The Case: Unwell Diabetic Cat After Boarding

HISTORY/PRESENTATION

A 12-year-old castrated domestic short haired cat was admitted for boarding for 5 days. He weighed 13.15 lb at admission and was being treated with glargine insulin (1 U q12h SC) for diabetes mellitus and with fluoxetine (10 mg q24h PO) for behavioral issues. During his stay he exhibited a decreased appetite for canned Purina DM and chicken but a good appetite for dry food. He was vocal and friendly during daily physical examination and no abnormalities were noted. Cat was discharged without incident.

EMERGENCY PRESENTATION

The cat was presented emergently for lethargy, vomiting, and decreased appetite the following evening. He had received glargine insulin (1 U q12h SC) and fluoxetine the evening of discharge.

Physical Examination

The patient was quiet, alert, and responsive.

• Weight: 12.4 lb  

• Temperature: 100.5⁰F

• Pulse: 200 bpm

• Respiration: 50 bpm

• Hydration: 6% dehydrated

• Mucous membranes: Pink, slightly tacky

• Abdominal palpation: tense and painful, particularly cranially

Diagnostics

Blood

• Packed cell volume/total protein: 42%/8.4 g/dL (ranges, 28-47/5.7–8.6)

• pH: 7.15 (range, 7.35–7.45)

• Sodium:  148.2 mEq/L (range, 145–158)

• Potassium: 2.94 mEq/L (range, 3.4–5.6)

• Chloride: 116 mEq/L (range, 104–128)

• Glucose: 291 mg/dL (range, 64–170)

• Lactate: 0.8 mmol/L (range, <2.5)

• Blood urea nitrogen: 28 mg/dL (range, 14–36)

• Creatinine: 1.6 mg/dL (range, 0.6–2.4)

Urine

• Urine specific gravity: > 1.050 (range, 1.015–1.060)

• pH: 6.5 (range,  5.5–7.0)

• Ketone: 160 (normal, negative)

• Glucose: 500 (normal, negative)

Treatment

The patient was hospitalized for management of diabetic ketoacidosis and treatment of presumptive pancreatitis. 

• Plasmalyte* (6 mL/kg/hr) + potassium chloride (20 mEq/L) + potassium phosphate (20 mEq/L)

• Insulin loading: monitor blood glucose q1h; administer regular insulin (1 U q1h IM) until value is <250

• Cisapride: 2.5 mg q12h PO

• Ranitidine: 3.5 mg/kg q12h PO

• Ampicillin/sulbactam: 30 mg/kg q8h IV

• Maropitant: 1 mg/kg q24h PO

• Buprenorphine: 0.02 mg/kg q12h transmucousally

Progress/Outcome

Electrolytes 

Day 2

• Chloride: 109 mEq/L (range, 104–128)

• Phosphorus: 1.8 mg/dL (range, 2.4–8.2)

• Potassium: 2.4 mEq/L (range, 3.4–5.6)

• Sodium: 157 mg/dL (range, 145–158) 

→Increased potassium phosphate to 40 mEq/L

Day 3

• pH: 7.383 (range, 7.35–7.45)

• Phosphorus: 7.2 mg/dL (range, 2.4–8.2)

• Potassium: 7.0 mEq/L (range, 3.4–5.6)

• Sodium: 161 mg/dL (range, 145–158)

→Iatrogenic hyperkalemia; decreased potassium chloride in IV fluids

Day 4

• Chloride: 109 mEq/L (range, 104–128)

• Potassium: 3.6 mEq/L (range, 3.4–5.6)

• Sodium: 158 mg/dL (range, 145–158)

 →Supplemented potassium chloride in IV fluids

Serum chemistry/Complete blood count

Day 3

• Alanine aminotransferase: 202 IU/L (range, 10–100) 

• Packed cell volume/total protein: 41%/7.8 g/dL (ranges, 28–47/5.7–8.6) 

• Total bilirubin: 0.8 mg/dL (range, 0.1–0.4)

Blood Glucose (range, 65–155)

Day 3

• 410, then 316 

Day 4

• 420

Day 5

• 414 

Day 6

• 339

Urine Glucose/Ketone

Day 4

• 2000/small (normal, negative/negative)

→Insulin switched to glargine (2 U q12h SC) on Day 5

Outcome

Patient was eating well on Day 6. On Day 7 he was transferred out of emergency services, recovered well, and was discharged. 

*Plasmalyte is a multiple electrolyte isotonic IV solution.

The Generalist’s Opinion

Barak Benaryeh, DVM, DABVP

Diabetic ketoacidosis (DKA) is a disease state that every general practitioner will encounter. This cat’s DKA was likely brought on by the boarding episode, which may have triggered a bout of pancreatitis. The practitioners did a very good job of quickly identifying the problem and instituting appropriate treatment. The case serves as a reminder and cautionary tale about our boarding patients: it does not take much for patients with diabetes to destabilize.  It is also a good review for treating both pancreatitis and diabetic ketoacidosis.

