DIABETES MELLITUS

DIABETES MELLITUS

DEFINATION 

TREATMENT &CONTROL

TYPES/CLASSIFICATION OF   DIABETES MELITTUS  .

Diabetes mellitus is a disease caused by deficiency or diminished effectiveness of endogenous insulin. It is characterised by hyperglycaemia, deranged metabolism and sequelae predominantly affecting the vasculature. The main types of diabetes mellitus are:

• Type 1 diabetes mellitus: results from the body's failure to produce sufficient insulin.
• Type 2 diabetes mellitus: results from resistance to the insulin, often initially with normal or increased levels of circulating insulin.
• Gestational diabetes: pregnant women who have never had diabetes before but who have high blood glucose levels during pregnancy are said to have gestational diabetes. Gestational diabetes affects about 4% of all pregnant women. It may precede development of type 2 (or rarely type 1) diabetes.
• Maturity-onset diabetes of the young (MODY) includes several forms of diabetes with monogenetic defects of beta-cell function (impaired insulin secretion), usually manifesting as mild hyperglycaemia at a young age, and usually inherited in an autosomal-dominant manner.
• Secondary diabetes: accounts for only 1-2% of patients with diabetes mellitus. Causes include:
  • Pancreatic disease: cystic fibrosis, chronic pancreatitis, pancreatectomy, carcinoma of the pancreas.
  • Endocrine: Cushing's syndrome, acromegaly, thyrotoxicosis, phaeochromocytoma, glucagonoma.
  • Drug-induced: thiazide diuretics, corticosteroids, atypical antipsychotics, antiretroviral protease inhibitors.
  • Congenital lipodystrophy.
  • Acanthosis nigricans.
  • Genetic: Wolfram's syndrome (which is also referred to as DIDMOAD: diabetes insipidus, diabetes mellitus, optic atrophy and deafness),Friedreich's ataxia, dystrophia myotonica, haemochromatosis, glycogen storage diseases.

Some patients with type 2 diabetes require insulin, so the old terms of insulin-dependent diabetes mellitus (IDDM) for type 1 diabetes and non-insulin-dependent diabetes mellitus (NIDDM) for type 2 diabetes are inappropriate. Type 2 diabetes is increasingly diagnosed in children and adolescents and so the old term maturity-onset diabetes for type 2 diabetes is also inappropriate.

Type 1 diabetes mellitus

The development of type 1 diabetes mellitus is based on a combination of a genetic predisposition and an autoimmune process that results in gradual destruction of the beta cells of the pancreas, leading to absolute insulin deficiency. There is usually a pre-diabetic phase where autoimmunity has already developed but with no clinically apparent insulin dependency. Insulin autoantibodies can be detected in genetically predisposed individuals as early as 6-12 months of age.
Possible triggers for the process may include viruses, dietary factors, environmental toxins, and emotional or physical stress. Early cessation of breast-feeding has also been linked to increased risk of developing type 1 diabetes, but the association is unproven and controversial.

• Approximately 15% of those with diabetes have type 1 diabetes - usually juvenile-onset, but it may occur at any age. It may be associated with other autoimmune diseases. It is characterised by insulin deficiency.
• There is 30-50% concordance in identical twins and a positive family history in 10% of people with type 1 diabetes. Screening for the diagnosis of diabetes in first-degree relatives of patients with type 1 is therefore reasonable, keeping in mind that the absolute risk is quite low.
• Associated with HLA DR3 and DR4 and islet cell antibodies around the time of diagnosis.
• Patients always need insulin treatment and are prone to ketoacidosis.
• The most at-risk population for type 1 diabetes is Caucasian of northern European ancestry. Incidence is high in Scandinavian people.

