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Sonographic Evaluation of Peripheral Nerves in Type 2 Diabetes Mellitus

Published on Jan 05, 2023 and last reviewed on Jan 24, 2023   -  6 min read


Ultrasound examination is crucial to prevent neurological complications associated with type 2 diabetes mellitus. Read this article for more details.


Carbohydrates, proteins, vitamins, and minerals are essential macronutrients that play a vital role in various body functions. To be efficiently utilized, these macronutrients must be metabolized appropriately in the body. Carbohydrates are the prime source of energy and are available in various forms. Glucose is one of the essential carbohydrates found in our daily diet and a simple breakdown product of carbohydrates. It is also produced and stored in the liver. This glucose is absorbed into the bloodstream, from where it reaches individual cells to provide energy for vital body functions. Insulin is a hormone secreted by the pancreas, which is the crucial regulator of blood glucose. It also helps glucose to enter the cells. The pancreas secretes insulin when the glucose level is high in the blood. Insulin signals the liver and other body cells to store or utilize glucose to produce energy, thereby lowering the blood glucose level. An impaired insulin production or blood glucose regulation would result in a metabolic disorder known as diabetes mellitus.

What Is Diabetes Mellitus?

Diabetes mellitus is a metabolic disease that results in excess blood glucose or blood sugar levels. It may occur due to impaired insulin production or improper insulin usage by the cells in the body. As a result, the glucose tends to remain unused in the bloodstream, thereby increasing its level. Uncontrolled diabetes could affect organs such as kidneys, heart, and eyes and cause potential complications.

What Are the Types of Diabetes Mellitus?

Diabetes mellitus can be classified as:

  • Prediabetes: Prediabetes is a state where the blood glucose level is high but not high enough to be diabetes. Individuals with prediabetes are more prone to type 2 diabetes mellitus and cardiovascular diseases. However, lifestyle changes and diet modifications can prevent the development of overt diabetes.

  • Type 1 Diabetes: It is also known as insulin-dependent diabetes or juvenile-onset diabetes. The symptoms usually begin in childhood. It is an autoimmune condition where the body regards the pancreas as a foreign body and attacks it with antibodies. As a result, insufficient insulin is produced.

  • Type 2 Diabetes: It is known as adult-onset or insulin-resistant diabetes mellitus. The insulin, though produced, may not be sufficient, or the body is unable to use the insulin produced.

  • Gestational Diabetes: Diabetes is a common acquired condition during pregnancy. Uncontrolled diabetes during pregnancy may be harmful to the unborn baby.

  • Other Forms: Diabetes may also occur as an adverse effect of certain medications, associated conditions, or other surgeries. They may be temporary and reversible or permanent.

What Is Type 2 Diabetes Mellitus?

Type 2 diabetes mellitus is usually seen in adults; however, a steep rise is seen in individuals over 20 years of age. The reason for this incline is obesity and unhealthy dietary indulgences. In this condition, some insulin is produced by the pancreas; however, the body cells are unable to utilize it. Hence this type is also known as insulin-resistant diabetes. Though the complications associated with type 2 diabetes are less, it is one of the leading causes of stroke (brain damage that results due to reduced blood supply to the brain) and neurological complications.

What Are the Risk Factors Associated With Type 2 Diabetes Mellitus?

The following risk factors are associated with type 2 diabetes mellitus:

  • Obesity is one of the main risk factors for type 2 diabetes mellitus.

  • Increasing waist circumference indicates higher abdominal fat, increasing predisposition to type 2 diabetes.

  • Reduced physical activity.

  • Positive family history.

  • High cholesterol.

  • Age.

  • Individuals with prediabetes.

  • Women with gestational diabetes.

What Are the Symptoms of Diabetes Mellitus?

The signs and symptoms are mentioned below:

  • Increased thirst and hunger.

  • Frequent urination.

  • Fatigue.

  • Weight loss.

  • Delayed wound healing.

  • Repeated infections.

  • Feeling of numbness or tingling sensations in the upper and lower limbs.

What Are the Complications?

Uncontrolled and chronic type 2 diabetes mellitus can affect organs such as the heart, kidney, nerves, blood vessels, and eyes and cause fatal complications. The long-term complications are mentioned below:

  • Cardiovascular Diseases - Uncontrolled diabetes increases the risk of heart disease and stroke. It also increases the triglycerides and cholesterol levels, thereby increasing the possibility of developing atherosclerosis (blocked blood vessels), resulting in angina or heart attack.