Cats & Boarding

People often choose to entrust their diabetic cats to a boarding facility connected to a veterinary hospital so that they can be properly managed should any complications arise. All boarding facilities should have a monitoring system in place for recording appetite, urination, defecation, and general attitude. If glucose levels are not being monitored, there is no way to know if appropriate insulin levels are being administered. Blood glucose should be measured just prior to insulin administration during the first day or two of boarding, which will provide an idea of whether the dose needs to be adjusted without requiring an entire curve. It is by no means definitive, but if readings are exceedingly high or low, the cat's stress may be having a significant effect and more careful monitoring is needed. 

Clients should be informed that this is to ensure appropriate administration of insulin and that there will be a charge for the service. It’s not uncommon for insulin requirements to change in a boarding situation. If glucose levels are not being monitored, there is no way to know if appropriate doses are being given. This cat was on fluoxetine, so there must have been some pre-existing behavioral issues and any potential anxiety or stressor can change insulin needs.

Diabetic Ketoacidosis: Treatment 

The clinicians used an intramuscular (IM) insulin protocol. There have been some studies comparing the IM route to an intravenous constant rate infusion (CRI).^1,2 Both are considered appropriate methods, although clinician preferences and comfort levels vary between them. In more critical cases, there is likely a benefit to using an insulin CRI though to my knowledge there are no studies that address this issue specifically. The cat in question was relatively stable, and using the IM protocol was clearly effective.

Insulin therapy appears to have been instituted immediately. It is generally safer to delay insulin therapy by 4 to 6 hours when managing diabetic ketoacidosis, until after fluid therapy has been instituted. Insulin administration can trigger movement of glucose and water from the intravascular to the intracellular space and, if instituted too quickly, can potentially lead to further complications such as shock.²

Feline Pancreatitis

A presumptive additional diagnosis here, made on the basis of pain in the cranial abdomen, was pancreatitis, and it is common among cats with DKA to have concurrent or predisposing illnesses.³ We are not given the values for any of the pancreatic enzymes. Whether the values were normal or elevated, however, does not rule in or out the possibility of pancreatitis. An abdominal ultrasound (although also not completely reliable) would have been a helpful test in determining a diagnosis. Ultimately, diagnosing feline pancreatitis is difficult. Instituting treatment based on suspicion, as was done in this case, is often the only option.

The Specialist’s Opinion

Gretchen Statz, DVM, DACVECC

Medical boarding is commonly offered by veterinary clinics to accommodate patients that are not quite healthy enough for a regular boarding facility. Medical boarders are generally considered stable and are not always assessed as often or as thoroughly as other hospitalized patients. They are sometimes kept in the back of the clinic and not observed as closely as patients in an ICU setting. This case demonstrates the importance of doctor assessments of medical boarders on at least a daily basis. It is important to keep records of appetite, urinary and defecation habits, and ideally body weight (especially for longer stays). All notes from these daily assessments and nursing assessments should be part of the animal’s medical record. In this case, daily assessments were made and changes in appetite were noted; however, the pet did not show clinical signs until it arrived home.    

Diabetes mellitus can quickly become a frustrating and potentially life-threatening disease. Seemingly stable diabetic patients can have unexpected changes in glucose regulation and insulin needs without much warning, which can lead to a hypoglycemic crisis or diabetic ketoacidosis (DKA). These potential complications make it especially important to closely assess diabetic patients during boarding. Such animals also need to be kept on their normal feeding and insulin schedule as much as possible. Changes in food intake and insulin schedules can easily disrupt diabetic regulation. In this case, the cat was assessed on a daily basis and no obvious changes were noted. He did have a change in eating from canned food to dry. It is possible that this change and/or the stress of boarding precipitated his decline.

Workup for DKA 

In patients with DKA, it is ideal to look for a reason for the change in diabetic regulation. A urine culture and abdominal ultrasound can be helpful in these situations to observe for evidence of pancreatitis or urinary tract infection (both common in diabetics). This patient was assumed to have pancreatitis based on the presented abdominal pain and other clinical signs and was treated with antibiotics. It is not mentioned whether further diagnostics were offered.

Bloodwork & Fluid Therapy 

Some of the more classic bloodwork changes associated with DKA, including hypokalemia and hypophosphatemia, were present. Both potassium and phosphorus often drop when insulin is initiated, so it is important to monitor electrolytes closely and to treat relatively aggressively. Potassium did drop initially in this case but was treated accordingly, and eventually the potassium level was corrected. Sodium increased with treatment, likely indicating free water loss and dehydration. It is possible that in the beginning the patient was not treated aggressively enough with IV fluids. Animals with DKA often require high fluid rates to correct dehydration and to keep up with ongoing losses.

Options for Insulin Therapy

Animals with DKA are most often treated with short-acting insulin (Humulin R), which can be administered via intermittent intramuscular injections or a continuous rate infusion (CRI). The blood glucose levels in this case remained relatively high, never dropping below 250 mg/dL. A CRI of insulin may have been more effective at achieving normoglycemia and keep levels stable. Insulin CRIs do require 24-hour care by experienced staff.