Felis ISSN 2398-2950

Insulinoma

Synonym(s): Hyperinsulinism, insulin-secreting tumor, islet cell tumor

Introduction

  • Very rare neoplasm of pancreatic islets beta cells (only handful of cases reported).
  • Cause: functional insulin secreting neoplasm of pancreatic islet cells.
  • Signs: (hypoglycemia) episodic seizures, weakness, collapse.
  • Diagnosis: glucose and insulin levels.
  • Treatment: dietary control, prednisolone, and surgery.
  • Prognosis: guarded as tumors often malignant.

Pathogenesis

Etiology

  • Insulinoma - functional tumor of pancreatic beta cells.

Pathophysiology

  • Hyperinsulinemia   →   decreased rate of glucose release from the liver plus increased uptake of glucose by insulin-sensitive tissues   →   hypoglycemia.
  • Hypoglycemia   →   reduced glucose available to the central nervous system (CNS) and later to peripheral nervous system and organs   →   seizures, lethargy, weakness, ataxia, bizarre behavior, coma.
  • Prolonged, severe hypoglycemia may   →   irreversible brain damage   →   rarely death due to secretion of diabetogenic hormones (most notably glucagon and adrenaline) which antagonize the effects of insulin and stimulate an increase in blood glucose concentrations.

Timecourse

  • May be chronic over weeks to months or acute onset.
  • Low blood glucose tolerated for prolonged periods without symptoms, so small changes in blood glucose produce symptomatic episodes.

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.
  • O'Brien T D, Norton F, Turner T M et al (1990) Pancreatic endocrine tumour in a cat:clinical, pathological and immunohistochemical evaluation. JAAHA 26 (5), 453-457 VetMedResource.
  • McMillan F D, Barr B, Feldman E C (1985) Functional islet cell tumour in a cat. JAAHA 21 (6), 741-746 VetMedResource.

Other sources of information

  • Canine and Feline Endocrinology and Reproduction, EC Feldman and RW Nelson (1996). WB Saunders, Philadelphia pp 422.


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