Nursing the Diabetic Patient Nicola Ackerman BSc(Hons) RVN CertSAN CertECC A1 V1 C-SQP HonsMBVNA

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1 Diabetes. Diabetes mellitus is a complex disease, with stabilisation of blood glucose levels being affected by confounding disease processes, efficacy of the primary disease control treatment, diet and exercise programme and weight control. Thus a full history of the animal, including all these factors must be taken. There are several possible causes of diabetes mellitus, including pancreatitis, obesity, drugs (glucocorticoids, progestins), concurrent illness (hyperadrenocorticism, acromegaly), genetics, immune-mediated insulitis, infections and Islet amyloidosis. Obtaining an ideal body condition score in both cats and dogs is the ideal goal in all of these cases, with obesity increasing the risk of non-insulin dependent diabetes mellitus (NIDDM) in cats by fourfold. Obese diabetic animals may have difficultly losing weight, but stabilisation of the diabetes is the initial aim, followed by a conservative weight loss programme, which does need to be carefully monitored by a veterinary professional. Underweight animals once stabilised should be fed a modest increase in calories in order to promote repletion. Dietary therapy can only help to improve glycaemic control, but emphasis should be placed on adjustment of the insulin (or oral lypoglycemic not commonly used due to efficacy) dosage and schedule, and control of concurrent disease. 1 With IDDM, the beta cells within the pancreas lose their ability to secrete insulin. This can be congenital or as a result of pancreatitis, or prolonged disease to the pancreas. Exogenous insulin administration is required as the treatment. The monitoring of pancreatic specific enzymes should also occur when conducting routine monitoring of these cases, as it can be a primary cause. NIDDM is defined as insulin resistance occurring at the site of the peripheral tissues. Dysfunction of the beta cells can also be a causal factor of NIDDM, (Figure 12A). The quantity of insulin secreted by the beta cells can be increased, decreased, or can remain normal. In some texts Type 2 diabetes, which resolves is sometimes classed as transient Type 2 NIDDM. This is more commonly noted in obese cats when insulin resistance becomes established. Once the cat obtains and then maintains an ideal body condition score, NIDDM can resolve itself. If the beta cells also become exhausted; a period of exogenous insulin administration may be required. The beta cells can start secreting insulin after a period of time, and therefore is not a true NIDDM. Hyperglycaemia is toxic to beta cells and aggravates the situation by further reducing insulin secretion. This mechanism can also explain why the more obese the animal and the longer that this animal has been obese the greater the incidence of the onset of diabetes. There are many factors that can predispose the animal to insulin resistance; these are detailed in Table 16B. Performing Serial Blood Glucose Tests. Serial blood glucose testings are useful for the monitoring of insulin therapy in dogs, and initial assessment of the response to insulin in cats. When initiating insulin therapy

2 serial blood glucose levels should be monitored every two hours. The purpose of the monitoring is to establish whether the insulin is effective, length of effectiveness and time of nadir. There is a tendency when performing serial blood glucose tests to plot a graph and join up the dots. This can lead to misinterpretations of graphs, as if tests are two hours apart, glucose levels can be lower or higher than expected and not on the line drawn between two readings. Serial blood glucose testing is difficult in cats, and it has been shown in cats that even on consecutive days serial blood glucose testings would have caused two very different conclusions in what the veterinary surgeon would have interpreted the results and altered the insulin levels. More accurate levels can be achieved through monitor blood glucose levels at home. Any changes in insulin should be performed slowly, and only by half a unit every 7-10days if required. It takes the body over a week to adapt to insulin level changes and therefore more rapid changes can be detrimental. Diabetic Ketoacidosis. Diabetic Ketoacidosis (DKA) can arise in an animal with previously diagnosed diabetes mellitus (DM) or it can appear to occur suddenly in an animal that the owner thought to be healthy. For DKA to develop there is usually a triggering condition, as shown in the table below. This triggering condition then causes the glucagon:insulin ratio to increase. Glycagon promotes glycogenesis and the formation of ketoacids. Insulin is also required for metabolism of ketones to carbon dioxide and water. When there is a low level of ketone production in uncomplicated DM, the ketones can be metabolised and do not build up to the point of which they cause clinical signs. Bacterial Infections Any significant infected focus but especially: Urinary tract infection upper and lower Prostatitis Pneumonia Pyoderma Otitis externa

