Metabolic complications of Diabetes Mellitus Dr. Essam H. Jiffri

Introduction - Metabolic complications, particularly diabetic ketoacidosis and hypoglycaemia, are life-threatening and can cause permanent neurological damages. -Diabetic patients present with impaired consciousness may be caused by other conditions

Diabetic Ketoacidosis -Diabetic ketoacidosis (DKA) was responsible for 70% of diabetic deaths before the advent of insulin therapy and mortality rates are still up to 7%. -It is mainly a recognized complication of IDDM, DKA can also occur in NIDDM.

Diabetic Ketoacidosis -The clinical features of DKA result from: insulin deficiency increases in counter-regulatory hormones, produce major changes in: fuel, water and electrolyte metabolism glycogenolysis and gluconeogenesis occur.

Diabetic Ketoacidosis Increased secretion of counter-regulatory hormones leading to increased hepatic glucose output

Diabetic Ketoacidosis -Tissue uptake of glucose is reduced, contributing to the hyperglycaemia. -As glucose does not enter cells, the extracellular osmotic pressure tends to rise, causing water to transfer from the intracellular to extracellular compartment. - The renal threshold for glucose is exceeded and glycosuria occurs.

Diabetic Ketoacidosis - The presence of excess non-absorbed solute in the glomerular filtrate causes an osmotic diuresis which interferes with tubular reabsorptive function, leading to: water sodium and potassium depletion

Diabetic Ketoacidosis - Lipolysis results from insulin deficiency - NEFAs are released and transported to liver(reduced insulin and increased glucagon) leading to: greater amount of fatty acids being metabolized by beta-oxidation Acetyl CoA is exceeded and increased amount of ketone bodies

Diabetic Ketoacidosis Acetoacetate and β-hydroxybutyrate are week acids and increase H+ conc in the blood, exceeding the buffering capacity and causing acidosis - The H+ ions exchange with potassium across cell membranes, causing hyperkalaemia in some patients.

Diabetic Ketoacidosis The effect of acidosis is direct stimulation of respiratory centre by H+, causing deep hyperventilation (Kussmaul breathing)

Diabetic Ketoacidosis - A history of polyuria, polydipsia, fatigue and vomiting. - Physical signs include: dehydration tachycardia, warm skin Kussmaul respiration Odour of acetone on the breath

Diabetic Ketoacidosis Management - Diabetic ketoacidosis is a medical emergency. - The aim of treatment is to replace fluids and electrolytes, and restore metabolic control. - Patients require several liters of isotonic solution of saline to be infused, because of loss of sodium.

Diabetic Ketoacidosis Management -Intravenous insulin infusion is required, initially 6 units h-1. - Intravenous potassium may be required, the rate depending on the plasma potassium level. - Bicarbonate is sometimes infused to correct the metabolic acidosis in severely affected patients (pH 7.0).

Diabetic Ketoacidosis Monitoring Blood glucose should be monitoring hourly using test strip. Laboratory analysis of glucose and electrolytes should be done after 2h, and four hourly until the patient is stable. - Blood gases should be monitored periodaclly.

Hyperosmolar Non-ketotic Coma - Occurs mainly in elderly patient with NIDDM - Some degree of ketosis Hyperglycaemia is more severe than in DKA The condition has a high mortality rate over 50%

Lactic acidosis is usually associated with renal failure

Principal features of three forms of metabolic decompensation in diabetes lactic acidosois Hyperosmolar nonketotic coma (HONK) Diabetic ketoacidosis Features Variable Very high High Plasma glucose None present Ketosis Severe Moderate/ Acidosis Prominent Dehydration Present Hyperventilation

Long-term complication long-term complications may result from : Microvascular changes Macrovascular disease

KEY POINTS Diabetic Ketoacidosis (DKA) is a medical emergency Patients with DKA are dehydrated, sodium depleted and acidotic Plasma potassium levels should be monitored during treatment