Pituitary Insufficiency (Pituitary Dwarfism) in Dogs and Cats

1 Symptoms

Pituitary insufficiency in the young is a disease in which one, several, or all pituitary hormones are lacking, lowering target-organ hormone synthesis and secretion; these hormones include cortisol, thyroxine (T4), or growth hormone.

It is an autosomal recessive inherited disease from inbreeding, most common in German Shepherds; cats are rarely affected. Affected pups grow normally with littermates until about 2 months, then development clearly lags: incomplete coat change, lack of guard hairs, small stature but proportional body.

Symmetric alopecia, hyperpigmentation, thin inelastic skin, and scaling appear. Deciduous teeth are retained, permanent teeth delayed or absent, and bone epiphyses calcify late. Testes are small with azoospermia, the penis is small with delayed or incomplete penile-bone calcification, and the penile sheath is slack. Ovaries are dysplastic with irregular or absent estrus. Thyroid and adrenal function decrease; the pet keeps a puppy-like high-pitched voice and life span is shortened.

2 Causes and Transmission

It is an autosomal recessive inherited disease from inbreeding, most common in German Shepherds. It is not contagious.

3 Diagnosis

Diagnosis rests on recognizing the dwarfism pattern plus hormone testing that shows low pituitary and target-gland hormones. Imaging may show a small pituitary or a tumor.

Other causes of stunted growth and alopecia should be ruled out.

4 Treatment

Hormone replacement is the mainstay. Growth hormone, and when secondary thyroid or adrenal deficiency exists, thyroid hormone or corticosteroids may be given under veterinary direction.

Good nutrition supports growth, and treating skin changes while preventing secondary infection are parts of routine care.

5 Prevention

Responsible breeding and avoiding inbreeding prevent many recessive genetic diseases, including this one.

Early hormone therapy can improve quality of life and longevity.