3 Severe gingivitis/oral abscesses from tooth root infections Inflammatory Disease Pancreatitis Endocrinopathies or physiological endocrine changes Hyperadrenocorticism (cats and dogs) Acromegaly (cats and dogs, though different mechanisms) Hyperthyroidism (cats) Hypothyroidism (dogs) Phaeochromocytoma Dioestrus phase of oestrus cycle Iatrogenic causes Steroid therapy including intra-aural or ocular Table: Conditions that can trigger DKA through insulin resistance. Initial Assessment of DKA Patients. The initial assessment of these patients needs to completed as rapidly as possible. Parameters to be measured include: o Packed cell volume (PCV) alongside total solids/proteins o Electrolytes o Renal function assessment urea, creatinine and phosphorus o Blood gas analysis o Urine analysis Specific Gravity Dipstick analysis assess for ketones Sediment examination Submit for culture

4 Blood serum ketones should be tested for, but many practices don t have the facilities in order to do this. Urine dipsticks can be used to measure ketone levels, but do not measure the most predominant ketone body (β- hydroxybutyrate). Therefore false negatives can be seen. The addition of hydrogen peroxide to the sample to oxidise the β-hydroxybutyrate to acetoacetate will enable the urine dipstick to measure all of the ketone bodies. Management of DKA Patients. The initial management of DKA patients is to provide insulin in order to reduce the hyperglycaemia and promote ketone metabolism whilst correcting the intravascular volume, correcting hydration levels and any electrolyte imbalances. Insulin Therapy. The main therapy for DKA patients is through insulin, and this can be achieved in two different formats dependant on the equipment that is available in practice. Intramuscular Insulin: Begin treatment with 0.2IU/kg intramuscular bolus of neutral (soluble/regular) insulin. Repeat intramuscular injections of 0.1IU/kg hourly according to blood glucose measurements, measurements need to be kept within 8-15mmol/l. If the blood glucose drops below 8mmol/l, add 5% dextrose to the intravenous fluids, monitor blood glucose and continue insulin therapy if possible. Use neutral/soluble/regular insulin for the initial therapy or until the animal begins to eat reliably. Once eating the animal can be changed onto maintenance stabilisation using a longer-acting insulin. Intravenous Constant Rate Infusion (CRI): Mix the neutral/soluble/regular insulin with fluids such that it will be delivered at a dose rate of 2.2IU/kg/day. Use of a syringe driver or fluid pump needs to be used in order to have accurate administration of the insulin. A flow rate of 1-2mls/kg/hr can be administered for the insulin, and addition fluid therapy can be run alongside. The insulin mixture needs to protected from light, covered with aluminium foil, or bandage, and freshly made up every 24hours.

5 As insulin binds to plastic tubing in drip lines, prior to administration the fluid mixture needs to be run through the line until a stable solution has been achieved (30-50mls expelled). Blood glucose needs to be checked after 1hour then every 1-2 hours thereafter. Dextrose can be used as required to maintain the blood glucose between 8 and 15mmol/l. Long acting insulin can be introduced when the animal starts to eat. Clinical Nutrition of Diabetic Patients. Water. A clinical symptom of diabetes mellitus is polydipsia (PD) and polyuria (PU). Obligatory losses of electrolytes, such as sodium, potassium, chloride, calcium and phosphorus and the water-soluble vitamins will occur. Access to fresh water at all times is required, and in severe cases administration of parenteral fluid may be required. Monitoring fluid intake, if possible, is a good indicator of glucose control, and insulin effect. Diabetic diaries are a good idea, and if owners can comment on daily water consumption this can be helpful when stabilising patients. Proteins. Protein levels with diabetic dogs may need to be increased, especially in the quality of the provided proteins. This is due to losses of amino acids in the urine, a consequence of renal glomerulopathy, or changes in hormonal signals. Excess protein levels need to be avoided, as renal damage can be enhanced. In cats the protein and carbohydrate balance is an important factor in the clinical nutrition of diabetic cats. Carbohydrates. Consumption of soluble or simple carbohydrates is the primary cause of rapid postprandial hyperglycaemic spikes. Diets need to avoid high levels of soluble carbohydrates and the feeding of treats high in soluble carbohydrates should be stopped. Use of insoluble carbohydrates, fibre, has a positive effect on glycaemic control in dogs and cats. Diets that contain fibre, which exerts gelling properties,

