Symptoms of Hyperglycemia
Marked hyperglycemia presents with the classic triad of polyuria (frequent urination), polydipsia (excessive thirst), and weight loss, often accompanied by polyphagia (increased appetite), blurred vision, and fatigue. 1
Classic Osmotic Symptoms
The hallmark symptoms of hyperglycemia result from osmotic effects of elevated glucose:
- Polyuria (frequent urination) occurs as excess glucose spills into urine, drawing water with it through osmotic diuresis 1, 2
- Polydipsia (excessive thirst) develops as a compensatory response to fluid loss from polyuria 1, 2
- Weight loss despite normal or increased appetite (polyphagia) results from cellular glucose deprivation and metabolic breakdown 1, 2
Visual and Neurological Manifestations
- Blurred vision results from osmotic changes in the lens of the eye caused by hyperglycemia 1, 2
- Weakness and fatigue are common complaints that overlap with the osmotic symptoms 2
Infectious and Wound Healing Complications
Chronic hyperglycemia impairs immune function and tissue repair:
- Recurring infections, particularly skin, urinary tract, and yeast infections, are manifestations of hyperglycemia 2
- Poor wound healing accompanies chronic hyperglycemia due to increased susceptibility to infections 1, 2
- Impairment of growth and susceptibility to certain infections may accompany chronic hyperglycemia 1
Warning Signs of Life-Threatening 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. 2
Additional severe symptoms include:
- Confusion or altered mental status indicating severe hyperglycemia or DKA 2
- Nausea and vomiting may signal progression to DKA or hyperosmolar hyperglycemic syndrome 1, 3
Important Clinical Caveats
- Symptoms alone are poor predictors of actual blood glucose levels, making regular glucose monitoring essential rather than relying on symptoms 2
- In type 2 diabetes, hyperglycemia sufficient to cause pathologic changes may be present for a long period without clinical symptoms 1
- Blood glucose >19.4 mmol/L (350 mg/dL) requires immediate physician notification 2
- Random blood glucose ≥11.1 mmol/L (200 mg/dL) on multiple occasions warrants medical evaluation 2
Acute Life-Threatening Consequences
Uncontrolled diabetes can progress to two severe complications:
- Hyperglycemia with ketoacidosis (DKA) characterized by nausea, vomiting, and high ketone levels 1, 3
- Nonketotic hyperosmolar syndrome presenting with extreme dehydration and neurologic symptoms 1, 4, 5
Both conditions require immediate medical intervention with fluid resuscitation, insulin therapy, and electrolyte monitoring 3, 4.