Answer 1
A history of alcohol consumption should be obtained, in addition to a history of diabetes, the level of diabetic control and a past history of diabetic ketoacidosis. While diabetic ketoacidosis is traditionally found in Type I diabetics, students should understand that ketoacidosis can occur, albeit infrequently, in Type II diabetes if a patient has been poorly controlled and a complicating factor is present such as sepsis, acute myocardial infarction, etc. Hyperosmolar coma is associated with Type II diabetes and is usually seen in the clinical setting of a patient who has been controlled with diet and/or oral agents (or occasionally with low dose insulin) who is unable to obtain free access to water or other fluids and becomes dehydrated. This is typical of a nursing home patient, or a confused or demented elderly patient who does not sense thirst appropriately. The clinical scenario for lactic acidosis is usually seen in the setting of underlying sepsis, poor cardiac perfusion (such as in a myocardial infarction or severe congestive heart failure), or in individuals with underlying renal insufficiency taking medications such as biguanides, which can aggravate their renal disease.
In addition to the history, the physical exam is also very important and the students should know to pay close attention to the respiratory rate, the possibility of Kussmaul breathing, and to the odor of the patients breath (a fruity odor is suggestive of ketones). Signs of sepsis should be watched for, in addition to underlying poor cardiac perfusion, i.e., CHF, pulmonary edema, etc. Also to be discussed is the role of measuring a serum glucose, B-OH butyric acid level, and a pH to determine the severity of the acidosis.
Answer 2
The biochemical consequences of failure to take insulin include hyperglycemia, hyperlipidemia, and the build up of ketone bodies. Treatment for ketoacidosis should involve starting an insulin infusion with: (1) an initial bolus dose based on the patient’s ideal body weight (IBW) (.1 units/kilo IBW), and (2) the institution of an insulin drip at a rate also based on the patient’s IBW (.1 units/kilo IBW/hr). If the blood sugar fails to decline after one hour of therapy, the patient should be rebolused and the rate should be increased (both by approximately 50% of initial dose). IV fluids should be initiated with normal saline if the patient has a normal cardiovascular exam, or half-normal saline if there is any question of the patient’s underlying cardiac status. Serum potassium should be obtained and monitored closely - once it is known that the patient is not oligouric, potassium should be added to the IV, usually at a dose of 40 mEq/L. While other types of insulin regimens have been employed, including subcutaneous and intramuscular insulin injections, the IV insulin infusion rate is preferred as this most physiologically lowers the blood sugar and leads to less hypokalemia. When the patient’s blood sugar has dropped below 200 mg/dl, the IV fluids should be changed to D5 with normal (or half-normal) saline. When the patient has been medically stabilized, which is usually within 12-16 hours, the patient should be changed to subcutaneous insulin injections, either utilizing the patient’s usual dose of insulin or calculating the patient’s total insulin requirements from the previous 24 hours and giving 2/3 of that total dose as intermediate-acting insulin (NPH or Lente) and 1/3 as a fast-acting insulin (Humalog or regular insulin). Finally, the dose of both the intermediate and fast-acting insulins should be split to 2/3 in the morning and 1/3 in the evening. This issue will be further addressed in question 10.
Anwer 3
The patient’s proteinuria may be an indicator of underlying diabetic nephropathy and this should be examined by having a 24 hour urine for creatinine clearance and protein excretion performed during the patient’s hospitalization. An angiotensin converting enzyme inhibitor should be started, as there is clear documentation that ACE-inhibition leads to a decrease in proteinuria and improvement in creatinine clearance. The degree of renal insufficiency often correlates with diabetic eye disease and the patient needs an ophthalmologic exam.
Answer 4
The patient’s hypothermia may suggest underlying sepsis, hypothyroidism (found with a greater incidence in patients with Type I diabetes, or cold exposure. While hypoglycemia can also lead to a decrease in core body temperature, that is not the problem in this patient.
Answer 5
The students should be able to discuss other possible explanations for the patient’s failure to regain consciousness, including the need to examine his calcium, magnesium, phosphorus levels, in addition to a possible subdural in this alcoholic individual who has lost consciousness.
Answer 6
The students should be apprised of the fact that individuals with Type I diabetes have a higher incidence of early coronary disease. While there is data to suggest that hyperinsulinemia of and by itself may be an independent risk factor for accelerated coronary events, this issue is still controversial and more germane to patients with Type II diabetes. In addition to coronary disease, individuals with diabetes have a higher incidence of accelerated peripheral vascular disease.
Answer 7
Included with this facilitator’s guide will be an algorithm for the initial regular insulin rate for diabetic patients undergoing CABG. It is based on the patient’s prevailing blood sugar and total dose of insulin prior to surgery. The students will also be given an IV insulin protocol for non-cardiac surgery. This information is also included in Reference 3. It is essential that the facilitators drive home the teaching point that diabetic patients undergoing surgery will require more insulin when undergoing CABG surgery than any other type of procedure.
Answer 8
Complications of diabetes which should be considered in the pre-operative assessment and post-operative management include presence and degree of retinopathy, neuropathy (especially autonomic neuropathy with gastroparesis preventing a great challenge to the clinician managing the patient) and underlying renal disease in addition to underlying cardiac and peripheral vascular disease. Also, a past history of hypertension should be addressed.
Answer 9
The patient’s headaches and early morning nightmares may reflect hypoglycemia between 2-3:00 a.m. The patient should be told to set an alarm clock and monitor his blood sugar at this time to confirm this problem. The patient’s fasting sugar, which is elevated, may reflect the Simogy effect with rebound from earlier hypoglycemia. This is also an excellent time for the facilitators to discuss with the students the peaking times of insulin administration, highlighting the fact that NPH taken at supper time, as this patient was doing, can lead to hypoglycemic problems at 2-3:00 a.m. For this reason, patients are often told to split their second injection, taking Humalog or regular insulin for dinner and moving their NPH to bedtime. This will allow the NPH to peak approximately 8 hours later and cover the surge of glucose produced by hepatic gluconeogenesis under the stimulation of growth hormone and cortisol, helping to smooth out their fasting blood sugar control and averting the problem of early morning hypoglycemia.