High blood sugar, or hyperglycemia, occurs when there is too much glucose in the bloodstream. Glucose, a type of sugar, serves as the body’s primary source of energy, derived from the carbohydrates in food and drinks. Insulin, a hormone produced by the pancreas, enables glucose to move from the blood into the body’s cells for energy or storage.
Hyperglycemia happens when the body either doesn’t produce enough insulin or can’t effectively use it (insulin resistance), causing glucose to build up in the blood instead of entering cells. While occasional mild elevations may not pose an immediate threat, persistently high levels can damage nerves, blood vessels, tissues, and organs throughout the body. Understanding hyperglycemia is crucial, especially for individuals with diabetes who frequently experience such episodes.
Immediate Signs and Symptoms
Elevated blood sugar often causes noticeable signs. Increased thirst (polydipsia), often accompanied by a dry mouth, is common. This thirst arises as the kidneys work to filter and excrete excess glucose from the blood. Frequent urination (polyuria) often accompanies increased thirst. The kidneys remove surplus glucose by flushing it out through urine, which draws more water from the body, leading to dehydration and heightened thirst.
Despite abundant glucose in the bloodstream, cells may not be receiving enough energy, leading to fatigue and weakness. Blurred vision can also occur as high glucose levels affect the lens of the eye, causing it to swell and change shape. Headaches and difficulty concentrating are additional symptoms some individuals experience, reflecting the body’s struggle to function optimally with imbalanced glucose levels.
Increased hunger (polyphagia) can also manifest, even after eating. The body perceives a lack of energy in its cells, prompting a continuous desire for food despite the high glucose levels in the blood.
How the Body Reacts to High Glucose
When blood glucose levels remain high, the body responds. Cells throughout the body, particularly those in muscles and fat tissue, struggle to absorb glucose, even when there is an abundance of it in the blood. This happens because insulin is insufficient or cells are less responsive to its signals.
In cases of insulin resistance, the pancreas may initially attempt to compensate by producing more insulin to overcome the cells’ impaired sensitivity. However, over time, if the resistance persists, the pancreas can become overworked and its beta cells, which produce insulin, may wear out, further exacerbating the problem of insufficient insulin.
The excess glucose circulating in the bloodstream begins to interact with proteins and fats, forming harmful compounds that can damage blood vessels and nerves over time.
Long-Term Health Consequences
Unmanaged, persistently high blood sugar leads to severe chronic health problems affecting multiple organ systems. Cardiovascular disease is a concern, as elevated glucose levels contribute to the narrowing and hardening of blood vessels (atherosclerosis), increasing the risk of heart attacks and strokes. Damage to blood vessels can also result in high blood pressure.
Kidney damage (diabetic nephropathy) is a consequence. The tiny blood vessels within the kidneys, responsible for filtering waste, become compromised by high blood sugar, impairing their function and potentially leading to kidney failure, sometimes requiring dialysis or a transplant. This ongoing strain on the kidneys can significantly diminish their ability to maintain the body’s fluid and electrolyte balance.
Nerve damage (neuropathy) develops in individuals with prolonged hyperglycemia. High blood sugar can harm the blood vessels that supply oxygen to nerves, interfering with their ability to transmit signals. This damage commonly affects the extremities, causing numbness, tingling, or pain, but it can also impact nerves controlling internal organs, leading to digestive issues or other dysfunctions.
Eye damage, specifically diabetic retinopathy, occurs when high glucose levels harm delicate blood vessels in the retina, causing them to leak fluid or bleed, which distorts vision.
The immune system can be weakened by high blood sugar, making individuals more susceptible to various infections, including skin, urinary tract, and more severe systemic infections. Poor blood flow due to vascular damage further hinders the body’s ability to fight off these infections and heal wounds.
When to Seek Medical Help
Knowing when to seek medical help for high blood sugar is important for preventing complications. If blood sugar levels are consistently above 240 mg/dL, or reach 400 mg/dL or higher, medical attention is advised.
Immediate medical attention is necessary if high blood sugar is accompanied by symptoms of diabetic ketoacidosis (DKA), a life-threatening complication. Signs of DKA include nausea, vomiting, abdominal pain, deep and rapid breathing (Kussmaul breathing), a fruity odor on the breath, and confusion. The presence of ketones in the urine, detectable with at-home test kits, along with high blood sugar, also warrants urgent medical care.
For less severe but persistent high blood sugar symptoms like increased thirst, frequent urination, fatigue, or blurred vision that do not improve, consulting a doctor is recommended. Regular check-ups and consistent monitoring are important for managing diabetes and adjusting treatment plans.