Metabolic complications of Diabetes Mellitus

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Metabolic complications of Diabetes Mellitus

• Dr. Essam H. Jiffri

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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

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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.

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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.

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Diabetic Ketoacidosis

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

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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.

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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

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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

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Diabetic Ketoacidosis

• Acetoacetate and ß-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.

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Diabetic Ketoacidosis

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

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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

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Diabetic KetoacidosisManagement

• - 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.

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Diabetic KetoacidosisManagement

• -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).

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Diabetic KetoacidosisMonitoring

• 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.

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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

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Lactic Acidosis

• Lactic acidosis is usually associated with renal
  failure

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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
Variable None present Ketosis
Severe None Moderate/ Severe Acidosis
Variable Prominent Prominent Dehydration
Present None Present Hyperventilation
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Long-term complication

• long-term complications may result from
• Microvascular changes
• Macrovascular disease

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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