Type 2 diabetes mellitus

• Approximately 85% of those with diabetes; they are usually older at presentation (usually >30 years of age) but it is increasingly diagnosed in children and adolescents.
• Type 2 diabetes is associated with excess body weight and physical inactivity.
• All racial groups are affected but there is increased prevalence in people of South Asian, African, African-Caribbean, Polynesian, Middle-Eastern and American-Indian ancestry.
• It is caused by impaired insulin secretion and insulin resistance and has a gradual onset.
• Those with type 2 diabetes may eventually need insulin treatment.

Prevalence^.

• In 2011 there were 2.9 million people with diabetes. It is estimated that 5 million people will have diabetes in the UK by 2025.
• It is estimated that there are around 850,000 people in the UK who have diabetes but have not been diagnosed.
• The UK average prevalence of diabetes in the UK is 4.45% but there are variations between countries and regions.
• The proportion of people with diabetes increases with age.
• However, the incidence of diabetes is increasing in all age groups. Type 1 diabetes is increasing in children (especially those aged <5 years), and type 2 diabetes is increasing, particularly in black and minority ethnic groups.

Risk factors for type 2 diabetes^.

• Obesity, especially central (truncal) obesity.
• Lack of physical activity.
• Ethnicity: people of South Asian, African, African-Caribbean, Polynesian, Middle-Eastern and American-Indian descent are at greater risk of type 2 diabetes, compared with the white population.
• History of gestational diabetes.
• Impaired glucose tolerance.
• Impaired fasting glucose.
• Drug therapy - eg, combined use of a thiazide diuretic with a beta-blocker.
• Low-fibre, high-glycaemic index diet.
• Metabolic syndrome.
• Polycystic ovarian syndrome.
• Family history (2.4-fold increased risk for type 2 diabetes).
• Adults who had low birth weight for gestational age.

Presentation

• Patients with all types of diabetes may present with polyuria, polydipsia, lethargy, boils, pruritus vulvae or with frequent, recurrent or prolonged infections.
• Patients with type 1 diabetes may also present with weight loss, dehydration, ketonuria and hyperventilation. Presentation of type 1 diabetes tends to be acute with a short duration of symptoms.
• Presentation in patients with type 2 diabetes tends to be subacute with a longer duration of symptoms.
• Patients with diabetes may present with acute or chronic complications, as outlined in the section 'Complications', below.

PatientPlus

• Assessment of the Patient with Established Diabetes
• Insulin Regimens
• Audit of Diabetes Care
• Diabetes Diet and Exercise

Diagnosis

• Diabetes may be diagnosed on the basis of one abnormal plasma glucose (random ≥11.1 mmol/L or fasting ≥7 mmol/L) in the presence of diabetic symptoms such as thirst, increased urination, recurrent infections, weight loss, drowsiness and coma.
• In asymptomatic people with an abnormal random plasma glucose, two fasting venous plasma glucose samples in the abnormal range (≥7 mmol/L) are recommended for diagnosis.
• Two-hour venous plasma glucose concentration ≥11.1 mmol/L two hours after 75 g anhydrous glucose in an oral glucose tolerance test (OGTT).
• The World Health Organization (WHO) now recommends that glycated haemoglobin (HbA1c) can be used as a diagnostic test for diabetes. An HbA1c of 48 mmol/mol (6.5%) is recommended as the cut-off point for diagnosing diabetes. A value less than 48 mmol/mol does not exclude diabetes diagnosed using glucose tests.

Management

The management plan for a person with diabetes includes:

• Diabetes education: structured education and self-management (at diagnosis and regularly reviewed and reinforced) to promote awareness.
• Diet and lifestyle: healthy diet, weight loss if the person is overweight, smoking cessation, regular physical exercise.
• Maximising glucose control while minimising adverse effects of treatment, such as hypoglycaemia.
• Reduction of other risk factors for complications of diabetes, including the early detection and management of hypertension, drug treatment to modify lipid levels and consideration of antiplatelet therapy with aspirin.
• Monitoring and early intervention for complications of diabetes, including cardiovascular disease, feet problems, eye problems, kidney problems and neuropathy.