Updated March 25, 2021
Insulinomas are tumours of the beta cells in the pancreas. Most cases are diagnosed due to signs resulting from an excessive production of insulin.
Which Animals get Insulinoma?
In dogs, larger breeds from middle age are at the highest risk, although the tumour is always rare in this species.
By contrast, insulinoma is one of the most common tumours of ferrets, also usually from middle age.
The Signs Of Insulinoma
Signs are intermittent, often mild, and can include:
- lethargy
- loss of fitness
- hind leg weakness or ataxia
- collapse
- mental confusion
- muscle tremors or seizures
Signs are due to low blood glucose, called hypoglycaemia. Therefore they are often more common when more glucose is needed such as after exercise or excitement.
Diagnosis of Insulinoma
Insulinoma is suspected when:
- the symptoms are associated with a low blood glucose
- the symptoms get better when glucose is given
- the blood insulin level is high
As insulin production can be irregular, not finding these does not rule it out. Confirmation can only be made by identifying tumours in the pancreas via ultrasound examination or exploratory surgery. However, in most cases, this is not necessary.
Check the other causes of leg weakness in ferrets and ataxia in dogs, muscle tremors and seizures in dogs by following the links.
Treatment of Insulinoma
Acute emergencies need to be treated with intravenous fluids containing glucose. However, most mild cases respond to cessation of activity.
Feeding very frequent small meals containing complex carbohydrates can control mild cases. It’s a good idea to avoid vigorous exercise as well.
Prednisolone is used when dietary management alone is not effective. This is a hormone that raises blood sugar levels. If there is a poor response or relapse, a second drug, diazoxide is usually added.
Surgery is a good idea to remove as much of the tumour as possible. Ahough curative surgery is rarely possible, dogs can live with good quality of life for an extended period.
Prognosis
It’s certainly not hopeless.
In dogs, one study of medical treatment alone showed a median survival time of 74 days. However, this increased to 381 days with surgery. A more recent study reported survival times of 785 days after surgery, rising to 1316 days if prednisolone was used at recurrence of hypoglycaemia. A further study in 2021 showed overall survival of 20 months after surgery, compared with 8 months for medical treatment alone.
Diabetes is a risk after surgery in up to 10% of cases.
Ferrets appear to do very well on prednisolone treatment.
Related: Diabetes in dogs & cats
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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.