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==Description==
==Description==
Insulinomas are well slow growing, encapsulated, functional tumours of the beta cells of the pancreatic islet cells, They secrete inaappropriately high amount of insulin irrespective of the serum glucose level. They are predominantly malignant (90% of canine isulinomas), with a high metastatic rate to regional lymph nodes, liver and omentum. 60% of isulinomas are carcinomas, which are more likely to be endocrinologically active, the others being adenomas.
Insulinomas are slow growing, well-encapsulated, functional tumours of the beta cells of the pancreatic islet cells. They secrete inappropriately high amount of insulin irrespective of the serum glucose level. They are predominantly malignant (90% of canine insulinomas), with a high metastatic rate to regional lymph nodes, liver and omentum. 60% of isulinomas are carcinomas, which are more likely to be endocrinologically active, the others being adenomas.
==Diagnosis==
==Diagnosis==
===Clinical Signs===
===Clinical Signs===
The following signs are attributal to hypoglycaemia:
The following signs are related to hypoglycaemia:
*collapse
*collapse
*muscle tremor
*muscle tremor
*mentally dull and disorientated
*mentally dull and disorientated
These sigs may be intermittent at the beginning of the disease, but this becomes progressively more often. In between hypoglycaemic episodes, the animals are normal. A presumptive diagnosis can be made on the demonstration of the Wipple's triad. This includes presence of clinical signs associated with hypoglycaemia, fasting hypoglycaemia and amelioration of clinical signs with the admistration of glucose. Insulinoma should be considered especially when clinical signs are associated with exercise, extended fasting or after feeding.
These signs may be intermittent at the beginning of the disease, but they become more often with time. In between hypoglycaemic episodes, the animals are generally normal. A presumptive diagnosis can be made on the demonstration of the Wipple's triad. This includes the presence of clinical signs associated with hypoglycaemia, fasting hypoglycaemia and amelioration of clinical signs with the administration of glucose. Insulinoma should always be considered when clinical signs are associated with exercise, extended fasting or after feeding.
====Other Tests====
====Other Tests====
*A tentative diagnosis can be made if inappropriately high serum insulin level in the presence of hypoglycaemia is shown.
*A tentative diagnosis can be made if an inappropriately high serum insulin level in the presence of a hypoglycaemia is shown.
===Histopathology===
===Histopathology===
This is needed to confirm the diagnosis.
This is needed for confirmation the diagnosis.
===Diagnostic Imaging===
===Diagnostic Imaging===
====Radiography====
====Radiography====
A thoracic radiograph may be used to identify any pulmonary metastases, but this is uncommon.
A thoracic radiograph may be used to identify any pulmonary metastases, but it is uncommon for insulinomas to metastasise to the lungs.
====Ultrasonography====
====Ultrasonography====
Occasionally, it may be possible to visualise the location of the tumour on the pancreas. However, this may not be possible if the tumous is too small. Metastases to lymph nodes and liver can sometimes be revealed.
Occasionally, it may be possible to visualise the location of the tumour on the pancreas. However, this may not always be possible, especially if the tumour is too small. Metastases to lymph nodes and liver can sometimes be seen.
==Treatment==
==Treatment==
===Medical===
===Medical===
This is more suitable to patients in which surgery has been declined or when surgery is inappropriate or fails due to the presence of metastasis.
This is more suitable for patients in which surgery has been declined or when surgery is inappropriate or fails due to the presence of metastasis.
*Small and frequent meals (3-6 times/day) of a simple carbohydrate content.
*Small and frequent meals (3-6 times/day) of simple carbohydrate content.
*Exercise restriction.
*Exercise restriction.
*Prednisolone to increase hepatic glucose prodection and decrease cellular glucose uptake.
*Prednisolone to increase hepatic glucose production and decrease cellular glucose uptake.
*Diazoxide, an oral hyperglycaemic drug, to inhibit pancreatic insulin secretion and tissue glucose uptake
*Diazoxide, an oral hyperglycaemic drug, to inhibit pancreatic insulin secretion and tissue glucose uptake.
===Surgery===
===Surgery===
A partial pancreatectomy is suitable for patients with a solitary tumour, provided there is no metastasis. Complications such as persistent hypoglycaemia, pancreatitis, diabetes mellitus, epilepsy and diffuse polyneuropathy can occur.
A partial pancreatectomy is suitable for patients with a solitary tumour, provided there is no metastasis. Complications such as persistent hypoglycaemia, pancreatitis, diabetes mellitus, epilepsy and diffuse polyneuropathy can occur.
==Prognosis==
==Prognosis==
This is dependent on the WHO staging of the tumour. A stage I and II can expect a median survival time of 18 months whereas it is only 6 months for a stage III. Patients suitable for surgical excision has better prognosis than those treated medically.
This is dependent on the WHO staging of the tumour. A stage I and II can expect a median survival time of 18 months whereas it is only 6 months for a stage III. Patients suitable for surgical excision has better prognosis than those treated medically.
==References==
==References==