Diabetes is an endocrine disease caused by a lack of insulin or reduced insulin effectiveness. The main metabolic derangement is hyperglycaemia, which can lead to serious microvascular and macrovascular complications.
Both Type 1 diabetes (T1DM) and Type 2 diabetes (T2DM) have the same long-term complications. Diabetes (especially T2DM) will most frequently be diagnosed on screening. Some T1DM patients may present in Diabetic Ketoacidosis (DKA), while some T2DM patients may present in Hyperosmolar Hyperglycemic State (HHS).
Definition of terms
| Type | Description |
|---|---|
| Type I Diabetes Mellitus (T1DM) | Caused by autoimmune destruction of beta cells. Always requires insulin, and patients appear lean with an early onset. |
| Type II Diabetes Mellitus (T2DM) | Caused by insulin resistance. Controlled by appropriate diet and exercise and/or oral meds. May require insulin. Chronically overweight/obese patient. |
| Maturity Onset Diabetes of the Young (MODY) | An autosomal dominant form of T2DM that affects young individuals |
| Impaired Glucose Regulation (IGR) | Includes Impaired Glucose Tolerance (IGT) and Impaired Fasting Glucose (IFG) |
| Impaired fasting glucose (IFG) | Fasting glucose 6.1 – 7 mmol/L due to hepatic insulin resistance |
| Impaired glucose tolerance (IGT) | 2-hour OGTT 7.8 – 11.1 mmol/L due to muscle insulin resistance. More likely to develop T2DM and cardiovascular disease than IFG. |
Type 1 diabetes vs Type 2 diabetes
| Type 1 diabetes | Type 2 diabetes | |
|---|---|---|
| Patient | Onset before puberty | Usually older patients |
| Genetics | HLA-D3 and HLA-D4 phenotypes | No HLA association |
| Cause | Autoimmune destruction of beta cells | Insulin resistance and beta-cell dysfunction |
| Presentation | Polydypsia, polyuria, weight loss, ketosis | Asymptomatic, complications e.g. myocardial infarction |
- Key signs and symptoms
- Polyuria
- Polydipsia
- Polyphagia
- Complications
- Acute complications
- Microvascular complications
- Diabetic retinopathy
- Diabetic nephropathy
- Diabetic neuropathy
- Macrovascular complications
- Coronary artery disease
- Cerebrovascular disease
- Peripheral artery disease
- Other complications
- Diabetic foot
- Infections