Canis ISSN: 2398-2942

Acromegaly

Synonym(s): Excess growth hormone

Contributor(s): David Bruyette , Richard Squires

Introduction

  • Chronic overgrowth of connective tissue and bone.
  • Cause: persistent excessive growth hormone (GH).
  • Signs:
    • May be mild glucose intolerance or overt diabetes mellitus because GH diabetogenic.
    • Cardiomyopathy; systolic murmur, gallop.
    • Congestive heart failure; pleural effusion, pulmonary edema.
    • Arthritis.
  • Diagnosis: biochemistry, urinalysis, radiography.
  • Treatment: mild erythrocytosis with severe insulin resistant diabetes mellitus can be controlled with high insulin dose BID (isophane insulin injection (NPH)).
  • Prognosis: survival time 8-30 months. Most die of complications, eg CHF, CRF, neurological signs.

Pathogenesis

Etiology

  • Progesterone induced.
    Either Prolonged administration of progestagens → hypertrophy and hyperplasia of pituitary somatotrophs.
    Or Following diestrus: mammary gland → excess GH → circulation and into milk.
    Or Pituitary neoplasia (rarely).
    Some progestagens are diabetogenic independently of GH effects, possibly mediated through their glucocorticoid activity.
  • Pituitary neoplasia - large acidophil adenomas.
  • Hypothalamic neoplasia.

Pathophysiology

  • Growth hormone → insulin-like growth factors synthesized and released from liver → promotion of cartilage, bone, cardiac and skeletal muscle and connective tissue growth.
  • Growth hormone also → lipolysis and hyperglycemia.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

  • Recent references from PubMed and VetMedResource.
  • Schwedes C S (1999) Transient diabetes insipidus in a dog with acromegaly. JSAP 40 (8), 392-396 PubMed.
  • Van Herpen et al (1994) Production of antibodies to biosynthetic human growth hormone in the dog. Vet Rec 134 (7), 171 PubMed.
  • Rijnberk et al (1993) Disturbed release of growth hormone in mature dogs - a comparison with congenital growth hormone deficiency. Vet Rec 133 (22), 542-545 PubMed.
  • Selman P J et al (1991) Progestins and growth hormone excess in the dog. Acta Endocrinologica 125 Suppl 1, 42-7 PubMed.
  • Campbell K L (1988) Growth hormone-related disorders in dogs. Comp Cont Ed 10 (4), 477-482 VetMedResource.


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