Diabetes 101: Types, Symptoms, Causes, and Management

Diabetes 101: Types, Symptoms, Causes, and Management

What Is Blood Glucose Reading Diabetes 101: Types, Symptoms, Causes, and Management 14 minutes Next Type 1 Diabetes

Diabetes is a metabolic disease characterized by high blood sugar levels, a troublesome situation triggered by a defect in insulin production or the body's improper use of it, or sometimes, a combo of both.

Insulin is a hormone produced by your pancreas. It's the "traffic cop" for glucose, guiding it into your cells to provide energy. In the case of diabetes, your body either can't produce enough insulin, or can't use it properly. So, when there's not enough insulin or cells stop responding to it, excess blood sugar stays in your bloodstream, and over time, this can cause severe health problems. It's like a sugar traffic jam that, if not managed, can cause a significant health pile-up. 

circulation of blood sugar in the body

Here are the topics that we'll cover in this complete guide to Blood Glucose: 


The most common types of diabetes are Type 1, Type 2, Gestational, and mixed diabetes. In addition, there are combined types, unclassified types, and other specific types. It's safe to say that diabetes is more diverse than previously thought, with potential combinations of forms playing out like a complex game of health chess.

Type 1
Type 1 Diabetes, affecting 5%-10% of diabetic patients, usually emerges in children and young adults, but can develop at any age. This is an autoimmune disease where the body produces minimal or no insulin. Patients rely on daily insulin injections to sustain life, like a fish needs water.

Type 2
Type 2 Diabetes, the most prevalent form, encompasses around 90% of diabetes cases. It's primarily due to the body's inability to produce sufficient insulin, or the body's cells failing to respond properly to insulin, known as insulin resistance. Risk factors include being overweight, lack of exercise, and genetic predisposition. This type typically affects adults, but it's not exclusive to them and can develop at any age. Symptoms may be as subtle as a ninja, hence, this sneak thief often goes undetected until complications emerge years down the line.

Pre-diabetes is the proverbial "calm before the storm" phase preceding Type 2 diabetes. It manifests when blood sugar levels are higher than normal but not high enough for a formal Type 2 diabetes diagnosis. As per statistics, more than a third of U.S. adults (around 96 million) are in this stage, with over 80% of them unaware of their condition. Prediabetes increases the risk of developing Type 2 diabetes, heart disease, and stroke. However, it's usually preventable, and the best way to detect diabetes early is through regular testing and blood checks.

Gestational diabetes
Gestational diabetes is akin to an uninvited guest during pregnancy, typically disappearing post-birth like a temporary visitor. Yet, it can stir up complications during the gestation period, potentially foreshadowing future health concerns for both mother and child. 

Insulin, pancreas, regulation of blood glucose
Glucose Uptake Insulin allows cells to absorb glucose, using it as a fuel source.
Glycogen Synthesis It promotes the storage of excess glucose as glycogen in the liver and muscles.
Fat Storage Insulin aids in the storage of excess energy in fat cells.
Protein Synthesis It also plays a crucial role in protein synthesis, important for cell growth and repair.


Diabetes often reveals itself through the 'three polys and one loss' - polydipsia (a fancy term for being as thirsty as a camel in a desert), polyuria (frequent pit stops at the loo), polyphagia (feeling like a bottomless pit of hunger), and unexplained weight loss that might leave you thinking your scale's broken. Here are some specific manifestations:

  • Frequent nocturia (urination during the night)
  • Persistent thirst
  • Unintentional weight loss
  • Constant hunger
  • Fatigue
  • Blurred vision
  • Numbness or tingling in the hands or feet
  • Dry skin
  • Wounds that heal slowly
  • Increased susceptibility to infections

Early Warnings

Diabetes doesn't play a fanfare before it arrives. Early signs are often non-existent, which means that diabetes is frequently detected during routine check-ups or blood glucose tests. When symptoms like 'three polys and one loss' start to emerge, the disease has usually already taken root and is fairly serious.

Early Symptoms

When we talk about early diabetes, we're referring to prediabetes - a stage usually devoid of prominent discomfort. Detection primarily hinges on blood glucose testing.

Type 1 Diabetes

Patients might experience nausea, vomiting, or stomach pain. Symptoms can appear within a few short weeks or months and might be quite severe. Though Type 1 diabetes is commonly seen starting in children, teenagers, or young adults, it can occur at any age.

Type 2 Diabetes

You may not have any symptoms at all, or you might overlook them due to their gradual development. A routine blood test might reveal high blood sugar levels even before you become aware of the symptoms. Another possible sign of prediabetes could be darkening skin (acanthosis nigricans) in certain areas of your body.

