Felis ISSN 2398-2950

Primary hyperaldosteronism

Synonym(s): Conn's disease

Contributor(s): David Bruyette, Andrea Harvey, Ellie Mardell

Introduction

  • Hyperaldosteronism is defined by an elevated plasma aldosterone concentration, exceeding the upper limit of the reference range, or in the case of primary hyperaldosteronism an increased ratio of plasma aldosterone to  plasma renin activity.
  • Aldosterone is normally secreted by the zona glomerulosa of the adrenal gland in response to stimulation of the renin-angiotensin-aldosterone system.
  • Aldosterone has effects on mineralocorticoid receptors in the distal renal tubules, colon and salivary glands to stimulate sodium re-absorption, and potassium and hydrogen excretion.
  • Hyperaldosteronism can be primary or secondary.
  • Primary hyperaldosteronism is characterized by elevated plasma aldosterone in the face of suppressed plasma renin activity, and occurs as the result of an aldosterone secreting adrenal tumor or adrenal hyperplasia.
  • Secondary hyperaldosteronism describes an increase in aldosterone production, occurring as a normal response to activation of the renin-angiotensin-aldosterone system, such as occurs with congestive heart failure Heart: congestive heart failure , severe hepatic dysfunction and renal failure Kidney: acute renal failure.

Pathogenesis

Etiology

  • Aldosterone secreting adrenal adenoma.
  • Aldosterone secreting adrenal carcinoma.
  • Bilateral adrenal hyperplasia.

Pathophysiology

  • In primary hyperaldosteronism there is dissociation of the renin-angiotensin-aldosterone system. Increased, autonomous aldosterone secretion occurs  →  independently from renin secretion, with loss of negative feedback.
  • Increased aldosterone causes retention of sodium, and excretion of potassium.
  • Retention of sodium results in expansion of extracellular fluid volume, leading to hypertension.
  • Excretion of potassium results in hypokalemic polymyopathy.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Rose S A, Kyles A E, Labelle P et al (2007) Adrenalectomy and caval thrombectomy in a cat with primary hyperaldosteronism. JAAHA 43 (4), 209-14 PubMed.
  • Ash R A, Harvey A M, Tasker S (2005) Primary hyperaldosteronism in the cat: a series of 13 cases. J Feline Med Surg (3), 173-182 PubMed.
  • Javadi S, Djajadiningrat-Laanen S C, Kooistra H S et al (2005) Primary hyperaldosteronism, a mediator of progressive renal disease in cats. Domest Anim Endocrinol 28 (1), 85-104 PubMed.

Other sources of information

  • Refsal K R & Harvey A M (2009) Primary hyperaldosteronism. In: August's Consultations in Feline Internal Medicine. August J R (ed). 6th edn. Chapter 24, pp 254-267.


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