Hyperglycemia

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton, Alexandra Stead, Vidya Acharya, Kim Jackson and Mohamed A Hassanin  

Introduction

Hyperglycaemia means high blood sugar level (specifically of the sugar glucose in the blood). This can develop over many hours or days. While it’s often discussed in connection with diabetes, it’s important to understand that hyperglycaemia can be both a symptom and a condition in itself, depending on the context. Many people do not experience the symptoms of hyperglycaemia until their blood sugar levels are extremely high.

Hyperglycaemia is blood glucose greater than 125 mg/dL while fasting and greater than 180 mg/dL (10/mmol/L) 2 hours postprandial. A patient has impaired glucose tolerance, or pre-diabetes, with a fasting plasma glucose of 100 mg/dL to 125 mg/dL (5.6-6.9 mmol/L). A patient is termed diabetic with a fasting blood glucose of greater than 125 mg/dL (6.9 mmol/L).

When hyperglycaemia is left untreated, it can lead to many serious life-threatening complications that include damage to the eye, kidneys, nerves, heart, and peripheral vascular system. Thus, it is vital to manage hyperglycaemia effectively and efficiently to prevent complications of the disease and improve patient outcomes.

The signs of hyperglycaemia are polydipsia (a great thirst), polyuria (a need to urinate often), and a dry mouth.

Aetiology

Factors contributing to hyperglycaemia include reduced insulin secretion, decreased glucose utilization, and increased glucose production.

• Glucose homeostasis is a balance between hepatic glucose production and peripheral glucose uptake and utilization.
• Insulin is the most important regulator of glucose homeostasis.

Secondary Cause of hyperglycaemia

• Destruction of the pancreas from chronic pancreatitis, hemochromatosis, pancreatic cancer, and cystic fibrosis
• Endocrine disorders that cause peripheral insulin resistance like Cushing syndrome, acromegaly, and pheochromocytoma
• Use of medications like glucocorticoids, phenytoin, and estrogens
• Gestational diabetes is known to occur in 4% of all pregnancies and is primarily due to decreased insulin sensitivity
• Total parental nutrition and dextrose infusion
• Reactive as seen postoperatively or in critically ill patients

How Hyperglycaemia Leads to Diabetes

Diabetes develops when the body can no longer properly regulate blood sugar levels. Persistent or repeated episodes of hyperglycaemia may signal the early stages of this breakdown:

• Type 1 diabetes: The immune system destroys the insulin-producing cells in the pancreas. Without insulin, glucose can’t enter cells, and blood sugar rises — leading to sustained hyperglycaemia.
• Diabetes Mellitus Type 2 : The body becomes resistant to insulin, or the pancreas can’t produce enough to keep blood glucose in balance. Initially, hyperglycaemia may be mild and intermittent, but over time, it becomes chronic, resulting in diabetes.
• Prediabetes: A stage where hyperglycaemia occurs more frequently than normal but not yet high enough to be classified as diabetes. Without intervention, this often progresses to full diabetes.

Risk Factors for hyperglycaemia

• Weight more than 120% of the desired body weight
• Age and Family history of type 2 diabetes
• Poor blood sugar management (e.g. skipping medication doses, eating large amounts of carbohydrates)
• Taking medications such as corticosteroids, diuretics and beta-blockers can increase blood glucose
• Presence of hyperlipidemia or hypertension
• History of gestational diabetes or insulin problems
• Illness, stress and hormonal changes (stress can trigger release of hormones like cortisol and adrenaline, which raise blood glucose).
• Lifestyle (sedentary lifestyle, unhealthy diet, obesity, smoking and excessive alcohol use)
• Presence of polycystic ovarian syndrome

Signs and Symptoms of Hyperglycaemia

Early symptoms occur because the body is trying to remove excess sugar through urine and because cells aren’t getting enough glucose for energy.

