Insulinoma is a tumour of the pancreas that commonly causes unstable blood sugar, resulting in symptoms such as lethargy, trembling, or collapse. If you suspect insulinoma, seek early veterinary evaluation and arrange blood glucose and imaging tests.

How do vets diagnose insulinoma in dogs and cats?

Vets begin with a blood glucose measurement as an initial screen, combined with haematology, biochemistry, imaging (ultrasound or CT), and specialist investigations as needed to confirm the diagnosis and locate the tumour.

Does insulinoma require surgery?

Whether surgery is needed depends on the size and location of the tumour and the animal's overall condition. Surgical resection is possible in some cases — discuss the risks and expected outcomes with your vet.

What follow-up is needed after surgery or during conservative treatment?

Regular blood glucose monitoring, biochemistry panels, and imaging are required after surgery or during conservative treatment. Dietary and management plans should be adjusted as needed — follow your vet's guidance for recheck scheduling.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Insulinoma in Dogs & Cats: Hypoglycemia Symptoms, Blood Glucose Tests & Treatment [2025]

Insulinoma is a pancreatic tumour that secretes excess insulin, causing recurrent hypoglycaemic episodes. Surgical resection is the preferred treatment; when surgery is not possible, medication and frequent small meals are used to manage blood sugar.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap editorial team

Sources: ACVIM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Repeated seizures or persistent generalized rigidity
•Sudden collapse or brief loss of consciousness
•Gums become pale or lips turn blue or purple

Schedule a clinic visit as soon as possible (within 24-72 hours)

•Frequent lethargy, slowed responses, and lack of energy
•Noticeable trembling or persistent weakness when moving
•Sudden decrease in appetite or ongoing weight loss

01What symptoms indicate something is wrong?

Insulinoma often causes low blood sugar, presenting mainly as neurological or behavioural changes. Symptoms tend to recur and vary widely, so close monitoring is essential.

Changes in mental status, or appearing lethargic and unresponsive
Looking weak, moving with difficulty, or trembling
Changes in eating habits or sudden loss of appetite
Gradual weight loss or noticeable muscle wasting
Noticeably abnormal changes in water intake or urination
Seek veterinary care promptly if symptoms recur or worsen

Seek emergency care immediately if you notice the following symptoms:

⚠️ Repeated seizures or sustained generalised tonic activity
⚠️ Sudden collapse or brief loss of consciousness
⚠️ Pale gums or bluish discolouration of the lips

02How to assess the situation at home? Key observations and when to visit the emergency clinic

Consistent observation and record-keeping at home helps your vet quickly understand the pattern and progression of episodes, aiding diagnosis and the planning of investigations.

Note the time symptoms first appeared and how often episodes occur
Weigh your pet at the same time each day and record changes
Measure and record daily water intake and frequency of urination
Film episodes or normal behaviour to show your vet
Note whether your pet ate or took any substances before an episode
If symptoms recur, arrange a specialist evaluation as soon as possible

03How will the vet make a diagnosis? Common diagnostic tests

On arrival, a blood glucose measurement is the first-line screen, followed by haematology, biochemistry, and imaging to identify the cause and locate the lesion.

Full physical examination

assessing neurological responses and hydration status

Blood glucose measurement

immediate testing for hypoglycaemia

Haematology and electrolyte panel

evaluating overall stability

Biochemistry panel

assessing liver, kidney, and other organ function

Abdominal ultrasound or CT scan

examining the pancreas and abdominal lesions

Referral to a specialist hospital with advanced imaging when necessary

04How is it treated and managed after diagnosis? Medications, dietary adjustments, and care guidance

Treatment includes acute stabilisation, surgical or medical management, and post-operative or long-term blood glucose monitoring and lifestyle management.

Acute hypoglycaemia is managed in hospital with blood glucose stabilisation and fluid therapy
Surgical resection may be a curative option in selected cases
Ongoing blood glucose monitoring is required after surgery or during conservative treatment
The effectiveness of dietary adjustments and medications should be reviewed regularly
Regular recheck appointments with blood work and imaging to monitor disease progression
A specialist referral is recommended if surgery or advanced assessment is needed

05What to prepare before seeing the vet? Key information to help your vet identify the cause quickly

Write down when symptoms first appeared and detailed notes on each episode

Record every occurrence of eating, vomiting, or seizures

List the names of all current medications and supplements

Bring recent weight records and episode videos for your vet

Bring any previous test reports or imaging studies (if available)

It is advisable to book an appointment at a clinic equipped for blood glucose testing and imaging in advance

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.