Difference between revisions of "Insulinoma"
| Line 18: | Line 18: | ||
==Description== | ==Description== | ||
| − | Insulinomas are | + | 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 | + | The following signs are related to hypoglycaemia: |
*collapse | *collapse | ||
*muscle tremor | *muscle tremor | ||
| Line 30: | Line 30: | ||
*mentally dull and disorientated | *mentally dull and disorientated | ||
| − | These | + | 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. |
| Line 38: | Line 38: | ||
====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 | + | 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 | + | 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 | + | 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 | + | 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 | + | *Small and frequent meals (3-6 times/day) of simple carbohydrate content. |
*Exercise restriction. | *Exercise restriction. | ||
| − | *Prednisolone to increase hepatic glucose | + | *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== | ||
Revision as of 10:53, 23 August 2009
 |
This article is still under construction. |
Signalment
- More common in dogs than cats
- Middle-aged to older dogs
- No sex predilection
- Breed predisposition, more common in medium to large-breed dogs:
- Irish Setter
- German Shepherd
- Labrador Retriever
- Standard Poodle
- Boxer
Description
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
Clinical Signs
The following signs are related to hypoglycaemia:
- collapse
- muscle tremor
- muscle weakness
- ataxia
- mentally dull and disorientated
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.
Laboratory Tests
Biochemistry
- Hypoglycemia
Other Tests
- A tentative diagnosis can be made if an inappropriately high serum insulin level in the presence of a hypoglycaemia is shown.
Histopathology
This is needed for confirmation the diagnosis.
Diagnostic Imaging
Radiography
A thoracic radiograph may be used to identify any pulmonary metastases, but it is uncommon for insulinomas to metastasise to the lungs.
Ultrasonography
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
Medical
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 simple carbohydrate content.
- Exercise restriction.
- 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.
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.
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.
References
- Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company.
- Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier
- Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.
- Polton, G. A., White, R. N., Brearley, M. J. and Eastwood, J. M. (2007) Improved survival in a retrospective cohort of 28 dogs with insulinoma Journal of Small Animal Practice 48:151-156 [1]