Diabetes is a chronic condition that affects how the body converts food into energy, leading to high blood sugar, or glucose, levels. In Type 1 diabetes, the immune system mistakenly attacks the insulin-producing cells in the pancreas, resulting in an absolute lack of the hormone insulin. Type 2 diabetes, which accounts for the vast majority of cases, involves the body not using insulin effectively, a state known as insulin resistance, or not producing enough of it. The condition can remain completely hidden for years, especially Type 2, with millions of adults in the United States currently unaware they have it. This lack of early detection allows high blood sugar to cause silent, progressive damage throughout the body.
Factors Contributing to Missed Diagnosis
The insidious nature of Type 2 diabetes is the primary reason it often goes undiagnosed until complications arise. Symptoms develop so slowly that people frequently dismiss them as normal signs of aging or minor, temporary ailments. This gradual onset allows the body time to partially adjust to rising glucose levels, making the symptoms less acute or noticeable.
The precursor to Type 2 diabetes, known as prediabetes, is often entirely asymptomatic, yet involves blood sugar levels that are higher than normal. For Type 1 diabetes, the onset is typically rapid, but it can be misdiagnosed because initial symptoms—like nausea, vomiting, and fatigue—are often mistaken for a common flu or viral infection. Without regular screening, many asymptomatic people who are at risk will never have their blood sugar tested.
Atypical Physical Manifestations
Beyond the classic signs, such as increased thirst and frequent urination, undiagnosed diabetes can manifest through physical signs not immediately connected to blood sugar. Recurrent or persistent skin infections, including yeast and fungal infections, can be a subtle sign. High glucose levels in the blood and urine create an environment where yeast and bacteria thrive, while simultaneously impairing the immune system’s ability to fight infection.
Wounds or sores that take a long time to heal may also indicate elevated blood sugar. High glucose damages small blood vessels, leading to poor circulation and preventing necessary nutrients and immune cells from reaching the injured site.
Another overlooked sign is the development of dark, velvety patches of skin, typically found in the armpits, neck, or groin. This condition, called acanthosis nigricans, signals insulin resistance.
Unexplained sudden weight loss, especially in Type 1 diabetes, occurs because the body cannot use glucose for energy and begins rapidly breaking down muscle and fat instead. Persistent fatigue is common as cells are starved of the glucose they need for fuel.
Changes in vision, such as temporary blurriness, happen when high glucose levels cause fluid shifts in the eye’s lens, affecting its ability to focus. Tingling, numbness, or a pins-and-needles sensation in the hands or feet, known as peripheral neuropathy, can represent the earliest stages of nerve damage caused by high blood sugar.
Acute Metabolic Emergencies
When diabetes remains undiagnosed, particularly Type 1, the first sign can be an acute metabolic event. Diabetic Ketoacidosis (DKA) occurs when the body, lacking sufficient insulin, breaks down fat for energy, producing acidic compounds called ketones. This leads to metabolic acidosis, where the blood becomes acidic, presenting with symptoms like nausea, vomiting, abdominal pain, and a fruity odor on the breath.
Hyperosmolar Hyperglycemic State (HHS), more common with undiagnosed Type 2 diabetes, involves extremely high blood sugar levels, often exceeding 600 mg/dL, without significant ketone production. The high glucose pulls water from the body, causing severe dehydration and hyperosmolarity. HHS typically develops over days or weeks and can lead to confusion, neurological symptoms, or coma. Both DKA and HHS require immediate medical intervention as they can be fatal if untreated.
Systemic Consequences of Prolonged Hyperglycemia
Prolonged high blood sugar inflicts progressive damage on blood vessels and nerves throughout the body. This damage is systemic, affecting nearly every major organ and leading to long-term, often irreversible complications.
Cardiovascular disease risk is increased because high glucose levels damage the inner lining of blood vessels, contributing to atherosclerosis, or the hardening of arteries. This vascular damage raises the probability of heart attack, stroke, and peripheral artery disease.
Diabetic nephropathy refers to kidney damage that develops over years as the small filtering units are strained and scarred by consistently high glucose. This can eventually lead to chronic kidney disease and kidney failure requiring dialysis or a transplant.
In the eyes, diabetic retinopathy is caused by the deterioration of the tiny blood vessels supplying the retina. This condition can lead to vision impairment and, in advanced stages, permanent blindness.
Nerve damage, or neuropathy, is a common long-term complication resulting from high blood sugar harming nerve fibers. This typically starts in the feet and legs, causing numbness and loss of sensation. Unnoticed foot injuries can progress rapidly to severe infections and ulcers due to poor circulation, sometimes necessitating amputation.
Recommended Screening and Testing
Early detection through routine screening offers the best chance to prevent severe long-term complications. The three primary blood tests used to diagnose diabetes and prediabetes are the A1C test, the Fasting Plasma Glucose (FPG) test, and the Oral Glucose Tolerance Test (OGTT). The A1C test provides an average of blood sugar control over the previous two to three months and does not require fasting.
The FPG test measures blood glucose after an overnight fast, while the OGTT measures blood glucose levels two hours after drinking a sugary solution. Screening is recommended for all adults starting at age 35, and if results are normal, retesting is advised every three years. Testing should begin earlier and be more frequent for individuals with risk factors, such as overweight or obesity, a family history of diabetes, or a history of gestational diabetes.