Page 246 - Problem-Based Feline Medicine

238 PART 4 CAT WITH URINARY TRACT SIGNS

Approximately 5–30% of cats have good glycemic betic cats, because it lowers blood glucose and insulin
control using oral hypoglycemic drugs which stimu- requirement, and may increase the diabetic remission
late insulin secretion. The sulfonylurea, glipizide, is the rate.
most widely used oral hypoglycemic drug for cats.
Underweight and normal bodyweight cats need a
Oral hypoglycaemic drugs are most useful as sole treat- high-quality, calorie-dense feline diet that is palatable.
ment when:
Obese cats should have their weight reduced by
● Beta cells are not markedly suppressed by glucose
1–2%/week (see page 454 The Cat With Abdominal
toxicity (e.g. blood glucose is < 16 mmol/L (< 290
Distention or Abdominal Fluid for treatment details).
mg/dl)) or
Use a high-protein, low-carbohydrate diet.
● The owner refuses to give insulin injections.
Transient diabetes.
Lente and NPH (Isophane) insulin must be given
● Approximately 20–90% of diabetic cats will
twice daily in all cats; most cats (up to 90%) require
undergo remission of their diabetes in 1–4 months,
ultralente twice daily.
if good glycemic control is achieved.
● In general, lente and NPH insulin have too short
● Remission is more common in diabetic cats
a duration of action to achieve excellent glycemic
recently treated with insulin-antagonistic drugs,
control in cats, although clinical control is often
such as megestrol acetate or long-acting steriods.
good, and signs of diabetes resolve in the majority
● Excellent glycemic control facilitates diabetic remis-
of cats.
sion, by enabling beta cells to recover from glucose
● For approximately 4 hours twice a day there is min-
toxicity. Excellent glycemic control is aided by use
imal exogenous insulin action when using these
of long-acting insulin, especially glargine adminis-
insulins. This means that most diabetic cats have
tered twice daily, and a low-carbohydrate diet.
episodes of hyperglycemia > 16 mmol/L (> 288
● Remission rates increase with increasing dura-
mg/dl) twice daily, which exacerbates glucose toxi-
tion of action of insulin, and highest rates are
city, and makes diabetic remission less likely than
obtained using glargine. PZI produces higher
when using longer-acting insulins.
remission rates than lente insulin, when both are
Long-acting insulins such as glargine, detemir and administered twice daily.
PZI in most cats provide better glycemic control and
Hypoglycemia kills cats.
higher remission rates than lente, NPH and ultralente,
● Teach owners to recognize signs (dazed drunken
and best results are obtained when they are adminis-
look, dilated pupils, wobbliness, weakness, head
tered twice daily.
or body tremors, twitching, seizures or coma).
Because of the small doses used in cats, 40 U/ml Signs may occur with little warning in cats that
insulin is preferable to 100 U/ml insulin. However, have apparently excellent clinical control of their
expected duration of action is more important than con- diabetes.
centration. Using 0.3 ml insulin syringes is advanta- ● The owner should immediately start treatment with
1
geous when using 100 U/ml insulin. Syringes with ⁄ 4 u honey, or a glucose syrup designed for human dia-
gradations are available. betic patients, given per os. If the cat is seizuring,
rub honey or syrup into the gums, or give per rec-
Beef or pork insulins have a longer duration of
tum using the lubricated insulin syringe, if the nee-
action than human insulin. Most insulins for veterinary
dle can be removed.
use are pork or beef/pork mixes. Human-use insulin is
– Cats with severe signs require intravenous glu-
either identical to amino acid sequence in human
cose or glucagon.
insulin, or has substitutions to alter duration of action.
– Give 50% dextrose at 0.5–1.0 ml/kg IV.
Eating does not need to be coordinated with insulin – If intravenous access is not possible, 50% dex-
administration, because the postprandial increase in trose (0.5–1.0 ml/kg) or corn syrup (0.25–0.5
blood glucose is very prolonged (18+ h) in cats. Evidence ml/kg) administered per os, or rubbed on the
suggests that a high-protein, low-carbohydrate diet gums may be effective, but glucagon 0.25–1.0
(6–12% of calories from carbohydrate) is best for dia- mg IM is superior. Glucagon must be followed