Gestational Diabetes
You may not notice any symptoms of gestational diabetes. Gestational diabetes testing usually occurs between the 24th and 28th weeks of pregnancy, essentially the pregnancy halftime show.

Remember, the severity of diabetes symptoms can depend on how high your sugar levels soar. Some folks, especially those with prediabetes, gestational diabetes, or type 2 diabetes, might not display symptoms, the true masters of hide and seek. In type 1 diabetes, symptoms tend to arrive quickly and can be as dramatic as a soap opera.

comparison of common blood sugar testing methods


Regardless of the type, an excess of glucose circulating in the blood leads to diabetes. However, the causes of elevated blood glucose levels vary depending on the type of diabetes. Usual causes of diabetes include: 

  • Insulin resistance

    The main cause of Type 2 diabetes. A variety of factors and conditions can cause varying degrees of insulin resistance, including obesity (too many donuts?), lack of physical activity (couch potatoes, I'm looking at you), diet, hormonal imbalances, some inherited genes that didn't get the memo, and certain medications.

  • Autoimmune disease

    Type 1 diabetes and LADA occur when your immune system attacks the insulin-producing cells in your pancreas.

Type 1

With Type 1 diabetes, your body doesn't produce insulin - like a factory on permanent strike. If a relative of yours has Type 1 diabetes, your risk of having it is higher.

Type 2

In individuals with Type 2 diabetes, the pancreas cannot produce enough insulin, or the body cells cannot correctly use insulin (referred to as insulin resistance).
Certain risk factors for Type 2 diabetes include:

  • Overweight
    Obesity is the most critical single risk factor for Type 2 diabetes. The more overweight you are, the greater your body's resistance to insulin.

  • Age
    The risk of Type 2 diabetes increases with age, especially after 45 years. Unfortunately, the fountain of youth remains a myth, but you can work on other risk factors to reduce your risk.

  • Family history
    Knowing your family history of diabetes is crucial for diagnosis. If a family member has diabetes, your risk of having it is higher.

  • Pregnancy
    Gestational diabetes occurs during pregnancy and disappears after childbirth. However, about half of women with gestational diabetes are diagnosed with Type 2 diabetes within 15 years. Even without gestational diabetes, women who give birth to babies weighing 9 pounds or more are more likely to develop Type 2 diabetes later in life.

  • Smoking and excessive alcohol
    The consumption is like those rebellious friends who might feel fun to hang out with, but they often bring trouble - they may increase your risk of Type 2 diabetes.

The risk of Type 2 diabetes increases with the number of risk factors you have. If you have two or more risk factors, it's crucial to test your blood glucose levels timely, even if you're feeling wonderful.


Extreme or long-term high blood sugar levels can lead to acute (sudden and severe) and chronic complications due to the impact on various body systems and organs.

Acute Complications

  1. Diabetic Ketoacidosis (DKA)

    Primarily affecting individuals with type 1 diabetes, DKA occurs when the body lacks sufficient insulin to utilize glucose for energy and consequently breaks down fat. This process eventually releases ketones, turning the blood acidic and leading to labored breathing, vomiting, and loss of consciousness. DKA is a five-alarm fire, demanding immediate medical intervention.

  2. Hyperosmolar Hyperglycemic State (HHS)

    The nemesis of those with type 2 diabetes. HHS arises when blood sugar levels are extremely high (over 600 mg/dL) for an extended period, resulting in severe dehydration and mental confusion. HHS necessitates immediate medical treatment.

  3. Severe Hypoglycemia

    Hypoglycemia is like a sugar crash that went overboard—it happens when blood sugar levels dip lower than a limbo stick in the healthy range. Severe hypoglycemia, which indicates very low blood sugar levels, primarily affects diabetes patients who use insulin. Symptoms can include blurred or double vision, clumsiness, disorientation, and seizures. Treatment usually involves emergency glucagon and/or medical intervention.

Chronic Complications

Prolonged high blood sugar levels can cause damage to the blood vessels and nerves that support body tissues, leading to chronic complications. These include:

  1. Cardiovascular diseases: The most common chronic hanger-on in the world of diabetes.
  2. Neuropathy: Nerve damage may lead to numbness, tingling, and/or pain.
  3. Nephropathy: Kidney disease can result in kidney failure, necessitating dialysis or transplantation.
  4. Retinopathy: This eye disease can result in blindness due to damage to the blood vessels in the retina.
  5. Foot disorders and skin infections: Diabetes can cause various foot conditions, some of which may lead to amputations. Skin conditions, including infections, are also common.
  6. Hearing loss and oral health issues: Diabetes may cause hearing loss and oral health problems like gum (periodontal) disease.
  7. In addition to physical health issues, diabetes also takes a toll on mental health, acting like a gloomy cloud that doesn't shift, making people with diabetes two to three times more likely to experience depression.


