What is Diabetes mellitus?

Healthful Vitality | 08/13/2021 | What is Diabetes mellitus?

Diabetes mellitus, also called diabetes, is a chronic metabolic disorder. It is a condition characterized by high blood glucose levels. Diabetes mellitus may occur due to insulin deficiency, faulty secretion, resistance, or a combination of all these factors.

Understanding diabetes mellitus

It is vital to understand that diabetes mellitus is not just about high blood sugar. It is a much broader metabolic disorder. The blood sugar level is just one of the reliable ways of measuring the disease severity. Else, in most of those living with diabetes, there are disturbances of fats, proteins, and micronutrients, too.

Insulin is a hormone that enables the entry of glucose molecules into the cells. It also promotes other anabolic processes. In diabetes, despite the high blood glucose levels, body cells are starving as glucose fails to enter the cells.

Consistently high blood glucose levels cause severe damage to various body cells. It appears that nerve cells and blood vessels are especially susceptible to high blood glucose levels. Thus, poorly managed diabetes increases the risk of heart disease, kidney disease, stroke, retinopathy, neuropathies, and much more.

Blood glucose regulation

In a healthy person, fasting blood glucose levels should be between 60-120 mg/dl. Even in healthy people, blood glucose levels may rise above this range after a high-carb diet. However, the body will quickly bring it back to the normal range by secreting more insulin. Additionally, it is worth knowing that carbs are the primary source of blood glucose. However, if needed, the body can also produce carbs from fats and proteins.

The two most vital hormones that play a crucial role in blood glucose regulation are insulin and glucagon. Both these hormones are produced in the pancreas by the different kinds of cells. For example, beta-cells produce insulin in the pancreas.

The role of insulin is primarily promoting glucose metabolism. It thus instructs body cells to take glucose according to their needs. In addition, it would help store extra glucose in the skeletal muscles and the liver.

Glucagon and insulin

Glucagon is just the opposite of insulin. If blood glucose levels go too low, it instructs various body cells to release as much glucose as possible. It may also instruct the liver to produce glucose using another nutrient.

Insulin and glucagon together help maintain the balance in glucose levels in the body. However, it is worth noticing that there are other body structures involved in blood glucose regulation. For example, intestines may instruct the pancreas to produce more insulin when and as needed. Intestines also play a vital role in appetite regulation.

Why diabetes mellitus occurs?

There is no straightforward answer to this. It will depend on the type of diabetes. Type 1 diabetes (T1D) is an autoimmune condition. A condition when immune cells start attacking healthy insulin-producing beta-cells in the body. On the contrary, Type 2 diabetes (T2D) appears to be a lifestyle disorder. T2D might be caused by surplus calorie intake, low-calorie expenditure, leading to faulty insulin secretion and resistance.

How is diabetes diagnosed?

Diabetes is always diagnosed by measuring blood glucose levels. However, three different tests are commonly used, and each has its pros and cons.

1. FPG (Fasting plasma glucose) is a test done after fasting for at least 8 hours, but no more than 12 hours. Thus, this test is often done in the morning, as a person is naturally fasting during the night. An FPG ≥126 mg/dL confirms the diagnosis of diabetes.
2. 2-hours Oral Glucose Tolerance Test (OGTT) – this test is especially useful if FPG results are inconsistent and fail to confirm or exclude diabetes. In such a case, a doctor would give a person 75 g of glucose dissolved in water. Then, doctors would measure the plasma level of glucose after 2-hours. Value of PG ≥200 mg/dL confirms the diagnosis of diabetes.
3. A1C– this test shows how much glucose has accumulated in the red blood cells or tied up with hemoglobulin. This test generally indicates the blood glucose level for the last 2-3 months. The value of A1C ≥6.5% confirms the diagnosis. This test is especially useful for monitoring the severity of diabetes and also the effectiveness of any therapy.

