Acute complications of hypoglycemia and hyperglycemia
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Introduction
Both hypoglycemia and hyperglycemia can lead to acute, potentially life-threatening complications. Rapid recognition and treatment are essential to prevent neurological damage, cardiovascular events, or death.
Hypoglycemia
Hypoglycemia is defined as abnormally low blood glucose levels, usually below 3.0–3.5 mmol/L. It results from an imbalance between insulin levels, food intake, and energy demands.
Causes
- Excess insulin administration
- Missed meals or fasting
- Alcohol
- Exercise
- Critical illness (e.g., sepsis, liver failure)
Symptoms
Autonomic symptoms-
- Sweating, tremor
- Palpitations
- Anxiety
- Hunger
Neuroglycopenic symptoms-
- Weakness, confusion
- Visual disturbances
- Seizures
- Loss of consciousness or coma
Acute Complications
- Hypoglycemic coma
- Seizures
- Irreversible brain injury if prolonged
- Arrhythmias due to sympathetic activation
Management
- Conscious patient: oral glucose (15–20 g), repeat if necessary
- Unconscious patient: IV glucose or IM glucagon
Hyperglycemia
Severe acute hyperglycemia can lead to:
- Diabetic ketoacidosis (DKA)
- Hyperosmolar hyperglycemic state (HHS)
Both require urgent hospital treatment.
Diabetic Ketoacidosis (DKA):
Definition
A life-threatening condition with hyperglycemia, metabolic acidosis, and ketone production.
Causes
- Missed insulin
- Infection
- Acute illness
- New-onset type 1 diabetes
Symptoms
- Polyuria, polydipsia
- Nausea, vomiting
- Abdominal pain
- Dehydration
- Kussmaul breathing
- Altered consciousness
Acute Complications
- Severe dehydration and shock
- Electrolyte disturbances (especially hypokalemia)
- Cerebral edema (mainly in children)
- Coma or death
Hyperosmolar Hyperglycemic State (HHS):
Definition
Extremely high glucose and serum osmolality with severe dehydration and minimal or no ketosis.
Symptoms
- Intense thirst
- Profound dehydration
- Weakness
- Neurological signs (confusion, seizures, coma)
Acute Complications
- Shock
- Thrombotic events
- Seizures
- High mortality
Comparison of DKA and HHS
DKA develops rapidly (hours) and features ketosis and metabolic acidosis due to absolute insulin deficiency, most often in type 1 diabetes. Hyperglycemia is moderate to severe, and dehydration is present but not extreme.
HHS develops more slowly (days) in older patients with type 2 diabetes. Insulin levels are usually sufficient to prevent ketosis, so acidosis is absent or mild. However, hyperglycemia is extreme, leading to severe dehydration and high serum osmolality. Mortality is higher due to the degree of dehydration and associated complications.
Management of Acute Hyperglycemic Crises
- Intravenous fluids
- Insulin therapy
- Potassium replacement
- Treatment of underlying cause (infection, MI, etc.)
- Monitoring of glucose, electrolytes, and acid-base balance
Conclusion
Hypoglycemia can rapidly lead to seizures, coma, and brain injury, while severe hyperglycemia may progress to DKA or HHS, both of which cause dehydration, metabolic imbalance, and potentially death. Early identification and timely therapy are crucial to prevent serious complications.
References
- Guyton & Hall. Textbook of Medical Physiology.
- American Diabetes Association. Diabetes Care Guidelines.
- Kitabchi AE et al. Hyperglycemic crises in adult patients. Diabetes Care.
