Susie, Diabetic Cat
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Susie, Diabetic Cat.  Click here for main index page

Introduction | Hypoglycaemia | Ketoacidosis | Emergencies | Other


When managing a condition like diabetes in a cat, things can sometimes go wrong and complications can develop.  Some of these can be medical emergencies, whilst others are less critical.

Two of the more serious complications are mentioned below, hypoglycaemia and ketoacidosis.  They have different causes, but both are serious and can be fatal if ignored.  Other less critical or less common complications are covered at the end of this page.



This is a serious condition in which the level of sugar (glucose) in the blood has dropped to dangerously low levels.  With a well regulated diabetic cat, this is probably the most likely complication to arise.

It is normally caused by too much insulin, and it is sometimes known as "insulin shock" or simply as a "hypo".  Urgent treatment is always required, although if the symptoms are mild, treatment at home in the form of feeding a source of sugar can reduce the risk of the condition worsening.  If more severe, the situation may become critical and emergency veterinary help may be needed.  It can be fatal if not treated promptly.

One of the factors that can lead to a hypo is if a cat is injected with its normal dose of insulin then either doesn't eat or is ill after eating.  At time of writing, Susie has had 3 hypos since becoming diabetic, all relatively mild, and all were caused by her being ill and not eating.

In a hypo, the blood glucose level becomes too low, and the essential organs including the brain are not able to function properly.  At this stage there may be a variety of symptoms depending on how severely the cat is affected.  If the hypo is mild, the cat might become lethargic and unresponsive, or appear drunk.  More serious signs are indicated in the table below.

Sugar has to be provided urgently.    If the cat is conscious, the easiest way is to give syrup.  Any syrup will do - maple syrup, corn syrup, karo syrup, it doesn't matter, they are all sources of sugar in a liquid form.  How to administer the syrup depends on the condition of the cat.  With Susie, she has lapped it up from a saucer and I have fed her directly from my finger.  In severe cases, perhaps if the cat is semi-conscious, I have read that it might be necessary to smear some syrup onto the gums.

Keep some Syrup Handy
Not long after Susie first became diabetic, I read some advice on another website.  It recommended keeping a bottle of syrup in a handy place, because when faced with your first hypo, it's likely to be very stressful and frantic!  They were right.  When you need the syrup in an emergency, the last thing you'll want is to have to empty a kitchen cupboard in a panic!  I was very glad that I had followed that advice.  Ever since, I kept a small bottle of syrup next to Susie's insulin syringes, so that I always know exactly where to find it.

Somogyi Effect
This is a natural defence of the body against rapid onset of hypoglycaemia.  If the body can detect that the blood sugar levels are falling too quickly, it can sometimes produce a rapid release of sugars into the bloodstream.  Some key points about the Somogyi effect:

  • it is also known as "rebound hyperglycaemia".
  • it is thought to be triggered by the speed of blood sugar levels falling, and might therefore occur even before a hypo develops.
  • if a hypo develops more slowly, the Somogyi rebound might not occur at all.
  • if a Somogyi rebound is triggered, the blood glucose will be high, but it is crucial to interpret this correctly.  It is caused by a defence against a rapidly developing hypo.
  • The presence of a Somogyi response therefore requires a reduction in insulin, despite the high blood sugar.



This is a complication caused by diabetes which has not been stabilised adequately, or perhaps not identified and treated at all.  Ketoacidosis can be mild or severe, and in its most severe form, it is a medical emergency and can be fatal.

It is basically caused from toxic waste products that are produced when the body has to keep itself going by using fats instead of sugars.  The sugars (glucose) can't get from the blood into the cells because of the lack of insulin, so the body has to find something else to keep itself going.  If too much fats are used at once, the quantity of waste is too high for the body to dispose of, so it starts to build up in the blood.  The waste products (ketones) are normally taken out of the blood by the kidneys and passed out of the body in urine.

Early signs can be identified by using test sticks, dipping them into a urine sample.  The sticks that I use for Susie are Keto-Diastix (manufactured by Bayer).  They have 2 coloured strips, one for glucose the other for ketones.  Positive results for ketones are indicated on a 5 point scale according to the extent of colour change.  Any positive ketone reading should be discussed with your vet, but repeated positive readings or single moderate to large results are more urgent.  A typical scale is shown in the photograph below.  Units might vary in packs sold in different countries, but the colour change will be the same.

