COM - The adrenal glands of the dog
The adrenal glands of the dog are small organs located behind the kidneys. The function of the adrenal glands is to produce various types of hormones. Both an excess and a deficiency of these hormones can lead to two very different diseases. Both Addison's disease (a deficiency of adrenal cortex hormones) and Cushing's disease (an excess of hormones) have a significant impact on the life of your dog. Fortunately, both diseases can often be successfully treated. Pharmacy4pets explains how to recognize these adrenal conditions and supports your dog with adrenal problems.
The structure and function of the adrenal glands
Although the name suggests otherwise, apart from their location in the body, the adrenal glands have nothing to do with the kidneys. They are two small bean-shaped organs located just within the ribcage, against the back of your dog. The adrenal glands can be divided into the adrenal medulla and the adrenal cortex. The adrenal cortex consists of three layers, each producing a different hormone:
- Cortisol (glucocorticoid): important for regulating blood sugar levels, influences sleep patterns, and plays a role in immunity.
- Aldosterone (mineralocorticoid): important for mineral (salt) balance and thus for blood pressure.
- Androgens and estrogens: sex hormones.
Adrenal gland disorders in dogs
The two main adrenal disorders are Addison's disease, in which the adrenal cortex produces insufficient or no hormones, and Cushing's disease (or syndrome), in which problems are caused by an excess of glucocorticoids.
Addison's disease in dogs
Due to the shrinkage of the adrenal cortex, it cannot perform its hormone-producing function anymore. The shrinking of the adrenal cortex is usually due to an inflammation of the adrenal cortex.
Symptoms of Addison's disease in dogs
The symptoms of Addison's disease often become visible only in a late stage of the inflammation. The symptoms can be quite vague (but life-threatening!), which means the diagnosis is not always immediately made. The following symptoms may be observed:
- Lethargy.
- Decreased appetite.
- Muscle weakness.
- Diarrhea: often recurring periods with varying stool.
- Vomiting.
- Shock: sudden collapse, pale mucous membranes.
Diagnosis and treatment of Addison's disease in dogs
With a suspicion of Addison's disease in dogs, thorough physical examination and blood tests are very important. General blood tests often show shifts in salts (sodium and potassium), but the diagnosis must be confirmed with a specific blood test, the ACTH stimulation test.
A dog with Addison's disease can go into shock. The primary treatment for a dog in shock with a suspicion of Addison's disease is intravenous fluids combined with a glucocorticoid. Once the shock is resolved and the diagnosis of Addison's disease is confirmed, the dog should receive lifelong medication to compensate for the deficiency of adrenal cortex hormones (a glucocorticoid, mineralocorticoid, and salt).
Cushing's disease in dogs
In Cushing's syndrome, the adrenal cortex produces too many glucocorticoids. This is caused in 85% of cases by a benign tumor in the head (the pituitary gland, which controls the adrenal glands) and in 15% by a malignant tumor of the adrenal gland.
Symptoms of Cushing's disease in dogs
Dogs with Cushing's syndrome drink and urinate a lot and have a ravenous appetite. They often have poor coats, thin skin, and a distended abdomen. There are also changes in their behavior: they often pant a lot and have little energy. Female dogs stop estrus. Dogs with Cushing's disease can also develop diabetes. Because their immunity decreases (glucocorticoids have anti-inflammatory and immunosuppressive effects), they are more prone to bladder infections and skin inflammations. A pituitary tumor can cause headaches, and an adrenal tumor can cause abdominal pain. Cushing's disease mainly occurs in older dogs. Dogs of all breeds can get Cushing's, although it seems to be more common in smaller dogs.
Diagnosis of Cushing's disease in dogs
The quite typical symptoms of Cushing's disease plus the findings on physical examination often already point towards Cushing's. General blood tests mainly exclude other causes for drinking and urinating a lot (such as chronic kidney disease and diabetes). The diagnosis is made with a three-day urine test. Based on the result, a distinction can often, but not always, be made between a pituitary or adrenal tumor. This can be confirmed by abdominal ultrasound. If only one adrenal gland is enlarged, it indicates an adrenal tumor; if both adrenal glands are enlarged, it indicates that a pituitary tumor excessively stimulates the adrenals to produce hormones, causing them to enlarge.
Treatment of Cushing's disease in dogs
In the majority of dogs, Cushing's disease is caused by a benign pituitary tumor. If this tumor is small, treatment with medication is possible. This medication suppresses the production of glucocorticoids by the adrenal glands, reducing the symptoms. If the tumor is large, surgical removal may sometimes be recommended, as its size can cause severe headaches among other issues. The size of the tumor must be determined with a CT scan.
If Cushing's disease is caused by a malignant adrenal tumor, the use of the aforementioned medication is not recommended. The tumor will continue to grow and may spread. An adrenal tumor is often best treated with surgery. If the tumor has metastasized (this can be seen on a chest X-ray), treatment with a special medication that destroys the adrenal cortex and metastases of an adrenal cortex tumor is possible. The prognosis of Cushing's disease is quite good if the correct treatment is administered. However, the dog will need regular check-ups, and medication may need to be adjusted if necessary.
Although adrenal gland disorders in dogs are quite serious, they can often be successfully treated, and your dog can live well with them, albeit with lifelong medication.
Pharmacy4pets supports your dog with adrenal issues. If you have any questions about our products or about adrenal disorders in dogs, please contact us.
