Changes

==Description==

==Description==

[[Image:Islet cell tumour.jpg|right|thumb|100px|<small><center>Islet cell tumour (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

[[Image:Islet cell tumour.jpg|right|thumb|100px|<small><center>Islet cell tumour (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

'''Insulinomas''' are slow growing, well-encapsulated, functional tumours of the [[Pancreas - Anatomy & Physiology#Endocrine|beta cells]] of the pancreatic islet cells.  They secrete inappropriately high amount of [[Pancreas - Anatomy & Physiology#Insulin|insulin]], irrespective of the serum glucose level.  They are predominantly [[Neoplasia - Pathology#Classification|malignant]] (90% of canine insulinomas), with a high metastatic rate to regional [[Lymph Nodes - Pathology|lymph nodes]], [[Liver - Anatomy & Physiology|liver]] and omentum.  60% of isulinomas are [[Neoplasia - Pathology#Nomenclature|carcinomas]], which are more likely to be endocrinologically active whereas the others are [[Neoplasia - Pathology#Nomenclature|adenomas]].

'''Insulinomas''' are slow growing, well-encapsulated, functional tumours of the [[Pancreas - Anatomy & Physiology#Endocrine|beta cells]] of the pancreatic islets.  They secrete inappropriately high amounts of [[Pancreas - Anatomy & Physiology#Insulin|insulin]], irrespective of the serum glucose concentration.  They are often [[Neoplasia - Pathology#Classification|malignant]], with a high metastatic rate to regional [[Lymph Nodes - Pathology|lymph nodes]], [[Liver - Anatomy & Physiology|liver]] and omentum.  60% of insulinomas are [[Neoplasia - Pathology#Nomenclature|carcinomas]], which are more likely to be endocrinologically active whereas the others are [[Neoplasia - Pathology#Nomenclature|adenomas]].

Blood glucose concentration is maintained within a narrow homeostatic range because several tissues are able to use only glucose as an energetic substrate.  These tissues are particularly affected by the hypoglycaemia which occurs with hyperinsulinaemia and they include neurones, blood cells, renal medullary cells and fibroblasts in healing wounds.  The release of hormones antagonistic hormones (such as glucagon, growth hormone, glucocorticoids and catecholamines) also contributes to the pathogenesis and clinical signs observed in animals with insulinoma.   

Blood glucose concentration is maintained within a narrow homeostatic range because several tissues are able to use only glucose as an energetic substrate.  These tissues are particularly affected by the hypoglycaemia which occurs with hyperinsulinaemia and they include neurones, blood cells, renal medullary cells and fibroblasts in healing wounds.  The release of hormones antagonistic to insulin (such as glucagon, growth hormone, glucocorticoids and catecholamines) also contributes to the pathogenesis and clinical signs observed in animals with insulinoma.   

==Signalment==

==Signalment==

===Pathology===

===Pathology===

This is needed for definitive confirmation of the diagnosis.  The following features may be identified:

Collection and examination of a biopsy is needed for definitive confirmation of the diagnosis.  The following features may be identified:

*Usually single, or less often multiple, small (1-3cm) spherical nodules, yellow to dark red,  in one or more lobes

*Usually single, or less often multiple, small (1-3cm) spherical nodules, yellow to dark red,  in one or more lobes

*Small islets of acinar tissue are sometimes present within the neoplasm

*Histologically, small islets of acinar tissue are sometimes present within the neoplasm

*Pancreatic beta cells can readily be identified using immunocytochemistry

*Pancreatic beta cells can readily be identified using immunocytochemistry

==Treatment==

==Treatment==

===Emergency Stabilisation===

===Emergency Stabilisation===

In the event of a hypoglycaemic episode, a bolus of 50% dextrose solution should be given immediately.  Glucose syrup can also be rubbed onto the gums of an affected animal or a meal could be provided and this approach may reduce the risk of rebound hypoglycaemia encountered with administration of 50% dextrose solution.  Intra-venous fluid therapy can then be maintained using 2.5% dextrose solution.

In the event of a hypoglycaemic episode, a bolus of 50% dextrose solution should be given immediately by the intra-venous route.  Glucose syrup can also be rubbed onto the gums of an affected animal or a meal could be provided and this approach may reduce the risk of rebound hypoglycaemia encountered with administration of 50% dextrose solution.  Intra-venous fluid therapy can then be maintained using 2.5% dextrose solution.

===Medical Management===

===Medical Management===

*[[Steroids|'''Glucocorticoids''']] such as prednisolone prescribed to increase hepatic gluconeogenesis and to decrease cellular glucose uptake.

*[[Steroids|'''Glucocorticoids''']] such as prednisolone prescribed to increase hepatic gluconeogenesis and to decrease cellular glucose uptake.

*'''Diazoxide''', an oral hyperglycaemic drug, used to inhibit pancreatic insulin secretion and tissue glucose uptake.

*'''Diazoxide''', an oral hyperglycaemic drug, used to inhibit pancreatic insulin secretion and tissue glucose uptake.

*'''Octreotide''', a somatostatin analogue which reduces the synthesis of insulin, is rarely used for management of insulinomas.

*'''Octreotide''', a somatostatin analogue which reduces the synthesis of insulin but which is rarely used for management of insulinomas.

===Surgical Management===

===Surgical Management===

*[[Pancreatitis - Dog and Cat|'''Pancreatitis]]''' or '''Diabetes mellitus''' due to disruption to the pancreatic parenchyma during the procedure.

*[[Pancreatitis - Dog and Cat|'''Pancreatitis]]''' or '''Diabetes mellitus''' due to disruption to the pancreatic parenchyma during the procedure.

*'''Epilepsy''' and '''diffuse polyneuropathy''' due to chronic hypoglycaemia.

*'''Epilepsy''' and '''diffuse polyneuropathy''' due to chronic hypoglycaemia.

*'''Duodenal necrosis and perforation''' as the cranial pancreatico-duodenal artery may be disrupted when the right limb of the pancreas is dissected away the duodenum.

*'''Duodenal necrosis and perforation''' as the cranial pancreatico-duodenal artery may be disrupted when the right limb of the pancreas is dissected away from the duodenum.

==Prognosis==

==Prognosis==

[[Category:To_Do_-_James]]

[[Category:To_Do_-_James]]

[[Category:Cat]][[Category:Dog]]

[[Category:Cat]][[Category:Dog]]