犬のアジソン病：副腎が機能しなくなったとき
アジソン病は副腎が十分なホルモンを産生しないときに起こります。この病気の症状、診断、治療について学びましょう。
Addison's disease, or hypoadrenocorticism, is a condition where the adrenal glands fail to produce enough cortisol and aldosterone. These hormones are essential for regulating stress response, fluid balance, and electrolyte levels. While less common than Cushing's disease, Addison's is a serious condition that can be life-threatening if untreated. The good news is that most dogs respond well to lifelong hormone replacement therapy. (Source: VCA Hospitals)
- Caused by insufficient cortisol and aldosterone production from the adrenal glands
- Signs are often vague and wax and wane, making diagnosis challenging
- Certain breeds are at higher risk, including Portuguese Water Dogs and Standard Poodles
- An Addisonian crisis (sudden collapse) is a medical emergency requiring immediate treatment
- Diagnosis uses the ACTH stimulation test to measure cortisol response
- Most dogs live normal, happy lives with daily medication
What Is Addison's Disease?
The adrenal glands are small, paired glands located near the kidneys. Each has an outer cortex and inner medulla. The cortex produces two critical hormones: cortisol (a stress hormone) and aldosterone (which regulates sodium and potassium levels for fluid balance). In Addison's disease, the adrenal cortex is damaged, most commonly by the dog's own immune system attacking the gland. Without enough cortisol and aldosterone, the body cannot maintain normal fluid and electrolyte balance, leading to a cascade of symptoms.
Recognizing the Signs
Addison's disease is often called 'the great imitator' because its signs are vague and non-specific. Common signs include: lethargy, decreased appetite, vomiting, diarrhea, increased thirst and urination, weight loss, and intermittent shaking. Signs often come and go, temporarily improving with non-specific treatment but then returning. This wax-and-wane pattern is a classic clue. Breeds at higher risk include Portuguese Water Dogs, Bearded Collies, Standard Poodles, Nova Scotia Duck Tolling Retrievers, Leonbergers, Great Danes, and Labrador Retrievers.
Addisonian Crisis
An Addisonian crisis is a life-threatening emergency that occurs when cortisol levels drop critically low. Signs include sudden severe weakness, profuse vomiting and diarrhea, dehydration, abdominal pain, and sometimes collapse. This requires immediate hospitalization with aggressive IV fluid therapy and emergency corticosteroid administration. If you notice sudden collapse or severe lethargy with vomiting in your dog, seek emergency veterinary care immediately.
Diagnosis and Treatment
Diagnosis starts with blood work showing low sodium and high potassium (electrolyte imbalances), along with clinical signs. The definitive test is the ACTH stimulation test, which measures cortisol levels before and after injection of synthetic ACTH. Treatment involves lifelong hormone replacement: desoxycorticosterone pivalate (DOCP, sold as Percorten-V or Zycortal) injected every 3 to 4 weeks to replace aldosterone, often supplemented with a low daily dose of oral prednisolone. Alternative oral medication fludrocortisone (Florinef) can replace both hormones. Once stabilized, most dogs require minimal monitoring and live completely normal lives.
- Vague, recurring episodes of lethargy and vomiting
- Increased thirst and urination without obvious cause
- Sudden weakness or collapse
- Unexplained weight loss
- Vomiting and diarrhea that comes and goes
- Any sudden collapse with severe weakness (emergency)
RVC
RVC's experienced veterinarians can diagnose Addison's disease using the ACTH stimulation test and other blood work. Our team manages long-term hormone replacement therapy with regular monitoring to keep your dog healthy. If your dog shows signs of Addison's disease or experiences a collapse, call +853 6677 6611 immediately.
+853 6677 6611