Food is more than just a source of enjoyment; it's the fuel that our body runs on. What we eat directly impacts our blood glucose levels, making diet a crucial part of managing blood sugar. Let's peel back the layers and see how what's on your plate can influence what's in your blood.

Who should be screened

The onset of Type 1 diabetes symptoms is typically as abrupt as an alarm clock, often prompting blood glucose level checks. As the symptoms of other types of diabetes and pre-diabetes may creep up more stealthily or may not be conspicuous, the American Diabetes Association (ADA) set up a fortress of screening guidelines. The ADA recommends diabetes screening for the following groups:

  • Anyone with a Body Mass Index (BMI) soaring above 25 (23 for Asian Americans) is on the radar, irrespective of age, if they are accompanied by additional risk factors. These factors encompass hypertension, abnormal cholesterol levels, a sedentary lifestyle, a history of Polycystic Ovary Syndrome or heart disease, or having a diabetes-diagnosed close relative.
  • Individuals over 35 should have their sugar levels debut on a blood sugar screening and are advised to get an inaugural blood glucose screening. Repeat the process every three years.
  • Women who have previously experienced gestational diabetes are advised to go for diabetes screening every three years.
  • Anyone who has been handed a pre-diabetes diagnosis is advised to check annually.
  • Anyone battling HIV is advised to participate in diabetes screening.

Like checking the weather forecast before heading out, you could take the American Diabetes Association Diabetes Risk Test to see if you're at risk of Type 2 diabetes.

Besides, considering the stealthy nature of pre-diabetes, anyone within the risk circle should undertake regular checks, to avoid missing the golden treatment window.


A variety of tests are utilized by physicians to diagnose diabetes and prediabetes. Your doctor may recommend different tests depending on whether you display symptoms or are pregnant.

Fasting Plasma Glucose Test
The Fasting Plasma Glucose (FPG) test is akin to waiting for sunrise - it is typically done in the morning after you've fasted for at least 8 hours to measure your blood glucose level at a single point in time.

A1C Test
Also known as the HbA1C or glycated hemoglobin test, the A1C test provides an average of your blood sugar level over the past two to three months. You are allowed to eat and drink prior to this test. Your doctor will report your A1C test result as a percentage, such as an A1C of 8%. The higher the percentage, the higher your average blood sugar levels.

Random Plasma Glucose Test
"Random" means this test can be administered at any time, regardless of your fasting state.

Oral Glucose Tolerance Test
The Oral Glucose Tolerance Test (OGTT) helps detect type 2 diabetes, prediabetes, and gestational diabetes. However, the OGTT is more expensive than the FPG. 

Before the test, you need to fast for at least 8 hours. A healthcare professional will take a blood sample to measure your glucose level after fasting. Afterwards, you'll consume a high-sugar liquid. Another blood sample is taken 2 hours later to check your blood glucose level. If your blood glucose level is high, you may have diabetes. If you're pregnant, your blood will be drawn every hour for 2 to 3 hours. If your blood glucose levels are high two or more times during the OGTT, you may have gestational diabetes.

Glucose Challenge Test
If you're pregnant, your doctor might test you for gestational diabetes with the Glucose Challenge Test, also known as the glucose screening test. In this test, a healthcare professional will take a sample of your blood 1 hour after you drink a sweet liquid containing glucose. You do not need to fast for this test. If your blood glucose level is too high—135 mg/dL to 140 mg/dL or higher—you may need to return for an Oral Glucose Tolerance Test while fasting.

Additionally, further tests such as genetic testing or autoantibodies tests may sometimes be needed to confirm the type of diabetes.


Each test to detect diabetes and prediabetes uses a different measurement. Usually, your doctor will use a second test to confirm you have diabetes.

The following test results typically indicate if you have prediabetes, or have diabetes. These values may vary slightly. In addition, healthcare providers rely on more than one test to diagnose. If you are pregnant, some tests use different cutoffs.







below 5.7%

99 mg/dL or below

139 mg/dL or below



5.7% to 6.4%

100 to 125 mg/dL

140 to 199 mg/dL



6.5% or above

126 mg/dL or above

200 mg/dL or above

200 mg/dL or above

* 2 hours after glucose intake
Source: American Diabetes Association

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