Diabetes Mellitus
1. An understanding of the major metabolic effects of insulin and glucagon is essential in understanding some of the metabolic aberrations in diabetes mellitus.
2. Understand the classification of diabetes mellitus as defined by the National Diabetes Data Group (Robbins 5th Ed. p. 909) or (Robbins 6th Ed. p. 913). In addition, understand the clinical and biochemical definition of "impaired glucose tolerance" and "gestational diabetes mellitus."
3. Be able to differentiate between non-insulin dependent diabetes mellitus (Type 2 diabetes, NIDDM) and insulin dependent diabetes mellitus (Type 1 diabetes, IDDM) with respect to pathogenesis and presentation (Robbins 5th Ed. p. 909-915 and Table 19-3, p. 909) or (6th Ed. p. 913-918, 924-926, Table 20-3).
4. What is the pathogenesis of the two acute metabolic complications of diabetes (Robbins 5th Ed. p. 918) or (Robbins 6th Ed. p. 924-926).
5. Describe the pathogenesis of the long term complications of diabetes, especially the vascular complications (Robbins 5th Ed. p. 915-918) or (Robbins 6th Ed. p. 919-920). List the major organs involved by microvascular and macrovascular disease. Describe the morphologic changes in various organs particularly: (Robbins 5th Ed. p. 919-922) or (Robbins 6th Ed. p. 920-924)
1. pancreas
2. blood vessels, small and large
3. kidneys
4. retina
1. (Robbins 5th Ed. p. 909-922) or (Robbins 5th Ed. p. 913-926)
2. Images 1-4 and 7-8 relate to this case; Images 5-6 relate to other objectives
A 12-year-old female presents to the emergency room with fatigue, weight loss, polydypsia, polyuria, vomiting, and drowsiness. On examination she is found to have a blood pressure of 90/55, pulse rate of 110/min, cold extremities, and deep, sighing respiration (Kussmaul respiration).
Laboratory investigation at initial presentation:
|
Analyte |
Lab Value |
Reference Range |
|
urine |
glucose 4+ |
|
|
urine |
ketones 3+ |
|
|
plasma glucose |
600 mg/dL |
(65-110) |
|
sodium |
130 meq/L |
(137-145) |
|
potassium |
5.8 meq/L |
(3.6-5.0) |
|
bicarbonate |
8 meq/L |
(22-26) |
|
pH |
7.25 |
(7.34-7.44) |
|
p CO2 |
28 mmHg |
(35-45) |
|
blood urea nitrogen |
35 mg/dl |
(7-21) |
After being managed for this acute episode, the patient was treated with twice daily insulin therapy. However, 25 years later, at the age of 37, she presents to the Emergency Room with acute substernal chest pain that radiates to the neck and down the left arm. This pain lasted for at least thirty minutes and was associated with nausea and sweating. Investigations done at this point reveal that her cardiac enzymes were increased, her CK-MB was 25 (reference range 0-3 ng/ml). Her total CK was 500 U/L (reference range 38-120 U/L). An electrocardiogram revealed evidence of a myocardial infarction (ST segment changes and Q waves). After a 7 day stay in the hospital she was discharged and asked to continue insulin therapy. She was lost to follow-up but presented two years later with generalized edema. On physical examination there was no clinical evidence of cardiac failure. Neurologic examination revealed muscle weakness and loss of sensation in both lower extremities. There was also bilateral visual impairment. Examination of the retina (by an ophthalmoscope) revealed microaneurysms in retinal vessels. All of her peripheral pulses were palpable. Laboratory tests revealed elevations of blood urea nitrogen and serum creatinine (both indicating renal failure). Urine examination revealed glucose 2+ and massive proteinuria.