6 have an ability to slow the rate of presentation of nutrients (including glucose) to the body. This helps reduce the postprandial spike. The fermentation products of fibre, short chain or volatile fatty acids, also modify the secretion of some of the digestive hormones and the sensitivity of tissues to insulin. Complex carbohydrates should provide ~50-60% of the calories in diets for dogs, and in situations where cats are being fed a high fibre diet. 1 Felines are obligate carnivores, and have a unique metabolism. Initially, feeding a growth diet was the diet of choice, due to the relative protein increase and decrease in carbohydrate content. Specific diets aimed at diabetic cats are widely available, in cases where owners are unable to afford a prescription diet, a good quality kitten diet can still be recommended. A decrease in carbohydrate content will also create an increase in DM% of fat content (Table 16C). A high protein, low carbohydrate diet has shown to enhance insulin sensitivity. Monitoring of blood glucose levels should be monitored after dietary introduction as hypoglycaemia can result. This combination of high protein, low carbohydrate closely resembles the natural diet of a cat in the wild. In studies examining this dietary therapy have shown that insulin treatments could be discontinued in 15 out of 24 cats. 3 Vitamins and Minerals. Polyuria (a common clinical symptom of diabetes) will increase the loss of electrolytes and water-soluble vitamins, with magnesium and phosphorous are being the most significantly lost. Chromium can be used to improve peripheral insulin sensitivity and glucose tolerance, though accurate studies on the use of chromium have not been conclusive. Vanadium, when dosed in pharmacological amounts has insulin like effects, though vanadium does cause gastrointestinal side effects, and chronic excessive intake may have toxic effects. Feeding an Insulin Dependent Diabetic Pet. On diagnosis of diabetes mellitus, dramatic changes to the animal s diet can be contraindicated. A high carbohydrate diet should be avoided, as should semi-moist diets. These diets have a hyperglycaemic effect due to the increased levels of simple carbohydrates and other ingredients used as humectants (e.g. propylene glycol). Cost does play a deciding factor in choosing a diet for a diabetic patient, as does whether or not the animal eats the food. High fibre diets are exceptionally useful in aiding stabilisation of glucose control in dogs, but if the dog is unwilling to consume adequate amounts this can be detrimental to the animal. An underweight animal will need a modified diet in order to gain weight, but this can only be achieved with insulin therapy. Administration of exogenous insulin does need to be coordinated with times of feeding. Insulin regimes, whether insulin is being administered once or twice daily,

7 will have a large effect on quantities being fed at each mealtime. If injected once daily, half the food should be fed at time of injection, the remainder eight to ten hours later. Twice daily injections require meals containing half the daily calorific intake at the same time of insulin administration. The owner needs to be aware of the detrimental effects of feeding snacks and treats between meals. Milk should also be avoided due to the calorific intake. Timing of meals is not as critical in feline diabetic patients, and it is advised to continue feeding the cat in the way that it is use to (e.g. ad libitum). Cats that are fed set meals should receive one third of the daily food requirement at the time of administration of the insulin. The remainder of the diet should be fed at the estimated peak action time of the insulin (when the nadir occurs); this does differ for each animal. In cases of hypoglycaemia the owner can administer dextrose gels (Hypo-stop gel), or honey, jams or syrups to the mucous membranes of the mouth. This should only be recommended on advice from the veterinary surgeon once the owner has contacted the veterinary practice, or the blood glucose level has been measured. Use of an at home glucometer can be exceptionally useful, but obtaining sufficient blood for a test during a hypoglycaemic episode can be very difficult. This is due to a constriction of the peripheral blood supply, and in more severe cases shaking or convulsions. Depending on glycaemic control smaller frequent meals may prove to be more beneficial in obtaining control. The use of mini-glucose curves in establishing nadir, length of insulin action and dietary effect are invaluable. Feeding a Non-Insulin Dependent Diabetic Pet. Many cats that present with NIDDM are obese. A controlled weight loss programme is required in these cases. Predisposition to hepatic lipidosis during rapid weight loss is of concern in cats. Once an ideal body condition score has been achieved in these animals, and glucose levels remain stable it is important that these animals receive regular checkups, including weighing and fructosamine levels. Use of a higher fat and protein, decreased carbohydrate diet has proved to be very useful in cats suffering from NIDDM. The choice of diet will also depend on any secondary medical conditions. Renal dysfunction is commonly experienced when there has been a persistent hyperglycaemia. A low salt diet would be a more preferable choice, but care should be taken as these diets have higher carbohydrate content due to a restriction in protein levels. Anaesthesia Protocols for Diabetic Patients. Management of blood glucose concentrations is the most important consideration when anaesthetising patients with diabetes mellitus. Stable diabetic patients that are to under a procedure under anaesthesia should be recommended to give a half dose of insulin on the morning of the procedure. The procedures should be scheduled so

