Troubleshooting

Note: A planned update to this Toolkit will be made in the future in order to include information about new treatments, as well as other updates.

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 the 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 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 a 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 washout 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) 

How to differentiate from true DM

  • Urinalysis – there is risk of false positive due to stress glucosuria
  • Home urine testing for glucose or have owner bring in urine sample from home
  • Home BG testing
  • Repeat testing in clinic (with pre-visit sedation, using Cat Friendly Handling, and pre-visit analgesics where pain may be causing stress)
  • Measurement of serum fructosamine
  • Plasma beta-hydroxybutyrate (>0.22-0.58 mmol/L)

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