Hyperadrenocorticism

What is it?

Hyperadrenocorticism (HAC), also known as Cushing’s disease, 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), or ultrasound may be needed to diagnose the condition, find its cause, and plan treatment.

How is it 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 (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 Addison’s disease develops and can be life threatening if untreated.

What is the prognosis for Hyperadrenocorticism (HAC)?

The average life expectancy with HAC ranges from 36 months to longer with good regulation. However, clinical signs and the development of concurrent disease like diabetes may reduce this time. If HAC is caused by a pituitary tumor, the tumor may expand and put pressure on other parts of the brain causing neurologic signs and ultimately death. Infections of the skin, urinary tract, and liver are common due to the high levels of circulating steroids that suppress the immune system. Many dogs ultimately die or are euthanized due to these complications. A personalized treatment plan is important to slow the progression of HAC. Talk to your veterinarian regarding the best treatment protocol for your pet.

What symptoms can present as the disease progresses?

Early Stages

  • increased drinking and urination
  • increased appetite
  • panting
  • lethargy
  • abdominal distention
  • muscle weakness
  • mild hair loss
  • hair the won’t grow back
  • mild to moderate skin infections

Late Stages

  • persistent early stages
  • weight loss
  • muscle wasting
  • moderate to severe hair loss
  • severe skin infections
  • thin skin
  • chronic eye infections
  • worsening dental disease
  • high blood pressure
  • chronic urinary tract infections
  • incontinence
  • bladder stones
  • +/- diabetes
  • calcium deposits in the skin
  • blood clots in the lungs
  • Addisonian Crisis – weakness, vomiting/diarrhea, heart arrhythmias, seizures

Crisis – Immediate veterinary assistance needed regardless of the 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 has 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

 Download Hyperadrenocorticism brochure

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