Can delirium occur after a hypoglycemic (low blood sugar) event?

Delirium Following Hypoglycemic Events

Yes, delirium can occur during or after a hypoglycemic event, particularly in cases of severe hypoglycemia (level 3) which is characterized by altered mental and/or physical functioning requiring assistance from another person for recovery. 1

Relationship Between Hypoglycemia and Delirium

• Hypoglycemia, especially when severe, can cause neuroglycopenic symptoms including confusion, which is a key feature of delirium 1
• Level 2 hypoglycemia (blood glucose <54 mg/dL [3.0 mmol/L]) is the threshold at which neuroglycopenic symptoms begin to occur 1
• Level 3 hypoglycemia can progress to altered mental status, loss of consciousness, seizure, coma, or death 1
• In critically ill patients with diabetes, relative hypoglycemia (blood glucose >30% below estimated average) is associated with a significantly higher incidence of ICU delirium 2

Risk Factors for Hypoglycemia-Related Delirium

• Advanced age increases vulnerability to both hypoglycemia and delirium 1
• Pre-existing cognitive impairment increases risk of both hypoglycemia and subsequent delirium 1, 3
• African Americans are at substantially increased risk of level 3 hypoglycemia 1
• Insulin use, poor glycemic control, albuminuria, and poor cognitive function are additional risk factors 1
• Critically ill patients are particularly vulnerable to both hypoglycemia and delirium 2, 4

Clinical Presentation and Recognition

• Symptoms of hypoglycemia include shakiness, irritability, confusion, tachycardia, and hunger 1, 5
• Delirium is characterized by an acute change in cognition and attention, with symptoms that may fluctuate throughout the day 3
• Hypoglycemia unawareness (absence of warning symptoms) increases risk of severe hypoglycemic episodes and subsequent delirium 1
• The combination of hyperglycemia and hypoglycemia occurring on the same day is strongly associated with transition to delirium in non-diabetic ICU patients 4

Management of Hypoglycemia to Prevent Delirium

• Treat hypoglycemia immediately with fast-acting carbohydrates when blood glucose is ≤70 mg/dL (3.9 mmol/L) 1, 5
• Pure glucose is the preferred treatment, but any form of carbohydrate containing glucose will raise blood glucose 1
• For severe hypoglycemia with altered mental status, glucagon administration is indicated 1, 5
• After initial treatment and glucose normalization, patients should consume a meal or snack to prevent recurrent hypoglycemia 1
• In critically ill patients, close monitoring of glucose levels during delirium is essential, especially in diabetic patients, to prevent hypoglycemia 6

Recovery and Long-Term Effects

• Most cognitive functions typically recover within 1.5 days after a severe hypoglycemic episode 7
• However, recurrent episodes of severe hypoglycemia may be associated with persistent cognitive decrements and altered mood states 7
• A history of severe hypoglycemia in older adults with type 2 diabetes has been associated with greater risk of dementia 1
• Cognitive impairment at baseline or decline in cognitive function is significantly associated with subsequent episodes of severe hypoglycemia 1

Prevention Strategies

• Individualize glycemic targets based on hypoglycemia risk 1
• For patients with hypoglycemia unawareness or recent severe hypoglycemia, temporarily raise glycemic targets to avoid further episodes 1
• Implement ongoing assessment of cognitive function with increased vigilance for hypoglycemia in patients with impaired or declining cognition 1
• Educate patients about recognizing and treating symptoms of hypoglycemia 5
• In hospitalized patients at risk for delirium, implement interventions including repeated reorientation, promotion of good sleep hygiene, early mobilization, and correction of dehydration 3