Classification of diabetes mellitus

There are numerous types of diabetes mellitus, and they are classified into four groups:

1. Type 1 diabetes (T1D)
2. Type 2 diabetes (T2D)
3. Gestational diabetes – diabetes diagnosed during the second or third trimester of pregnancy
4. Other types like MODY, LADA, and diabetes caused by medications like corticosteroids

T1D and T2D are the two most common types of diabetes. Other types of diabetes only affect a small number of people. For example, gestational diabetes affects only during pregnancy, and later it may progress to T2D. This article looks at the two most common types of diabetes.

Type 1 diabetes

Little less than 10% of all cases of diabetes are due to T1D.

It is an autoimmune disease. T1D is a condition when the body’s immunity starts attacking insulin-producing beta-cell in the pancreas. Thus, it ultimately leads to severe insulin deficiency. Since no medications can effectively stop this autoimmune attack, insulin replacement therapy remains its mainline treatment.

Earlier, this type was often called “insulin-dependent diabetes” or “juvenile-onset diabetes.”

It is a diabetes of young. Most people would be diagnosed with this condition within the age of 4 to 14 years. Its incidence goes down with the onset of puberty. About 85% of people living with T1D will be diagnosed before the age of 20. Nevertheless, in a small number of cases, it may occur in older adults.

It is also defined as diabetes of young and lean. Most people living with it are not essentially obese.

Causes of T1D

There is a poor understanding of what causes it. But it appears to be a mix of genetic risk factors and environmental factors. Studies show that it often runs in families. It has a high association with genes like DQA and DQB. However, it has a weak association with genetics. Thus, other factors like environmental toxins and viral infections also appear to increase its risk.

Diagnostic tests of T1D

A1C or FPG or OGTT test may help confirm diabetes. However, the tests below may help confirm that it is T1D.

There is a panel of islet antibodies test available. It may be used to detect its risk early enough and take measures. However, it is worth noticing that these tests are reserved for high-risk individuals. It is because many people with positive antibody tests may not develop T1D.

Additionally, undetectable levels of C-peptide may help differentiate it from T2D. C-peptide is a precursor for insulin production. Therefore, its absence says about the lack of insulin production.

Signs and symptoms of T1D

This diabetes is first diagnosed in individuals younger than 20 years of age, which is rare in the case of T2D. Most people would be diagnosed before puberty, between the age of 4 to 14 years. It also has a very sudden onset. It suddenly causes an excessive urge to eat, pee, and drink. As a result, a child may develop weight loss, fatigue, and feeling sick, and even blurry vision.

It is not rare for T1D to be diagnosed when diabetic ketoacidosis has started. Notably, it causes symptoms of acute abdomen with severe stomach pain, nausea, vomiting. T1D also causes dizziness. A typical fruity smell in breath may help differentiate it from the acute abdomen.

Treatment of T1D

Since in T1D, there is a lack of insulin in the body, insulin therapy remains its mainline of treatment. It is not rare these days to use an insulin pump. However, due to high insulin costs, managing the condition is challenging in low-resource settings. At present, there is no cure for the disease, and oral drugs have limited or no role.

Type 2 diabetes

Type 2 diabetes is the most common type of diabetes. More than 85% of all cases of diabetes are due to T2D.

Causes of T2D

It is a lifestyle disorder. A combination of factors causes it. Notably, it appears that obesity is the most significant risk factor for the condition. High-calorie intake, along with low-calorie expenditure, causes the disease. Wrong dietary choices, like high consumption of processed carbs, may further increase its risk.

Other risk factors are family history, hypertension, PCOS, and age. It is a disease that develops gradually over the years and perhaps decades.

As it is a lifestyle disorder with gradual onset, it is also among the preventable illnesses.

Diagnostic tests of T2D

Blood glucose tests would help confirm diabetes. The absence of islet antibodies and the presence of C-peptide may indicate that insulin resistance is causing diabetes. Age of onset may also help it differentiate from other types of diabetes.

Signs and symptoms of T2D

T2D may show only mild signs like increased thirst, appetite, and peeing. Some may show early symptoms of peripheral neuropathy. T2D might be detected due to the presence of poorly healing ulcers. It is often diagnosed late when some of the chronic complications have started to show.

