Acromegaly in the dog

Area of Science:

• Veterinary Medicine
• Endocrinology
• Canine Health

Background:

• Canine acromegaly is characterized by excessive growth hormone (GH) production, often linked to progestagen administration or natural progesterone influence.
• Clinical signs include soft tissue proliferation, leading to facial changes, abdominal enlargement, and respiratory stridor.

Purpose of the Study:

• To outline the characteristic clinical, radiographic, and biochemical findings in canine acromegaly.
• To establish diagnostic criteria for acromegaly in dogs.
• To investigate the role of progestagens and the effect of their withdrawal on GH levels and clinical signs.

Main Methods:

• Clinical examination and radiographic assessment for soft tissue changes.
• Measurement of basal and potentially non-suppressible plasma growth hormone (GH) levels.
• Assay of GH-dependent insulin-like growth factor I (IGF-I) concentrations.
• Evaluation of clinical response following progestagen withdrawal or ovariohysterectomy.

Main Results:

• Characteristic findings include soft tissue mass increase (orolingual, oropharyngeal, orolaryngeal), skin folds, abdominal enlargement, and respiratory stridor.
• Hyperglycemia, PU/PD, elevated serum alkaline phosphatase (SAP), and lowered packed cell volume (PCV) may be present.
• Elevated basal plasma GH and drastically elevated GH-dependent insulin-like growth factor I are diagnostic hallmarks.
• Progestagen withdrawal or ovariohysterectomy led to reduced GH and IGF-I levels and clinical improvement.

Conclusions:

• Canine acromegaly diagnosis relies on identifying characteristic physical changes and confirming elevated GH and IGF-I levels.
• Progestagen influence is a key factor in the development of acromegaly in susceptible female dogs.
• Therapeutic interventions targeting progestagen withdrawal can effectively manage canine acromegaly.