Troubleshooting

Treating diabetic cats is not always straightforward and can be affected by a variety of factors.

Uncontrolled Blood Sugar

• Review home care, administration, and daily treatment logs
• Review insulin handling: storage; gentle handling of large, fragile protein structure; and drawing up product correctly (i.e., inversion of vial, ensure not drawing up air)
• Ensure correct measurement of required dosage: review technique, observe client drawing up insulin
• Ensure correct syringes being used: U-40 for 40 U/ml and U-100 for 100 U/ml insulins
• Ensure correct technique for subcutaneous administration: review with client, observe client administering insulin
• Ensure diet recommendations are being followed

Infection

• Appropriate diagnostic testing for infections should be pursued:
  • Urinalysis
  • Urine culture/sensitivity
  • Note: inactive sediment in urinalysis with dilute urine does not rule out a UTI
• Appropriate treatment of concurrent infections:
  • Treatment of urinary tract infection based on urine culture and sensitivity testing
  • Treatment of skin infection
  • Treatment of parasites

Dental Disease

• It may not be possible to achieve diabetic regulation until concurrent dental disease is treated.
• Management of concurrent dental disease should not be delayed as this may impact insulin responsiveness.
• Appropriate care for dental disease should be pursued:
  • General anesthesia
  • Dental radiographs
  • Surgical extraction of diseased teeth
  • Scaling and polishing of healthy teeth

Acromegaly/Hypersomatotropism

Pituitary tumor with excessive production and secretion of growth hormone

• Effects: Insulin resistant DM secondary to excess growth hormone, anabolic effects of excessive IGF-1, space occupying effect of pituitary macroadenoma
• Physical changes: weight gain, a broadened face, enlarged feet, protrusion of mandible, increased interdental spacing, organomegaly, poor coat
• Test: Serum IGF-1 concentration > 1000 ng/mL supports this diagnosis. Note: IGF-1 results may be unreliable in untreated diabetics; testing after 6 weeks of exogenous insulin is recommended. (see side bar References list – Niessen 2007)
• Cats with hypersomatotropism will require insulin dosages in excessively high ranges (2-70 U daily)

Hypoglycemia

• Potentially higher risk in tightly controlled patients
• May be associated with the onset of remission
• Signs include lethargy, ataxia, dilated pupils
• Treat with corn syrup, over the counter glucose gels/paste, or sugar water with care to avoid aspiration. Attempt to apply any treatments to the gums
• Emergency veterinary visit (requires an informed client)
• Withhold insulin until hyperglycemic again and restart with lowered dose
• Confirm there has not been overdosing or double dosing

 Somogyi Effect

• Rebound hyperglycemia as a counter regulatory response to low blood sugar
• Mediated by effects of adrenaline, cortisol, growth hormone, and glucagon
• Observed as a BG <70 mg/dL (3.8 mmol/L), followed by a steep rise exceeding 400 mg/dl (22 mmol/L)
• Documented cases are rare but if suspicions are present, 18 to 24 hour BG curves may be needed to identify

 Switching Insulin

• No wash out period required
• Start at the newly diagnosed patient dose (0.25-0.5 U/kg q12h based on lean body weight)
• Switching insulin should be considered only if duration of effect is an issue or after other troubleshooting has failed to determine a cause for uncontrolled blood sugars

Stress (Excitement) Hyperglycemia

• A particular issue in feline patients
• Blood glucose (BG) values of 144-360 mg/dL (8-20 mmol/L) may be falsely elevated due to stress
• Acute mobilization of glucose
  • BG may exceed the renal threshold (approximately 260 mg/dl [14-16 mmol/L] and result in glucosuria) 

Client Factors to Consider

• Understanding of treatment, administration/home monitoring, clinical signs, and when to call immediately
• Compliance and follow-through at home and with routine appointments
• Daily routine and household factors (travel, work/social schedules, other household pets and humans, stress of client and cat)
• Multi-cat households where it might be difficult to measure food/water intake and urine output
• Finances and resources

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© American Association of Feline Practitioners, 2019