  • Kidney Diseases - Uncontrolled diabetes may lead to chronic renal diseases and end-stage renal failure.

  • Vision Problems - Glaucoma (an eye condition that causes blindness), cataracts (the lens in the eyes becomes cloudy), and diabetic retinopathy (a complication of diabetes resulting in eye damage) are common eye complications as diabetes damages small blood vessels. This may result in impaired vision or progressively complete blindness.

  • Skin Ulcers - Non-healing ulcers, particularly in the foot, may occur due to compromised blood circulation and neuronal impairment. Untreated ulcers may become infected and form gangrene (tissue death due to loss of blood supply), which may require amputation (removal of a body part).

  • Psychological Problems - A higher incidence of anxiety, depression, and stress is associated with diabetic patients. Studies have shown a positive correlation between diabetes and psychological conditions like dementia (affects memory) and Alzheimer’s disease (a progressive neurologic disease that impairs memory and other mental abilities).

  • Intraoral Complications - Oral ulcers, tooth mobility, and poor gum health are most commonly seen in uncontrolled diabetes patients.

What Is Diabetic Neuropathy?

Diabetic neuropathy is one of the most common complications of chronic uncontrolled diabetes. High blood sugar can cause damage to the peripheral nerves (of the limbs) and even major organs such as the heart. It is one of the most severe complications that affects at least 50 % of diabetic patients. Peripheral neuropathy is common; symptoms include numbness and tingling sensation in the extremities. Severe cases of peripheral neuropathy may be characterized by intense pain and ulcerations resulting in disability. The symptoms differ based on the organ affected. Irregular heart rhythm, nausea, constipation, and diarrhea are some of the symptoms when the heart and digestive systems are affected, respectively. Erectile dysfunction may occur in males if the nerves of the penis are affected.

Neuropathic complications can result in permanent and irreversible damage if not treated earlier. Hence diagnosing neurological complications promptly is essential to prevent fatalities. Furthermore, early recognition of these complications can help reverse the condition, improving the prognosis and enabling the patient to lead a healthy life.

How to Diagnose Diabetic Neuropathy?

A detailed medical history and thorough physical examination can help identify the signs and symptoms of neuronal damage. The reflexes, core muscle strength, and response to touch, pain, and other sensory stimuli can be assessed to determine the extent of the damage. Nerve conduction tests and electromyography can evaluate the electrical activity of the nerves and the muscles.

What Is the Role of Ultrasound in Evaluating the Peripheral Nerves in Type 2 Diabetes Mellitus?

The diagnosis of diabetic neuropathy is usually based on clinical symptoms and using a nerve conduction study. However, nerve conduction study is a time-consuming procedure and is invasive and hence not well tolerated by the patients. Therefore a less invasive technique to image the nerves was the need of the hour. Ultrasound is used widely to image various organs and tissues of the body. It is cost-effective, painless, noninvasive, straightforward, and quick. The portability and real-time imaging complement its usage universally. Hence with advanced high-resolution ultrasound techniques, peripheral nerves could easily be imaged and evaluated.

Ultrasound is highly beneficial in diagnosing inflammation and swelling of the nerves, their precise location, and their extent. Ultrasound uses sound waves to create images of the body organ’s and tissues. A small device known as a transducer emits sound waves into the body, which bounce back upon hitting the internal structure. A computer processes this reflected sound wave into images depending on the speed and time it takes to reflect. A normal peripheral nerve on ultrasound appears as parallel hyperechoic lines (they bounce back too many sound waves). In type 2 diabetes mellitus, there was significant nerve enlargement, which appeared hypoechoic (decreased reflecting sound waves suggesting a solid lesion). In addition, there was a substantial increase in the cross-sectional area of the nerves. Ultrasound has been highly beneficial in detecting subclinical nerve involvement and neuronal abnormalities in patients with normal nerve conduction studies.


Though nerve conduction study is widely preferred to diagnose neurological abnormalities, ultrasound has proved equally valuable and efficient in diagnosing peripheral neuropathy in type 2 diabetes mellitus. Therefore, considering the advantages of ultrasound over nerve conduction study, sonography seems to be a promising diagnostic tool in diabetic neuropathy.

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Last reviewed at:
24 Jan 2023  -  6 min read




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