Addison’s disease (hypoadrenocorticism) is triggered by lower-than-normal hormone development by the adrenal glands, such as Cortisol. Small glands that are situated near the kidneys are the adrenals.
To regulate salt, sugar, and water balance in the body, adrenal hormones are essential. Addison’s disease occurs less often in dogs than the other disorder, Cushing’s disease (cortisol overproduction), and is rare in cats.
In young to middle-aged female dogs, Addison’s disease occurs most frequently. The average diagnostic age is approximately four years old.
Addison’s disease’s signs may be serious and immediately apparent, or may occur intermittently and vary in severity. Weakness, exhaustion, loss of appetite, vomiting, diarrhea, and sometimes increased thirst (polydipsia) and increased urine production can be signs of (polyuria).
When a pet is stressed, they produce more Cortisol in their adrenal glands, which helps them cope with stress. Since dogs with Addison’s disease are unable to produce enough Cortisol, they are unable to cope with stress, so when stressed, the symptoms can occur or worsen. It depends on his/her temperament what a dog considers stressful.
Any shift in their daily routine, such as boarding or having house guests, is traumatic for many dogs and can precipitate or exacerbate Addison’s disease symptoms.
When a pet is stressed, they produce more Cortisol in their adrenal glands, which helps them cope with stress. Since dogs with Addison’s disease are unable to produce enough Cortisol, they are unable to cope with stress, so when stressed, the symptoms can occur or worsen.
It depends on his/her temperament what a dog considers stressful. Any shift in their daily routine, such as boarding or having house guests, is traumatic for many dogs and can precipitate or exacerbate Addison’s disease symptoms.
Sick dogs also exhibit a pattern of changes called a stress leukogram in their white blood cells (WBCs). Cortisol triggers this pattern of changes in the WBCs.
The lack of a stress leukogram in a sick dog can be a sign of Addison’s disease being taken into account. The urine is also diluted. Increased potassium in the blood can cause life-threatening heart rhythm irregularities.
Such anomalies can cause a sluggish and erratic heart rate and can be seen on an electrocardiogram (ECG). No unique anomalies are seen in X-rays of dogs with Addison’s disease. The heart can appear smaller than usual, and it is seldom possible to expand the esophagus (the tube from mouth to stomach).
The history, physical examination, and initial laboratory tests are suspicious of Addison’s disease, but in order to prove the disease, a more specific test, an ACTH challenge, should be performed.
For Addison’s disease, there are two types of care; in-hospital treatment and long-term treatment. To neutralize potassium’s effects on the heart, very sick dogs with Addison’s disease need intravenous fluids, cortisol-like medicines, and medications.
Long-term therapy requires the delivery of one of two types of hormones: either a daily pill or a shot given approximately every 25 days. Because, in response to stress, dogs with Addison’s disease can not produce more Cortisol, stress should be reduced whenever possible.
Increasing the number of hormones provided during periods of stress might be important (e.g., boarding, surgery, travel, etc.). Dogs will live a long and happy life with proper care for Addison’s disease.
Causes of Addison’s Disease in Dogs
The cause of Addison’s disease in dogs is unclear in most cases. Veterinarians believe that an autoimmune problem occurs in several of these cases.
Addison’s disease may also be caused either by a metastatic tumor, hemorrhage, infarction, granulomatous disease, adrenolytic agents such as the mitotane drug, or a drug as trilostane that activates adrenal enzymes by killing the adrenal gland.
The body is no longer able to produce glucocorticoids and mineralocorticoids, specifically aldosterone and Cortisol when anything interferes with the adrenal gland. This results in a wide variety of complications, including death in acute cases of Addison’s disease.
Scientists do not know what causes Addison’s disease precisely, but any dog, whether a purebred or mixed-breed dog, may develop Addison’s disease.
However, some breeds seem to be predisposed to the disease:
- Standard Poodles
- West Highland White Terriers
- Great Danes
- Bearded Collies
- Portuguese Water Dogs
- Nova Scotia Duck Tolling Retrievers
- Soft Coated Wheaten Terriers
Addison’s disease, irrespective of age or gender, can affect any breed of dog, as well as mixed-breed dogs, but it is most common in young, female, and middle-aged dogs.
Symptoms of Addison’s Disease in Dogs
Thanks in part to the broad array of symptoms associated with the disorder, Progressive Addison’s disease is difficult to diagnose. It is also called the great imitator.
