L30: Feline Diabetes Mellitus (Brooks) Flashcards
Short-acting insulins
- Only have 2-6 hours of effect
- not suitable for long-term management!
- best for cats with DKA that aren’t eating
- Ex: humulin R, Novalin R
- given with U-100 syringes
Intermediate-acting insulins
NPH, Lente, PZI
-max effect 2-14 hrs in cats
Long-acting insulins
Glargine (Lantus)
Detemir
Max effect 8-16 hours
See white board chart :)
:)
Dosing and frequency of insulin
-starting dose and freq. same no matter which insulin you pick:
-BID dosing
4 kg: 1.5-2 U/cat
-if BG at dx is
Dietary management
- consistent diet, portions, treats, schedule
- low carb, high protein food best to minimize postprandial hyperglycemia
- weight loss management important as obesity decreases insulin sensitivity
Weight loss guidelines
- should lose 1-2% of BW per week
- calculate requirements based on ideal weight
- reduce kcals by 10-20% every 2-4 wks
- establish diabetic management before tackling weight loss
Stomatitis, UTI, and oral glucocorticoids can –> insulin resistance
:)
-glucocorticoids should be stopped or switched to inhaled/topical form
How can diabetes promote UTI formation?
glucose in urine, and diluted urine promotes bacterial growth
Signs of hypoglycemia
Weakness
Collapse
Tremors
Seizures
When to perform reevaluations in diabetic cat
1 week, then q2-3 wks PRN until glycemic control
*often takes 1-3 months to achieve adequate glycemic control
-q4-6 mos. once control is established
What to do at 1 week recheck
- Hx, PE, BW
- blood glucose curve
- fructosamine (shouldn’t be used as only monitor)
- adjust dose as needed
If remission occurs, when does it normally occur?
In the first 3 months (relapses common)
Advantages and disadvantages of blood glucose curves
(Measure glucose q2hrs)
Adv:
-gives info on nadir, peak time and duration of effect
-can evaluate for Somogyi effect (rebound hyperglycemia)
Disadv:
- stress hyperglycemia
- laborious
- costly
- can miss Somogyi effect!
Ideal nadir
80-140 mg/dL
Ideal glucose range
80-270 mg/dL
Somogyi Effect**
- rebound hyperglycemia that can last 24-72 hours despite subsequent insulin injections
- triggered by hypoglycemia OR rapid BG decrease
- caused by counter-regulatory hormones (ie. Epi and glucagon)
- causes good glycemic control followed by poor control
- should always be considered if BGC shows persistent hyperglycemia
- can easily miss if only perform spot BGs on animal** (causes cycle of incorrectly raising insulin dose because spot BG is high, but it might actually be high because you are overdosing on insulin and they are having rebound hyperglycemia)
Fructosamine
- a glycosylated serum protein
- an indicator of BG of preceding 1-2 weeks
- higher in hyperglycemic animals
- gives good general idea of how patient was maintained in first couple weeks of tx
- can be low due to hypoproteinemia, hyperthyroid, lean cats, newly diagnosed or mild diabetes
Insulin adjustments
- made based on CS and BG results
- make gradual changes of 0.5 U/injection (or more gradual if suspect Somogyi effect)
- reduce by 25-50% if evidence of hypoglycemia
What to do at recheck 2-3 weeks after diagnosis
- repeat Hx, PE, BW, blood glucose curve, fructosamine
- discuss home monitoring or BGC and urine glucose weekly until insulin stable, then q3-4 weeks
Urine glucose renal threshold
300 mg/dL
Persistent negative glucose indicates:
Insulin overdose, or cat in remission
Persistent urine glucose indicates:
Somogyi effect or need more insulin
6-8 week recheck: what should you do if glycemic control still inadequate at this time and dose is at least 1 U/kg BID?
Look for evidence of insulin resistance:
- routine bloodwork
- oral exam
- urine culture
- hyperadrenocorticism
- acromegaly
Goals of therapy
Control of CS* Prevent complications Blood glucose: -nadir 80-140 mg/dL -range 80-270 mg/dL -fructosamine 350-450
Diabetic remission?
Causes of hypoglycemia in diabetic patient
Diabetic remission
Increased insulin sensitivity
Insulin overdose
CRF (kidneys help clear insulin normally; CRF –> decreased clearance)
Complications of diabetes
Diabetic cataracts
Diabetic neuropathy
Diabetic ketoacidosis
Which commonly used insulin often has a duration that is too short?
NPH (may need to switch to PZI or glargine)
Consequence of prolonged duration of insulin (>12 hours)
Overlap insulin action can lead to Somogyi effect or to an overt hypoglycemia
-if nadir occurs at 10+ hours, suggests duration is too long and need to switch to shorter acting insulin or once a day dosing
Diabetic cataracts
- more severe in dogs than cats
- generally doesn’t cause blindness in cats
- caused by decreased aldose reductase activity with age
- cats have less sorbitol in the lens as they get older and are less likely to get severe cataracts, but may be severe in diabetic kittens
Diabetic Neuropathy
- one of most common chronic complications in diabetic cats, but only 10% develop CS
- pathophys not fully understood (combo of obesity, hyperlipidemia, hypertension)
- causes hindlimb weakness, ataxia, m. Atrophy, plantigrade posture, etc. usually in hindlimbs
- may improve with glycemic control but is rarely reversible**
- no effective tx
Diabetic ketoacidosis
- caused by lack of insulin or insulin resistance
- if cat not eating, owners should give half dose
Goals of therapy
Eliminate CS** (PU/PD, polyphagia, wt. loss, hypoglycemia, DKA, neuropathies)
Prevent complications
Quality of life
Remission (achieved in 25-50%)
