hyperglycemia

Hyperglycemia is a condition characterized by higher-than-normal blood glucose levels. It is a central feature of diabetes mellitus but can occur in people without diabetes during acute illness, stress, pregnancy, or as a side effect of certain medications. The clinical significance depends on the level and duration of hyperglycemia as well as individual health factors.

Causes of hyperglycemia include impaired insulin action or deficiency, increased hepatic glucose production, and reduced glucose uptake by tissues. In diabetes, insufficient insulin production (type 1) or insulin resistance (type 2) commonly leads to elevated glucose. Non-diabetic causes encompass infections, dehydration, medications such as glucocorticoids or certain antipsychotics, and hormonal disorders; gestational diabetes is another context in which hyperglycemia can occur.

Symptoms may include increased urination (polyuria), excessive thirst (polydipsia), fatigue, blurred vision, and unintentional weight loss. In severe cases, nausea, vomiting, abdominal pain, confusion, or altered consciousness may arise, particularly with diabetic ketoacidosis or hyperosmolar hyperglycemic state.

Diagnosis and monitoring rely on blood glucose testing. Fasting plasma glucose, random plasma glucose, and the oral glucose tolerance test are used criteria in diagnosing diabetes. HbA1c reflects average glucose over several weeks to months but is not used alone to diagnose acute hyperglycemia. Monitoring tools such as home glucose meters and continuous glucose monitoring help guide management.

Management aims to normalize glucose levels and address underlying causes. Treatments range from lifestyle modifications and adjustment of diabetes medications to urgent medical care for emergencies like diabetic ketoacidosis or hyperosmolar hyperglycemic state, which require fluids, electrolyte correction, and insulin therapy. Prolonged hyperglycemia increases the risk of cardiovascular disease, neuropathy, nephropathy, retinopathy, and infections. Prevention centers on maintaining good glycemic control and prompt management during illness or stress.