What are the symptoms of hyperglycemia?

Symptoms of Hyperglycemia

The most common symptoms of hyperglycemia include polydipsia (excessive thirst), polyuria (frequent urination), blurred vision, fatigue, and unexplained weight loss, which may be accompanied by polyphagia (increased hunger). 1

Classic Symptoms

• Polyuria - Increased urination frequency and volume due to glucose spillage into urine
• Polydipsia - Excessive thirst resulting from fluid loss through increased urination
• Weight loss - Despite possible increased appetite (polyphagia)
• Blurred vision - Due to lens swelling caused by osmotic effects of chronic hyperglycemia 2
• Fatigue - Resulting from cellular inability to utilize glucose properly

Additional Symptoms

• Recurrent infections 2
• Dry skin
• Poor wound healing
• Nausea and vomiting (in severe cases)
• Abdominal pain (in severe cases)
• Fruity-smelling breath (indicating ketosis) 1

Progression to Serious Complications

If hyperglycemia remains untreated, it can progress to more serious conditions:

Diabetic Ketoacidosis (DKA)

• More common in type 1 diabetes
• Characterized by nausea, vomiting, abdominal pain
• High levels of ketones in blood and urine
• Fruity-smelling breath
• Can develop rapidly, especially if insulin supply is interrupted in pump users 1

Hyperosmolar Hyperglycemic State (HHS)

• More common in older adults with type 2 diabetes
• Marked by profound dehydration
• Neurological symptoms ranging from lethargy to coma
• Blood glucose typically >600 mg/dL
• Serum osmolarity >320 mOsm/L 3, 4

Age-Related Differences in Presentation

Children and Adolescents

• May present with the classic symptoms
• Can also show lethargy, behavioral changes, and poor school performance 1
• Often diagnosed with type 2 diabetes when already in hyperosmolar hyperglycemic state 4

Elderly Patients

• May not experience typical symptoms of polyuria and polydipsia
• Often present with weight loss and fatigue that might be mistakenly attributed to aging 1
• Higher risk for hyperosmolar hyperglycemic state 3

Diagnostic Criteria

According to the American Diabetes Association, hyperglycemia sufficient for diabetes diagnosis is defined as:

• Fasting plasma glucose ≥126 mg/dL (7.0 mmol/L) after at least 8 hours of fasting, OR
• Symptoms of hyperglycemia and casual plasma glucose ≥200 mg/dL (11.1 mmol/L), OR
• 2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during an oral glucose tolerance test 2

Clinical Implications

Hyperglycemia increases the risk of both microvascular and macrovascular complications, even with brief periods of elevated blood glucose 5. It can also impair host defenses, decreasing polymorphonuclear leukocyte mobilization, chemotaxis, and phagocytic activity, which increases infection risk 6.

Warning Signs Requiring Immediate Medical Attention

• Marked hyperglycemia with symptoms of nausea and vomiting
• Signs of dehydration (extreme thirst, dry mouth, sunken eyes)
• Altered mental status or confusion
• Fruity breath odor
• Rapid, deep breathing (Kussmaul respiration)
• Abdominal pain

Early recognition and treatment of hyperglycemia are essential to prevent progression to life-threatening conditions like DKA or HHS, which carry significant mortality rates of 10-20% 3, 4.