Why test for ketones when cutting insulin dose?

[heatherh]

From the FMDB FAQ:

Q4.4. My cat's pre-shot level was way below the usual value. Should I give the injection?

A4.4. There's no hard and fast rule, but if you don't have data on how your cat responds to insulin, here are some general guidelines. Below 150 mg/dl (8.3 mmol/L), don't give insulin. Between 150 and 200 (8.3-11.1 mmol/L), you have three options: a.) give nothing; b.) give a token dose (10-25% of the usual dose); c.) feed as usual, test in a couple of hours, and make a decision based on that value. Above 200 (11.1 mmol/L) but below the cat's normal pre-shot value, a reduced dose might be wise. In all cases, if you are reducing or eliminating insulin, it's wise to check for ketones in the urine. Above the normal pre-shot value, give the usual dose, but if the pre-shot value is consistently elevated, it's a good idea to schedule a full glucose curve to see whether a change in dose or insulin is appropriate. In most cases, the target "peak" value should not be below 100 mg/dl (5.6 mmol/L), and for some cats it might be higher.

"In all cases, if you are reducing or eliminating insulin, it's wise to check for ketones in the urine." Why is this?

 

[Vicky & Gandalf (GA) & Murrlin]

One of the causes for development of ketones is lack of insulin. While it usually takes a cocktail of problems, such as inappetence, dehydration or infection in addition to lack of insulin for ketones to develop, blood glucose values do not have to be sky high. High BGs by themselves don't cause ketones and ketones can develop even with lower BGs, because those other factors are involved.

Here's a good explanation: http://petdiabetes.wikia.com/wiki/Ketones

 

[heatherh]

Thank you. That was informative and had some other useful links, too.