What are the signs and symptoms of hyperglycemia that patients should be educated about?

Signs and Symptoms of Hyperglycemia for Patient Education

Patients should be educated that marked hyperglycemia causes frequent urination (polyuria), excessive thirst (polydipsia), blurred vision, fatigue, and recurring infections, with these symptoms requiring immediate medical attention when present. 1

Classic Osmotic Symptoms

The most specific symptoms of hyperglycemia result from osmotic effects of elevated blood glucose:

• Polyuria (frequent urination) - occurs as excess glucose spills into urine, drawing water with it 1, 2
• Polydipsia (excessive thirst) - develops as a compensatory response to fluid loss 1, 2
• Dry mouth - accompanies dehydration from osmotic diuresis 2
• Increased need to urinate - particularly noticeable at night 2

These osmotic symptoms typically appear when blood glucose exceeds 15 mmol/L (270 mg/dL), though individual thresholds vary 2

Visual and Neurological Symptoms

Hyperglycemia affects multiple organ systems beyond fluid balance:

• Blurred vision - results from osmotic changes in the lens of the eye 1, 2
• Dizziness and light-headedness - may indicate more severe hyperglycemia 2
• Weakness and fatigue - common complaints that overlap with osmotic symptoms 1, 2

Metabolic and Systemic Signs

Additional manifestations that patients should recognize:

• Unintentional weight loss - despite normal or increased appetite (polyphagia) 1
• Recurring infections - particularly skin, urinary tract, and yeast infections 1
• Poor wound healing - increased susceptibility to infections accompanies chronic hyperglycemia 1
• Sweet or funny taste in mouth - reported by some patients 2

Behavioral and Cognitive Changes

Hyperglycemia can affect mental status:

• Irritability and feeling tense - part of the "agitation" symptom cluster 2
• Restlessness and poor concentration - interfere with daily activities 2
• Not feeling right - a non-specific but important warning sign 2

Warning Signs of Severe Hyperglycemia

Patients must seek immediate medical care if they experience nausea, vomiting, or abdominal pain with hyperglycemia, as these may indicate diabetic ketoacidosis (DKA), a life-threatening emergency. 1, 3

Additional red flags requiring urgent evaluation:

• Headache with nausea - suggests metabolic decompensation 2
• Confusion or altered mental status - indicates severe hyperglycemia or DKA 1
• Rapid breathing or shortness of breath - may signal ketoacidosis 3

Blood Glucose Thresholds for Action

Educate patients on specific glucose values requiring intervention:

• Random blood glucose ≥11.1 mmol/L (200 mg/dL) on multiple occasions warrants medical evaluation 1
• Blood glucose >19.4 mmol/L (350 mg/dL) requires immediate physician notification 1
• Persistent elevation despite usual treatment necessitates adjustment of diabetes regimen 1

Special Populations and Contexts

Patients on Corticosteroids

• Expect peak hyperglycemia 7-9 hours after steroid dose, with afternoon and evening glucose elevations most prominent 1, 4
• Monitor more frequently during steroid therapy, as hyperglycemia severity correlates with steroid dose 1, 4

Patients on SGLT2 Inhibitors

• Stop medication immediately and seek emergency care if experiencing nausea, vomiting, or abdominal pain, as these drugs increase risk of euglycemic DKA 3
• Patients should have capability to measure ketones at home 1

Key Educational Points

Emphasize that symptoms alone are poor predictors of actual blood glucose levels, making regular glucose monitoring essential rather than relying on symptoms. 3

Common pitfalls to address:

• Younger patients experience more intense symptoms at any given glucose level compared to older adults 2
• Fasting blood glucose may not capture severity - postprandial (after-meal) testing is often more revealing 1
• Symptoms may be absent despite significant hyperglycemia, particularly in those with long-standing diabetes 3

Patients should understand that acute hyperglycemia directly impairs multiple body functions, and prompt treatment prevents both immediate complications and long-term organ damage affecting eyes, kidneys, nerves, heart, and blood vessels 1, 3