In general, Addison’s dogs may experience recurrent gastroenteritis bouts, poor appetite, slow loss of body condition, and an inability to respond to stress properly. It’s important to note that Addison’s disease symptoms can wax and wane.
The reduction in the production of aldosterone has a pronounced effect on the body. This leads to changes in sodium, chloride, and potassium serum levels, affecting the kidneys. This, in turn, leads to heart and circulatory system issues.
In almost every important tissue in the dog’s body, Cortisol, the other significant steroid hormone affected by Addison’s, plays a role. It controls glucose production, regulates metabolism, influences fat and protein breakdown, regulates blood pressure, suppresses inflammation, stimulates red blood cell formation, and counteracts stress.
The reduction of aldosterone and cortisol production triggers the symptoms most often seen by pet owners and veterinarians with the disease.
Addison’s disease symptoms include:
- Anorexia (lack of appetite)
- Weight loss
- Bloody stools
- Alopecia (hair loss)
- Increased urination
- Increased thirst
- Weak pulse
- Irregular heart rate
- Low temperature
- Painful abdomen
- Hyperpigmentation of the skin
Diagnosing Addison’s Disease in Dogs
During an Addisonian crisis, Addison’s disease is generally diagnosed. The condition enters an acute stage during an Addisonian crisis, and dogs suffer life-threatening symptoms such as shock and collapse.
Veterinarians conduct a series of tests after the dog is recovered from the crisis to assess what caused the breakdown and to rule out other diagnoses. To get a full blood count and biochemistry, they will do blood work and most likely do a urinalysis.
Anemia and abnormally elevated blood potassium and urea levels are symptomatic of Addison’s, along with increases in blood levels of sodium, chloride, and calcium. Low urine concentrations can also be revealed by urinalysis, and your doctor may run an electrocardiogram (ECG) to check for changes in the heart of your dog.
An adrenocorticotropic hormone (ACTH) enhancement test is the definitive test for Addison’s. By adding the synthetic hormone ACTH, this test tests the activity of the adrenal glands. Before and after ACTH is given, veterinarians calculate the concentration of Cortisol. This lets us know if the adrenal glands are normally functioning.
Treating Addison’s Disease in Dogs
To treat Addison’s disease in dogs, the first thing veterinarians do is to address the issue. An adrenal crisis is described as an acute medical emergency in the Merck Veterinary Manual.
To treat the effects of the crisis, your dog will be hospitalized and undergo intensive rehabilitation. Your veterinarian will prescribe a substitute hormone drug to help your dog cope with the deficiency until your dog is out of immediate risk.
More than one drug is commonly prescribed: a monthly injectable mineralocorticoid (usually DOCP) and a daily steroid (prednisone). In order to ensure the drug is functioning properly, a veterinarian will normally prescribe annual or biannual blood work.
There is no curable Addison’s disease. For the remainder of his life, your dog may continue to take these replacement hormones, and the dose will need to be changed as time passes, particularly during periods of stress.
Without checking with their veterinarian, it is very important that owners do not attempt to modify the drug or change brands, as this may lead to another hormonal imbalance.
It takes time to find the best Addison’s disease dose for your dog. Be prepared to periodically visit the veterinarian for the first month after diagnosis, so your veterinarian can test your dog’s hormones and electrolyte levels.
This helps to find the best medication for your dog from your veterinarian. After that, expect your dog to take a shot of replacement hormones once a month and ensure that you meet any additional drug guidelines that might be recommended by your doctor.
Preventing Addison’s Disease in Dogs
Normally, Addison’s disease is not preventable. The exception to this is an Addisonian crisis caused by medication. If your dog is on mitotane or trilostane medications for Cushing’s disease, make sure you are aware of the symptoms of Addison’s disease in dogs, as an accidental overdose can lead to a crisis. Keep these drugs out of your dog’s reach at all times, and make sure you closely monitor your dog’s medications.
A rapid withdrawal of a medication such as prednisone can sometimes cause Addison’s. The only way to avoid severe problems like Addison’s disease is to follow your doctor’s advice on your dog’s medicine.
Speak to your doctor for more information about Addison’s disease in dogs. This article is not intended as a veterinary advice substitute. Call your veterinarian immediately if you believe that your dog might have Addison’s or be having an Addisonian crisis.
- Addison’s Disease: VetMed
- Addison’s Disease in Dogs: Symptoms, Diagnosis, Treatment, and Prevention: American Kennel Club