8 that the diabetic patient is the first procedure of the day, so that it can be fed post procedure as soon as possible. Pre-medication and use of alpha-2 agonists should be avoided as they cause an elevation in blood glucose during the procedure, and once reversed a refractory decrease in blood glucose level. Very careful monitoring needs to be utilised if alpha-2 agonists are therefore used. Following pre-medication a blood glucose sample should be taken for a baseline level. If the patient is already hypoglycaemic (blood glucose <4mmol/l) then intravenous glucose should be administered. Throughout the procedure if the blood glucose drops below 4mmol/l, administration of glucose should be instigated. Intravenous glucose is highly irritant, and should be given diluted with saline or water. Supplementation is more effective when a loading dose is given followed by a continuous rate infusion. This will help reduce any peaks or troughs in blood glucose levels. On recovery from anaesthesia, monitoring of blood glucose should occur until the animal has recovered fully to in order to eat. A highly digestible (low fat) diet should be offered. Protocols for Nursing Diabetic Clinics. Having a protocol for the diabetic clinic can be useful. Having a checklist to run through can aid the veterinary nurse in ensuring that all points have been covered, and specific notes can be added where greater clarification is required by the owner. 1.) All newly diagnosed diabetic cases should be discharge by the Diabetic care nurse, with a minute appointment allocated. 2.) Subjects to discuss with owner include, how to give injections, storage of insulin, disposal of sharps and monitoring of the animal. This includes polydipsia and polyuria, appetence levels, lethargy, activity levels, how to identify hypoglycaemic episodes. The treatment of hypoglycaemic episodes and what to do if the owner is worried at any point should be covered. Symptoms of hypoglycaemia include, but don t necessarily mean that all will be noted but the owner: Polyphagic Weakness/lethargy Disorientation Ataxia Strange behaviour, e.g., aimless wandering (sometimes noted as being

9 vacant), searching for food, licking lips Severe neurological signs, e.g., collapse, convulsions, loss of consciousness and eventually death 3.) If required the process of home monitoring can be discussed, and the owner shown how to use a glucometer. A second appointment can be made to cover this subject if the owner wants to have two consultations as it can be a large amount of information to take on board in one session. Having client literature or DVDs on this subject can be useful for the client to take away and view initially prior to having the second nurse consultation. 4.) Discuss how the diabetes stabilisation programme works. Explain why the insulin levels are only increased once every 7-10days in small increments followed by glucose curve until correct dose reached. Explain to the owner that it can take a long time, so that they are not disheartened if it does take a while to stabilise. 5.) Discuss exercise regimes and feeding levels and timings. It can also be useful to discuss what to do if the animal is unwell, or has not eaten all of it s diet. Again, it can be a little over whelming for owners with newly diagnosed animals to have all of this information. Splitting up of the information into two consultations a week apart can prove to be useful. 6.) Discuss the type of diet the animal is receiving. If the pet is already receiving a good diet, then it can remain on the diet. If not, this includes semi-moist diets; the animal s diet does need to be changed. Semi-moist diets are higher in simple sugars and can cause higher post-prandial hyperglycaemic spikes than any other diets. Ideally the pet should transition onto a diet specifically designed for diabetics as this can have several benefits. 7.) Ensure that the owner has business card/contact details of the diabetes nurse in charge of the case. Having a named nurse can greatly increase compliance, and ease any worries that the owner may have. Ensure that the owners are aware that in an emergency not to wait until the diabetic nurse is next on duty, but to phone the practice as soon as possible. The use of s can be just as helpful as a phone number in order to contact the diabetic nurse. 8.) Fill out diabetes care sheet, and explain to the owner how to fill out the diabetes diary. This is very helpful if more than one person is caring for the animal, so that the pet isn t accidentally injected more than once. Having written instructions is very important with all new cases. 9.) The diabetes nurse in charge of the case should contact the owner for the first couple of days to ensure that the owner is happy with injecting insulin. If not, the owner and pet can come to the practice for the first few injections with the nurse present to aid if required.

10 References. 1. Michel KE. Nutritional management of endocrine disease. In: Ettinger SJ and Feldman EC, eds. Textbook of Veterinary Internal Medicine Volume 1 6 th Edition. Missouri: Elsevier Science; 2005: 2. Stogale L. Definition of diabetes mellitus. Cornell Veterinarian. 1986; 76: Mazzaferro EM, Greco DS, Turner AS and Fettman MJ. Treatment of feline diabetes mellitus using an a-glucosidase inhibitor and a low carbohydrate diet. J feline med and surg. 2003; 5(3). Further Reading. BSAVA Manual of Canine and Feline Emergency and Critical Care. Second Edition (Ed): King L.G. and Boag, A.