Early Signs and Symptoms include:

• Increased thirst (polydipsia)
• Frequent urination (polyuria)
• Increased hunger (polyphagia)
• Fatigue or lack of energy
• Blurred vision
• Headaches
• Difficulty concentrating

Moderate to Severe Symptoms include:

• Dry mouth and dry skin
• Unexplained weight loss (especially in type 1 diabetes)
• Recurrent infections (such as urinary tract, skin, or yeast infections)
• Slow wound healing
• Tingling or numbness in hands and feet

Very high or prolonged hyperglycaemia can lead to serious complications such as diabetic ketoacidosis (DKA) or hyperosmolar hyperglycaemic state (HHS).

Severe or Emergency Symptoms include:

• Nausea and vomiting
• Abdominal pain
• Rapid, deep breathing
• Fruity-smelling breath
• Confusion, drowsiness, or loss of consciousness

Epidemiology

The incidence of hyperglycaemia has increased dramatically over the last two decades due to increased obesity, decreased activity level, and an aging population. The prevalence is equal between men and women. There are approximately 589 million adults aged between 20-79 years living with diabetes in 2024, which is expected to increase to 853 million by 2050. The countries with the greatest number of patients with diabetes included China, India, United States, Brazil, and Russia. hyperglycaemia is more prominent in low to medium-income households. In 2021, almost half of all people with diabetes (44.7%; 239.7 million) were unaware of their condition. The prevalence of undiagnosed diabetes is highest in Africa (53.6%), Western Pacific (52.8%), and Southeast Asia (51.3%), compared to 24.2% in North America and the Caribbean.

Management

The treatment goals of hyperglycaemia involve eliminating the symptoms related to hyperglycaemia and reducing long-term complications. Glycaemic control in patients with type 1 diabetes is achieved by a variable insulin regimen along with proper nutrition. Patients with type 2 diabetes are managed with diet and lifestyle changes as well as medications. Type 2 diabetes also may be managed on oral glucose-lowering agents. Patients with hyperglycaemia need to be screened for complications including retinopathy, nephropathy, and cardiovascular disease. For full elaboration see links to Diabetes as shown above.

Advances in technology have made managing diabetes more precise and convenient. Two key tools — Continuous Glucose Monitors (CGMs) and Insulin Pumps — help people maintain better blood sugar control and improve quality of life. CGM is a small device inserted under the skin that tracks blood glucose levels in real time, day and night. It can alert users for hyperglycaemia or hypoglycaemia before any symptoms appear. An Insulin Pump is a small, programmable device connected to the body through a thin tube and cannula (or patch), that delivers a continuous basal dose of insulin throughout the day. It can provide flexibility in meal timing and physical activity, as well as reduces blood sugar fluctuations. There are some limitations to individuals with diabetes using insulin pump technologies, which include risk of infusion set failure, pump malfunction, skin irritation, and alarm fatigue.

Physiotherapy

The adoption and maintenance of exercise and physical activity are critical foci for blood glucose management and overall health in individuals with diabetes and prediabetes. It is advised that people with type 2 diabetes should adopt frequent activity breaks, through reducing periods of sitting and sedentary time, and engage in physical activity regularly. See Physical Activity in Diabetes for further details. For those with prediabetes, high intensity interval training (HITT) and aerobic exercise has been found to to reduce fasting glucose levels and control glucose levels. Healthcare professionals need to be mindful that exercise prescription is tailored to each individual, tasking into consideration of numerous factors, including time of exercises in relation to meals, interactions with medications and lifestyle commitments.

Prognosis

The prognosis of individuals with hyperglycaemia depends on how well the levels of blood glucose are controlled. Chronic hyperglycaemia can cause severe life- and limb-threatening complications if not appropriately controlled. Numerous studies have shown that untreated hyperglycaemia shortens lifespan and worsens the quality of life. However, controlling blood sugars too quickly can result in hypoglycaemia which is not well tolerated by elderly individuals who already may have a pre-existing cardiovascular disease.Changes in lifestyle, regular physical exercise, and changes in diet are the keys to a better prognosis.