Energy Metabolism & Endocrinology I

How can we differentiate stress-related hyperglycemia from diabetes mellitus?UA, diabetes will cause glucosuriaDoes glucagon increase or decrease glycogenolysis?IncreaseWhat stimulates release of glucagon?HypoglycemiaDoes insulin increase or decrease glycogenolysis?DecreaseWhat stimulates release of insulin?HyperglycemiaWhat is the effect of insulin on blood glucose?DecreaseWhat is gluconeogenesis?Synthesis of glucose from non-CHO sourcesWhat is the effect of glucagon on blood glucose?IncreaseDoes epinephrine increase or decrease gluconeogenesis?IncreaseDoes glucagon increase or decrease gluconeogenesis?IncreaseDo glucocorticoids increase or decrease gluconeogenesis?IncreaseWhat stimulates release of glucocorticoids?Physiologic stressDoes growth hormone increase or decrease gluconeogenesis?IncreaseWhat stimulates release of growth hormone?Fasting and vigorous exerciseDoes insulin increase or decrease gluconeogenesis?DecreaseWhat is the effect of epinephrine on blood glucose?IncreaseWhat is the effect of glucocorticoids on blood glucose?IncreaseWhat is the effect of growth hormone on blood glucose?IncreaseWhat is different about gluconeogenesis in the cat?-Some protein is always converted to glucose via gluconeogenesis -Cats cannot down-regulate this process -This is part of why cats have a high dietary protein requirementWhat happens in cats if their diet is protein-deficient?Cats will break down their own muscle protein to meet their daily protein requirementWhat is glycogenesis?Excess glucose is converted to glycogenDoes insulin increase or decrease glycogenesis?IncreaseWhat forms fructosamine?Irreversible binding of glucose to plasma proteinsWhat information does a fructosamine measurement give us?-Reflects average blood glucose concentrations over the previous 2-3 weeks -Distinguishes transient hyperglycemia from diabetes mellitusWhat do elevated fructosamine measurements indicate?Chronic hyperglycemiaName two circumstances in which it's possible to have glucosuria with a normal blood glucose.Fanconi syndrome and pyelonephritisName two circumstances in which it's possible to have hyperglycemia without glucosuria.Transient hyperglycemia and hyperadrenocorticismDoes glucosuria increase USG?YesWhen are ketones produced?During periods of intense gluconeogenesisWhat are some examples of when ketones are produced?-Fasting, starvation -Not enough energy intake and increased energy needs -Low CHO diets -Uncontrolled diabetes mellitusKetones are utilized as an energy source by what?-CNS -Cardiac and skeletal muscleWhat are the 3 primary ketones?-Acetoacetate -Beta-hydroxybutyrate -AcetoneHow are urinary ketones evaluated?-Urinary ketones present early in disease -Urine chemstrip only detects acetone and acetoacetateWhat's the most common ketone produced?Beta-hydroxybutyrateHow are serum ketones evaluated?-If ketonemia suspected, but test is negative, add 1 drop H2O2 to 1 drop of serum and retest -This will convert beta-hydroxybutyrate to acetoacetate and the chemstrip will turn positiveWhat does lactate increase with?ExerciseWhat is lactate used for?-Utilized by body tissues for energy -Gluconeogenesis: Lactate is converted back to glucoseWhat can cause excessive lactate?Hypoxia, liver failure, excessive CHO in diet (ruminants)How does excessive lactate cause acidemia?-As lactate levels rise, the number of H+ ions rise -Increased H+ in blood, decreases blood pH, resulting in acidemiaBlood lactate is used as a marker in disease monitoring. What is it a marker of?Assess global body perfusion and response to treatment in critical patientsYou're asked to take blood samples for lactate measurements in a dog receiving Lactated Ringers fluid IV. The catheter is in the right cephalic vein. What side of the dog should you take your blood sample from?Left side, opposite sideWhen taking serial measurements of a substance such as glucose or lactate, why is it important to use the same device for all measurements?Different devices may give slightly different values and you want the measurements to be as accurate as possibleWhat produces insulin?Beta cells of the islets of langerhansWhat are the functions of insulin?