What are the common causes of low blood sugar?

Common causes of hypoglycaemia include prolonged refusal to eat, inadequate energy intake, pancreatic or metabolic problems, and certain medicines or toxic exposures. If symptoms recur, ask your vet about further testing.

If my pet refuses food at home, what should I observe first?

First note when the refusal to eat began, how appetite has changed, whether there is vomiting or diarrhoea, and your pet's energy and activity level. Use your phone to record any seizures or unusual behaviour, and seek veterinary care promptly if needed.

What tests will the vet perform at the clinic?

Your vet will usually check an immediate blood glucose level and vital signs first, then arrange blood biochemistry, electrolytes, urinalysis, and imaging such as ultrasound or X-rays. Advanced imaging or biopsy may be recommended if further assessment is needed.

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

Low Blood Sugar and Appetite Loss in Dogs and Cats: Symptoms, Blood Glucose Tests & Care [2025]

Hypoglycaemia can be caused by insulinoma, liver disease, sepsis, or young animals going too long without food. Signs include weakness, seizures, and reduced consciousness. Emergency glucose support can help quickly, but the underlying cause still needs to be found.

Take 1 minute to check the symptoms first

Last updated: 2026/01/17

Pethealthmap Editorial Team

Sources: AAHA, ACVIM, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Repeated seizures, or cannot be awakened and breathing is weak
•Sudden collapse or brief loss of consciousness with no clear response
•Persistent extreme weakness and inability to stand without assistance

Schedule a veterinary appointment as soon as possible (within 24-72 hours)

•Appetite is clearly reduced for more than one day in a row
•Noticeable lethargy while still able to eat small amounts
•Several episodes of occasional dizziness or brief weakness

01What symptoms suggest something is wrong?

Pets with hypoglycaemia or reduced appetite often show changes in energy, activity, or behaviour. In severe cases, seizures or brief loss of consciousness may occur.

Low energy, a vacant stare, or sleepiness, with slower responses
A clear drop in appetite or complete refusal of meals and treats
Reduced activity, an unsteady gait, or trembling
Weakness, briefly being unable to stand, or slow movement
Sudden seizures, shaking, or changes in consciousness; record a video if possible
In some cases, increased appetite with abnormal weight change or weight loss

Seek emergency care immediately if you notice the following symptoms:

⚠️ Repeated seizures or cannot be woken
⚠️ Sudden collapse or brief loss of consciousness
⚠️ Persistent extreme weakness and unable to stand without help

02How can you assess abnormal signs at home? Key observations and when to seek emergency care

Before the vet visit, you can observe and record key changes at home. These details can help your vet narrow down the likely causes more quickly.

Record changes in alertness, the time each episode occurs, and how long it lasts
Track food intake over three consecutive meals, including whether treats are accepted
Note daily water intake and urination or bowel movement frequency, along with any abnormalities
Weigh your pet at the same time each week and record the trend
Use your phone to video any seizure or unusual behaviour so your vet can review it
If your pet is taking medicines or supplements, note the name and the most recent dose time

03How will the vet diagnose it? Common tests

At the clinic, your vet will prioritise blood glucose and vital signs, then arrange blood tests and imaging as needed to look for the possible cause.

Physical examination with immediate blood glucose and vital sign checks, including heart rate and breathing

Blood tests, including blood glucose, biochemistry, and electrolyte assessment

Urinalysis or urine glucose testing to help assess metabolic status

Chest and abdominal X-rays or abdominal ultrasound to assess organ structure

CT/MRI or tissue sampling (biopsy) if further assessment is needed

Follow-up may be recommended at a clinic or hospital with endocrinology or diagnostic imaging capability

04How is it treated and managed after diagnosis? Medication, diet changes, and home care

Treatment focuses on stabilising blood glucose, managing any underlying or related problems, and using diet plus follow-up monitoring to reduce the risk of recurrence.

During the acute phase, stabilising blood glucose and maintaining vital signs are the first priorities
Further medical management is planned based on the cause, such as pancreatic or endocrine disease
Diet may be adjusted, with regular measured meals to reduce large swings in blood glucose
Rechecks may include blood glucose curves and blood biochemistry, with the plan adjusted as needed
The clinic may arrange follow-up tests or specialist referral to confirm the treatment direction
Continue recording symptoms and appetite at home, and return for scheduled rechecks as advised

05What should you prepare before seeing the vet? Key details that help identify the cause

Write down when the symptoms started, how often episodes occur, and daily changes

Bring notes or a chart of food and water intake from the past three days

Prepare records of recent toileting habits and weight changes

List all current medicines, supplements, and the most recent dosing times

Save videos of seizures or unusual behaviour and bring them to the clinic

Consider booking a clinic that can measure blood glucose promptly, or an endocrinology service if advised

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.

Related Symptoms (You May Also Be Looking For)

Incoordination

Sudden weakness

Decreased activity

Reduced exercise capacity

Paresis

Partial paralysis

Polyphagia

Excessive hunger