Keto-Diastix colour chart - click for larger image - opens in new browser window/tab

Treatment for severe ketoacidosis is normally regarded as a medical emergency and may require a saline drip for rehydration as well as a faster acting insulin and close medical supervision.  For this reason, it is always recommended that treatment be carried out by a veterinary professional, whether at the surgery or at a veterinary hospital.  I have never seen any exceptions to this mentioned elsewhere, but in December 2000, I received an e-mail from somebody whose cat had been hospitalised for mild ketoacidosis 3 times in 6 months, developed further complications and the vet had given up hope.  The owner gathered supplies to treat him at home and was able to do so successfully when the need arose.  This is of great credit to her dedication and tenacity, but is very much an exception.  The only recommendation that I have seen elsewhere is to discuss with the vet if ketones are present in the cat's urine.


Table - Emergency Actions

Below, I have reproduced a table that I keep handy for easy reference in case of emergencies.  I compiled the information from a variety of sources, including websites and various vets.

Hypoglycaemia Ketoacidosis
  • Acute low blood sugar leading to inadequate functioning of key organs including the brain
  • Usually due to excess of insulin (poor timing, reduction in diabetic condition, inadequate reading of warning signs)
  • Most likely to occur when well regulated, wrongly timed, or start of "honeymoon period" (remission)
  • Unrest
  • Trembling or shivering
  • Strange movements
  • Drunken appearance – wobbling, unbalanced, stupor
  • Head tilting
  • Muscle twitching
  • Lack of muscular co-ordination
  • Disorientation
  • Convulsions
  • Unconsciousness (coma)
  • Mild
    • Give food immediately (any food)
    • Keep a close eye for several hours
  • Moderate
    • Syrup (4-5ml) or any liquid sugar source immediately, alone or with food
    • If unable to swallow, rub on to gums, especially under tongue
    • Avoid excess liquid in mouth
    • Seek veterinary advice
  • Severe (seizures, coma)
    • Syrup immediately (gums/cheek pouch)
    • On recovery, give food
    • Watch out for symptoms returning
    • If condition worsens, call vets immediately, and in any case seek urgent veterinary advice
    • Should see a response within a few minutes. If not, call vets (emergency intravenous dextrose)
Other Points
  • Syrup is rapid, but short acting – follow up with food or more syrup
  • In general, give 1g or 1ml syrup per kg body weight
  • Always keep a check for symptoms returning
  • It is usually progressive
  • Can occasionally be symptomless, particularly if progressive warning signs have been masked by Somogyi response (the body's natural defence to rapid reductions in blood sugar)
  • If not sure, treat as hypo
    • If wrong, high blood glucose for a few hours won't cause any long term harm
    • If right, you might have just saved your cat's life!


  • Build up of ketones in the blood, as a result of excessive metabolising of fat
  • When starved of glucose, the body’s cells will start to use fat as a substitute
  • Most likely to occur when diabetes is poorly regulated
  • Increased drinking
  • Increased urinating
  • Decreased appetite
  • Sickness
  • Diarrhoea
  • Dehydration
  • Sometimes a ketone (acetone) smell on the cat's breath
  • Ketones in urine (Keto-Diastix)


  • Take into vets
  • If severe, might need urgent re-hydration (saline drip) and very fast acting insulin
  • Increase insulin dosage, with advice from vet, in order to reduce the risks of a repeat
Other Points
  • Can be fatal if not treated



Other Complications


This is another critical complication of uncontrolled diabetes that I only became aware of after receiving an e-mail in 2001.   Like the other two complications above, it is serious and can lead to coma and even death if not treated urgently.  It therefore requires urgent or emergency veterinary treatment.  I've not included it with the 2 complications above, because hyperosmolarity is extremely rare.

It can occur when too much water has been lost from the blood through the urine and it is effectively an extreme form of dehydration.  This causes the concentrations of salts in the blood to increase to dangerously high levels.  Treatment is based on urgent rehydration, intravenous drip in the most severe cases.  Once the acute short term problems are under control, the underlying cause should be addressed so that the diabetes can be brought back under control.

Hyperosmolarity can occur with or without ketoacidosis, so it is possible that some ketones may be present in the urine. In ketoacidosis, it is the ketones that cause the problem. In hyperosmolarity it is the high concentrations of salts.


Long Term Effects

As well as the acute complications caused by things going out of control and causing immediate problems, there can also be longer term effects from diabetes in cats, just as there can be in diabetic people.  Some of the long term effects in cats include:

  • Hind leg weakness - this seems to be specific to cats, but is still very rare.  Also known as diabetic neuropathy.
  • Strain on essential organs - especially the kidneys (with all the extra work removing sugars) and also the heart.
  • Cataracts - a less common complication in diabetic cats, more common in diabetic dogs.


Important note:  All information and opinion in the Susie, Diabetic Cat pages is from personal experience.  Nothing in these pages is intended to be a substitute for proper professional advice, which should always be sought from a qualified veterinary surgeon.

This page was last updated
May 2006