-Enable glucose uptake by cells in insulin-dependent tissues -Promote glycogen formation and storage in the liverWhat produces glucagon?Alpha cells of the islets of langerhansWhat is the function of glucagon?Promote hepatic glycogenolysis and gluconeogenesisWhat is diabetes mellitus?Chronically elevated blood glucose levels caused by failure of insulin production and/or insulin resistanceWhat is type I DM?Lack of insulin productionWhat is type II DM?Insulin resistance and impaired insulin secretionWhat is type III DM?Insulin resistance caused by elevations in certain hormonesName three hormones that promote insulin resistance.Glucocorticoids, growth hormone, progesteroneWhich of these hormones is elevated in hyperadrenocorticism?GlucocorticoidsBecause glucocorticoids are elevated, most cats with hyperadrenocorticism (and some dogs) also have which other disease?Diabetes mellitusAn elevated blood glucose with glucosuria is diagnostic for what disease?Diabetes mellitusIn DM, what does the presence of urine ketones indicate?Diabetic ketoacidosisA patient in the ER where you work has the classic "DKA breath." But her urine tested negative for ketones. What test is run to detect ketonuria (i.e., which part of the urinalysis)?Chemical evaluation (chemstrip)Could this patient still have ketosis? Why or why not?Yes, urine chemstrip does not detect beta-hydroxybutyrate ketonesWhat additional test can you do to detect ketonemia?Serum ketonesWill serum ketone test work to detect ketonuria?No, ketonemia occurs before ketonuriaWe usually recommend running a urine culture and sensitivity in newly-diagnosed diabetics. Why?To test for UTI because diabetes impairs immune defenses and glucosuria makes urine an even better bacterial mediumWe also usually recommend running a urine culture and sensitivity in animals with newly-diagnosed hyperadrenocorticism, even when the urine sediment is normal. Why?They have increased cortisol levels, which weakens the immune system and puts them at higher risk for UTIsWhat is the goal of insulin therapy in small animals?Keep BG at 100-200 mg/dl for as much of every 24-hr period as possibleWhy is insulin therapy important?-Keep BG below the renal threshold to prevent PU/PD -Enable cells to utilize glucose to prevent hyperglycemia, weight loss, and ketonesAn animal is dropped off at the practice for a serial blood glucose curve. Is the insulin usually given at home, or at the practice?At homeHow often are blood glucose measurements taken for serial blood glucose curves?Every 2 hrsFor how long are blood glucose measurements taken for serial blood glucose curves?A minimum of 12 hrsShould the animal have access to water during serial blood glucose curves?Yes, but no foodWhat information does a serial blood glucose give us about the insulin therapy for an individual patient?Allows us to determine correct insulin type, dose, and frequencyRepeat serial blood glucose curves aren't scheduled sooner than 7 days after any change in insulin therapy. Why?The patient's metabolism needs to adjust to the change; a BGC sooner than 7 days is usually not accurateWhy don't we usually use fructosamine tests to regulate newly-diagnosed diabetics?It doesn't give us hourly blood glucose changesYou're doing a serial blood glucose curve on a diabetic patient. The patient's latest blood glucose measurement is 58. What is the first thing you should do?Notify DVM immediatelyWhat are CVT responsibilities when an owner opts to perform BGC at home?-Train owner in sample collection, BG measurement, BGC protocol, and quality control -Help owner troubleshoot if questions/problems ariseWhy is it important to always use the same device when performing a serial blood glucose?Measurements must be consistent in order to be accurateCan a patient undergoing a serial BGC be fed? Why or why not?No, avoid post-prandial hypoglycemiaObesity and laminitis (with an insidious onset) are seen in which equine disease?Equine metabolic syndromeWhen testing a horse for IR/EMS, why do we need to take simultaneous BG/insulin measurements?Elevated insulin with normal BG in the same blood sample is diagnositcWhat is the purpose of the oral sugar test?If a bolus of glucose is given orally to horses with EMS, this will stimulate an exaggerated insulin responseIs the oral sugar test a dynamic test?YesWhy should insulin measurements and the oral sugar test not be performed in horses with active laminitis?-Pain and stress will increase insulin levels -Glucose bolus can exacerbate active laminitisWhat is insulinoma?Tumor of the pancreatic beta cells that cause excessive secretion of insulin, resulting in persistent hypoglycemiaWhen testing a dog suspected of having an insulinoma, why do we always check a serum BG prior to sending blood samples to the lab?Patient must be hypoglycemic (BG <60 mg/dl)How is insulinoma diagnosed?Decreased BG with increased insulin in the same serum sampleHow is insulinoma confirmed?-Ultrasound/CT -Exploratory laparatomy