What is Cushing’s Disease?
Hyperadrenocorticism (HAC) also known as Cushing’s disease in pets is a disorder in which excessive adrenal hormones are produced. It can be caused by abnormal pituitary gland function, tumors of the adrenal gland, or by high levels of doctor-prescribed steroid use.
Pituitary-dependent HAC accounts for about 80% of all cases. It is a slowly progressive disease and the early signs are often unnoticed. These include increased appetite, increased drinking and urination, reduced activity, and a swollen abdomen.
Extensive laboratory tests, radiographs (x-rays) ultrasounds may be needed to diagnose the condition, find its cause, and plan treatment.
What Symptoms Can Present as the Disease Progresses?
- Progressive weakness of the hind limbs
- Worn nails
- Difficult rising
- Knuckling of the toes
- Scuffing hind feet
- Wearing of the inner digits of the rear paws
- Loss of muscle in the rear legs
- Tremors of the rear legs
- Persistent early stages
- Urinary and fecal incontinence
- Eventual front leg weakness from compensatory strain
- Mental stress/anxiety
- Pressure sores on bony prominences
- Inability to rise
- Muscle atrophy
- Poor hygiene-soiled appearance
- Organ failure
Crisis – Immediate veterinary assistance needed regardless of disease
- Difficulty breathing
- Prolonged seizures
- Uncontrollable vomiting/diarrhea
- Sudden collapse
- Profuse bleeding – internal or external
- Crying/whining from pain*
*It should be noted that most animals will instinctually hide their pain. Vocalization of any sort that is out of the ordinary for your pet may indicate that their pain and anxiety have become too much for them to bear. If your pet vocalizes due to pain or anxiety, please consult with your tending veterinarian immediately.
Common Signs of Pain
Panting, lameness, difficulty sleeping, pacing, abnormal posture, body tensing, poor grooming habits, tucked tail, dilated pupils, licking sore spot, muscle atrophy, decreased appetite, vocalizing/yowling, reclusive behavior, aggressive behavior, avoiding stairs/jumping, depressed, unable to stand.
How is Cushing’s Disease Treated?
Some animals respond to medical management alone while others need both surgical and medical treatment. Control, rather than cure, is the outcome of treatment in most cases of HAC. Medical treatment consists of either mitotane (Lysodren) or trilostane.
Patients on these medications must be closely monitored. Non-invasive adrenal tumors are best removed surgically. If adrenal hormones are suppressed too much, a condition called Addisons’ disease develops and can be life-threatening if untreated.
What Is the Prognosis for Cushing’s Disease?
The long-term prognosis is poor and most animals are euthanized within 6 months to 3 years of diagnosis, as the disease progresses to the point of permanent paraplegia. When the patient can no longer walk, and mobility carts are not an option, long-term hospice care or euthanasia should be considered.