Diabetic Emergencies
Amina Lalani
Introduction
Type 1 diabetes accounts for 5-10% of all diabetes
50% of type 1 DM present in childhood
Trend toward lower age at presentation
Pancreatic β-cell destruction results in insulin deficiency
Often associated with other autoimmune diseases: thyroid disorders, Addison’s disease, celiac disease, vitiligo
Major emergencies
Diabetic ketoacidosis
Intercurrent illness
Hypoglycemia
Complications:
Microvascular: retinopathy, nephropathy, neuropathy
Macrovascular: cardiovascular, cerebrovascular, peripheral vascular
Hemoglobin A1c: Measure of glycemic control over last 90-120 days
Canadian Diabetes Association Clinical Practice Guidelines
Insulin is given as multiple daily injections: NPH or ultralente given once or twice daily with boluses of regular insulin before meals
Recently fast-acting (insulin aspart and insulin lispro) and very long acting insulin analogs (insulin glargine or detemir) available
Use of insulin pumps is increasing: fast-acting insulin provided at a continuous rate, with boluses before meals
Table 43.1 Targets for Plasma Glucose and HbA1c | ||||||||||||
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Diabetic Ketoacidosis (DKA)
Most frequent cause of death due to diabetes in children
Risk of mortality < 0.5%
Rate of presentation in DKA ˜ 25%; more likely to present in DKA at younger age
Causes of DKA in known diabetics:
Omitting insulin dose (most frequent cause)
Infection or illness
Malfunction of insulin pump: catheter displacement
Most deaths are due to cerebral edema
Clinical Presentation
Polyuria, polydipsia, nocturia, weight loss, polyphagia, abdominal pain, vomiting
May appear as an acute abdomen
Signs of dehydration: tachycardia, decreased capillary refill, cool extremities, dry mucous membranes, poor skin turgor
Metabolic acidosis stimulates tachypnea with classic Kussmaul respirations (deep sighing respirations)
Acetone production produces fruity breath odor
Usually normal or minimal decrease in level of consciousness
Investigations
Immediate capillary glucose
Serum glucose, electrolytes, venous gas, urea, creatinine
Intravenous access
Urine for ketones and glucose
Diagnosis
Hyperglycemia: glucose > 11 mmol/L
Acidosis: pH < 7.30
Serum bicarbonate < 18 mmol/L
Ketonuria
Electrolyte Changes
Glucose:
Variable serum glucose may be due to degree of hydration
Severe dehydration results in higher glucose concentrations
Metabolic acidosis:
Increased anion gap metabolic acidosis due to ketones and lactate
Serum sodium:
Decreased due to fluid movement into intravascular space as a result of hyperglycemia
Serum potassium:
Potassium moves from intracellular to extracellular space due to acidosis, therefore serum measurements are normal
Total body potassium concentration is decreased due to urine losses
Serum potassium drops rapidly with insulin therapy
Serum phosphate:
Concentrations are normal initially but fall with treatment