison’s disease is less common and is caused by a disorder of the pituitary gland (pituitary gland) or hypothalamus. These two areas of the brain are the superordinate control centers of the adrenal glands and thus of hormone regulation. If no more adrenocorticotropic hormone (ACTH) is formed or if too much corticotropic releasing hormone (CRH) is produced, cortisol production stops.
What are the Symptoms?
The symptoms vary depending on whether the disease occurs due to a cortisol or aldosterone deficiency. Dogs that are deficient in both hormones are usually the most severely ill. General symptoms include weakness, general malaise, and depressive behavior. Other signs include vomiting, loss of appetite, drinking more, weight loss, (bloody) diarrhea, severe tiredness, tremors, and a slow heartbeat.
These already serious symptoms can be followed by a “total failure” (Addison crisis), sudden collapse, shock symptoms, or gastrointestinal bleeding. These conditions are life-threatening and require urgent veterinary attention!
How is Addison’s Disease Diagnosed?
Due to the rarity and the non-specific symptoms, the diagnosis is extremely difficult. To be able to conclude with certainty about Addison’s disease, several (blood) tests are usually necessary. If there is a suspicion, a routine blood test is carried out first.
The vet pays particular attention to changes in the two electrolytes sodium and potassium. A low urine density, narrow vessels, or a reduction in the size of the adrenal glands also confirm the suspicion.
For the diagnosis, the veterinarian carries out a so-called ACTH stimulation test. First of all, he measures the current cortisol level. He then injects ACTH into the dog and takes another blood sample about an hour later. If an increase in the cortisol level can be detected, Addison’s disease is not present. However, if the value remains unchanged, Addison’s disease is extremely likely.
However, since the cortisol level fluctuates considerably over the day, even in healthy dogs, this test is unfortunately only suitable for ruling out Addison’s disease and not for a 100% diagnosis.
What Does the Treatment Look Like?
Addison’s disease is incurable but treatable. There is long-term therapy or the treatment of an Addisonian crisis – the therapeutic approach differs depending on the condition of the four-legged friend concerned.
In long-term therapy, depending on which hormone is missing, glucocorticoids or mineralocorticoids are administered. Dog patients usually have to take these medications for life. Regular check-ups with the vet are necessary until the blood levels have normalized and the right dose of medication has been found. After that, checks every four to six months are sufficient.
In the case of an Addisonian crisis, extensive treatments must be used, for which the fur nose is hospitalized in most cases. To stabilize the circulation, liquid therapy is carried out via infusions. Furthermore, the four-legged patient gets a supply of crystalloids (e.g. sodium) and glucocorticoids to normalize the hormone balance. In addition, the veterinarian treats the excess potassium by administering calcium gluconate. During these treatment steps, an ACTH test is carried out again and again.