Symptoms of Hypoglycemia
Hypoglycemia presents with a characteristic set of symptoms that can be categorized as adrenergic (autonomic) and neuroglycopenic, with symptoms beginning at blood glucose levels below 70 mg/dL and becoming more severe as glucose levels drop further. 1
Classification of Hypoglycemia
Hypoglycemia is classified into three distinct levels according to the American Diabetes Association:
- Level 1: Blood glucose <70 mg/dL (3.9 mmol/L) but ≥54 mg/dL (3.0 mmol/L)
- Level 2: Blood glucose <54 mg/dL (3.0 mmol/L)
- Level 3: A severe event characterized by altered mental and/or physical status requiring assistance for treatment 1, 2
Common Symptoms
Adrenergic (Early Warning) Symptoms
These symptoms result from the release of catecholamines as part of the body's counterregulatory response:
Neuroglycopenic Symptoms
These symptoms result from insufficient glucose supply to the brain:
- Confusion/disorientation
- Weakness/fatigue
- Dizziness
- Blurred vision
- Difficulty concentrating
- Slurred speech
- Headache
- Irritability 1, 3, 4
Severe Hypoglycemia Symptoms
If hypoglycemia progresses to Level 3 (severe), symptoms may include:
Symptom Frequency
In clinical studies, the most frequently reported symptoms of severe hypoglycemia were:
- Weakness/fatigue (approximately 30%)
- Sweating (approximately 27%)
- Confusion/disorientation (22-29%)
- Shakiness (approximately 20%) 5
Special Considerations
Hypoglycemia Unawareness
Many people with diabetes, especially those with recurrent hypoglycemia, may develop impaired awareness of hypoglycemia, where the early warning symptoms fail to occur or are not recognized. This condition significantly increases the risk of severe hypoglycemia 1.
Atypical Presentations
Hypoglycemia can sometimes present with atypical symptoms that may mimic other conditions:
- Stroke-like symptoms including focal neurological deficits
- Behavioral changes
- Cerebellar signs (ataxia, dysarthria)
- Psychosis-like symptoms 6
High-Risk Groups
Certain populations are at higher risk for hypoglycemia and should be monitored more carefully:
- Elderly patients
- Those with cognitive impairment
- Patients with long-duration diabetes
- Those with renal dysfunction
- Patients on insulin or sulfonylureas
- Those with a history of severe hypoglycemia 1, 2
Clinical Implications
Recognition of hypoglycemia symptoms is critical for prompt treatment and prevention of progression to severe hypoglycemia. Patients and caregivers should be educated about these symptoms and appropriate management strategies, including:
- Immediate treatment with 15-20g of glucose for conscious patients
- Having glucagon available for severe episodes
- Adjusting diabetes management plans after hypoglycemic events 1
Hypoglycemia symptoms can vary between individuals and may change over time, particularly in those with longstanding diabetes. Regular assessment of symptom awareness should be part of routine diabetes care.