Its onset is gradual, and symptoms in the early stages are very mild. That is why about half of all those living with T2D remain undiagnosed. Therefore, its accidental diagnose is not rare. In addition, people are often diagnosed with it during their routine health check or blood glucose test due to other health conditions like impending surgery.

T2D treatment

T2D is managed by combining oral drugs and lifestyle changes. In most people diagnosed with T2D, treatment will begin with metformin. Metformin helps reduce insulin resistance. However, as the disease progresses, doctors may add other medications. There are tens of other drugs. Doctors would generally recommend other drugs depending on their general health.

Lifestyle interventions like weight loss, reducing intake of fast-absorbing carbs, eating in small portions, avoiding sugar drinks, eating healthy fats are essential parts of the treatment.

If drug therapy and lifestyle interventions fail, then a doctor may also initiate insulin therapy.

Prevention and Reversal of T2D

Since T2D is a lifestyle disorder, it is also highly preventable. Diabetes prevention studies show that even losing 5-7% of body weight may considerably reduce its risk. Further, exercising for 30-60 minutes a day for five days a week may help. Both these measures must be combined with calorie restrictions.

Just a few decades back, doctors did not believe in terms like diabetes reversal. However, now studies show that its reversal or prolonged remission is possible. Studies show that a very low-calorie liquid diet, like an 800-calorie diet combined with weight loss, may help reverse diabetes in many cases.

Further, T2D may be reversed with the help of bariatric surgery in a very obese individual with a BMI of above 40.

Researchers are also exploring other ways of T2D reversal, like duodenal mucosal resurfacing (DMR) with the help of high-pressure water applied by a laparoscope. This helps remove the upper and thickened layer of the duodenum, resulting in improvement in blood glucose regulation.

Prediabetes

In recent years, researchers have paid great attention to the early identification of various chronic ailments. For example, prediabetes is a borderline condition. A condition when a person is still not having T2D but is at significant risk of developing in the future. At this stage, lifestyle interventions may help prevent the disease.

Thus, FPG between 100 to 125 mg/dL or A1C between 5.7% and 6.4%, or OGTT result between 140 to 199 mg/dL indicates prediabetes. One may use just any one of the tests to confirm the diagnosis.

Prediabetes is reversible through extensive dietary measures like calorie restrictions, nutritional changes (restricting carb intake), exercise, and weight loss.

Diabetes complications

The main reason to maintain blood glucose levels is to prevent diabetes-related complications. These complications are the primary cause of disability and reduced lifespan.

Acute complications

One of the acute complications of very high blood glucose (like above 200 mg/dL) and poorly controlled diabetes is diabetic ketoacidosis (DKA). In this condition, high blood glucose causes severe dehydration. Since the glucose cannot enter body cells, the liver starts producing ketone bodies from fats for fulfilling energy needs. Since these ketone bodies are acidic, their extremely high-level cause electrolyte and pH disbalance causing severe disease. It may cause acute abdomen, fatigue, fruity odor, dizziness, and even loss of consciousness.

Another common acute complication is hypoglycemia. It is primarily a result of high insulin doses. It may cause sudden weakness, shivering, seizures, and quick loss of consciousness. If identified early enough, it is readily managed with sugary drinks or glucose tablets.

Chronic complications

Poorly managed diabetes may cause a range of chronic complications. Most of these complications are due to damage caused by high blood glucose to small and large blood vessels and nerves. Thus, diabetes increases the risk of heart attack and stroke. Diabetes is the leading cause of chronic kidney disease. Besides, diabetes often causes poorly healing ulcers. Diabetes is also the primary cause of non-traumatic amputations. Indeed, diabetes is the leading cause of various neuropathies.

To conclude diabetes mellitus is more commonly known simply as diabetes. Diabetes mellitus is a complex disorder caused by many reasons. Nonetheless, in about 85% of cases, it is T2D, a kind of lifestyle disease. Thus, diabetes mellitus is highly preventable in the majority of cases.

Related Article: Pre-Diabetic Diet