Type 2 diabetes mellitus: diagnosis (part 1)

The incidence of diabetes mellitus (DM) is steadily increasing. Every 10-15 years in all countries of the world, the number of patients with diabetes is doubled. So, the annual increase in the number of patients with diabetes in the United States is approximately 100,000 people.   

The prevalence of diabetes on average is 1-8.6%, the incidence in children and adolescents is approximately 0.1-0.3%. Given the undiagnosed forms (according to the literature, their share reaches 29–32% of the total prevalence of diabetes), this number may reach 6% in some countries. According to estimates, in 2002 about 120 million people were ill in the world of diabetes. According to the International Diabetes Federation (IDF) (The International Diabetes Federation), the number of patients with diabetes among adults (20–79 years) in the world by 2030 will be 439 million people.

DM is one of the main causes of blindness. Diabetic nephropathy is considered the leading cause of chronic renal failure (CRF) in the USA (more than 40% of new cases), Japan. Among the causes of death, diabetes mellitus takes 3rd place after cardiovascular and oncological diseases.      

Thus, there is no doubt that diabetes is a medical and social problem. In Russia, according to statistics, patients with type 2 diabetes, strictly monitoring the medication, diet, weight, and also due to careful medical supervision and control, often live several years longer than conditionally “healthy” ones.   

At the heart of this series of articles on the diagnosis and treatment of diabetes is the Stewart Tomlinson BMJ Learning training course – just-in-time training. Therefore, the information presented is a reflection of the British recommendations for the diagnosis and treatment of this disease. A key feature of these recommendations is their validity in terms of evidence-based medicine. This circumstance must be taken into account when prescribing treatment to patients and correlated with the National Clinical Recommendations for the treatment of diabetes mellitus.

What is diabetes?

The diagnosis of diabetes mellitus is made on the basis of determining an increased blood glucose level (fasting plasma glucose level of venous blood ≥7.0 mmol / L or glucose level in a random sample of venous blood plasma ≥11.1 mmol / L of not less than 2 times). High blood sugar can cause intense thirst and polyuria (excessive formation and excretion of urine), weight loss, and blurred vision. However, type 2 diabetes is often asymptomatic 1 .

Who develops diabetes?

About 3.9% of the adult population suffers from diabetes. In the UK, this amounts to 2.5 million people, approximately 85-90% of whom have type 2 diabetes. 

On average, there are 72 patients with a diagnosis of diabetes per general practitioner.

The main risk factors for the development of type diabetes :

  • age over 40;
  • obesity (especially central obesity); 
  • Asian, African or Afro-Caribbean descent;
  • arterial hypertension or cardiovascular disease in the past; 
  • family history of diabetes mellitus or cardiovascular disease;
  • a history of gestational diabetes or the birth of a large child (birth weight> 4 kg);  
  • pregnancy.

Other, less common causes of diabetes include:

  • pancreatic diseases (e.g., chronic pancreatitis or cystic fibrosis);   
  • medication (e.g., corticosteroids or thiazides);
  • dysfunction of the endocrine glands (for example, Itsenko- Cushing’s disease or acromegaly);
  • genetic diseases (e.g., Turner syndrome or Down syndrome). 

Why is type 2 diabetes developing?

The causes of type 2 diabetes are:

  • the gradual destruction of pancreatic beta cells;
  • resistance to insulin.

The normal physiological response of pancreatic beta cells to glucose consists of 2 phases:

  • Initial rapid secretion of insulin, which lasts 5-10 minutes.
  • The second phase of the insulin response, which is a continuous pulsating production of insulin, begins 10-20 minutes after the onset of glucose exposure to beta cells.

With the destruction of beta cells in patients with type 2 diabetes, 4,5 , the first phase of the insulin response weakens and slows down. During the second phase, the frequency of insulin release decreases. Both genetic and external factors cause destruction of beta cells: identical twins have a high concordance for diabetes. Pima Indians have a high incidence of diabetes. In this group, impaired insulin secretion in response to glucose is associated with a high fat content in the diet.     

Insulin resistance 6-10 is characterized by a reduced ability of secreted insulin to exert a biological effect on adipose tissue, liver and skeletal muscle. This condition develops in approximately 90% of patients with type 2 diabetes. 

Insulin resistance is caused by both genetic and external factors:

  • concordance for diabetes in identical twins is from 45 to 96%;
  • insulin resistance is associated with central obesity and low physical activity. 

How to diagnose diabetes?

Disease history

In many patients, type 2 diabetes is asymptomatic. Often, several years pass before the patient is given an accurate diagnosis 3 . Diabetes should always be suspected if there are risk factors (for example, if there is a family history of diabetes).

Symptoms of type 2 diabetes are similar to manifestations of type 1 diabetes, but they develop more slowly and gradually:

  • thirst;
  • polyuria;
  • Nocturia (more urine is released at night than during the day);
  • urinary incontinence;
  • apathy, lethargy and malaise; 
  • weight loss;
  • candida vulvovaginitis in women (thrush);
  • balanitis in men.

In patients who came to the initial appointment with a doctor, they may be detected for the first time or a long time of complication of diabetes can be observed. Therefore, in the diagnosis of diabetes, it is imperative to inquire about the symptoms suggesting the presence of the following most common micro- and macrovascular complications:

  • coronary artery disease;
  • a stroke or transient cerebrovascular accident; 
  • peripheral vascular disease;
  • erectile disfunction;
  • retinopathy (non-inflammatory lesion of the retina); 
  • neuropathy (nerve damage, regardless of cause);
  • nephropathy – damage to the kidneys (analysis of urine using a test strip can reveal proteinuria – a protein in the urine).  

During the initial examination of the patient, the possible causes of diabetes mellitus should be excluded and complications detected.

During the examination, it is recommended to do the following:

  • measurement of weight, height and body mass index; 
  • blood pressure measurement;
  • comprehensive eye examination (including screening for retinal changes);
  • study of the cardiovascular system;
  • examination of the feet (including palpation of the pulse on the peripheral arteries and detection of sensory neuropathy).

The purpose of the initial examination should be to identify micro- and macrovascular complications, which often already exist in a patient with diabetes at the time of going to the doctor.

Eye examination
For patients with type 2 diabetes, the National Institute for Health and Clinical Excellence (NICE) of the United Kingdom gives the following recommendations 11 :

  • primary ophthalmoscopy with an enlarged pupil should be performed as soon as possible after the detection of diabetes;
  • subsequent eye examinations are performed once a year or more often in the presence of retinopathy or its progressive course;
  • When planning pregnancy, women with diabetes need to undergo a comprehensive eye examination, and the doctor should inform them of the increased risk of developing or progressing retinopathy. 

Reverse ophthalmoscopy for dilated pupils by an ophthalmologist is an adequate screening method for detecting retinopathy. 

Foot examination

Patients with diabetes should undergo a thorough examination of the feet when confirming the diagnosis and then at least 1 time per year. A similar program can reduce the incidence of foot ulcers and amputations by 44–85% 12 . It is necessary to identify patients with a high risk of developing complications on the feet with diabetes in order to provide them with detailed information, to ensure regular treatment of foot diseases and special shoes, the wearing of which will reduce the risk of ulcers.  

How should the examination of the feet

This examination should include the following procedures:

  • checking the sensitivity of the feet with a 10-gram monofilament or checking the vibration sensitivity of the feet;
  • checking the structure and biomechanics of the feet;
  • assessment of the state of blood vessels (palpation to determine the presence or absence of a pulse in the arteries of the feet);
  • skin integrity check;
  • assessment of the correct selection of shoes.

Leave a Reply

Your email address will not be published. Required fields are marked *