Diabetes Mellitus and its Complications

Definition

Diabetes Mellitus is a chronic metabolic disorder characterised by persistent hyperglycaemia due to either insufficient insulin production by the pancreas or inadequate utilisation of insulin by the body's cells. There are three main types: Type 1 Diabetes Mellitus (T1DM), Type 2 Diabetes Mellitus (T2DM), and Gestational Diabetes Mellitus (GDM).

Aetiology

The causes of Diabetes Mellitus vary depending on the type:

Type 1 Diabetes Mellitus: Caused by autoimmune destruction of insulin-producing beta cells in the pancreas.
Type 2 Diabetes Mellitus: Caused by a combination of insulin resistance and beta cell dysfunction.
Gestational Diabetes Mellitus: Caused by hormonal changes during pregnancy that result in insulin resistance.

Pathophysiology

In Diabetes Mellitus, hyperglycaemia occurs due to:

Reduced insulin production (T1DM)
Insulin resistance and impaired insulin secretion (T2DM)
Increased insulin resistance during pregnancy (GDM)

Persistent hyperglycaemia leads to metabolic disturbances, including impaired glucose uptake by cells, increased glucose production by the liver, and altered lipid and protein metabolism. Chronic hyperglycaemia can result in long-term damage to various organs and tissues.

Risk Factors

Family history of diabetes
Obesity
Physical inactivity
Age (older than 45 years)
Ethnicity (higher risk in certain ethnic groups)
History of gestational diabetes
Hypertension
Hyperlipidaemia

Signs and Symptoms

Common signs and symptoms of Diabetes Mellitus include:

Increased thirst (polydipsia)
Frequent urination (polyuria)
Extreme hunger (polyphagia)
Unexplained weight loss
Fatigue
Blurred vision
Slow-healing sores
Frequent infections

Investigations

Fasting blood glucose: To measure blood glucose levels after an overnight fast
HbA1c test: To assess average blood glucose levels over the past 2-3 months
Oral glucose tolerance test (OGTT): To measure blood glucose levels before and after consuming a glucose drink
Random blood glucose test: To measure blood glucose levels at any time of the day
Urine tests: To check for the presence of glucose and ketones
Lipid profile: To assess cholesterol and triglyceride levels
Kidney function tests: To evaluate renal function
Fundoscopy: To check for diabetic retinopathy

Management

Primary Care Management

Lifestyle modifications: Encouraging a healthy diet, regular physical activity, and weight management
Monitoring blood glucose levels: Regular self-monitoring of blood glucose (SMBG)
Medications: Oral hypoglycaemic agents (e.g., metformin, sulfonylureas) for T2DM; insulin therapy for T1DM and advanced T2DM
Blood pressure control: Using antihypertensive medications to manage hypertension
Lipid management: Statins to control dyslipidaemia
Education: Providing information on diabetes management, healthy eating, and physical activity
Regular follow-up: Monitoring for complications and adjusting treatment as needed

Specialist Management

Insulin therapy: Tailoring insulin regimens for optimal glucose control in T1DM and advanced T2DM
Continuous glucose monitoring (CGM): To provide real-time glucose readings and trends
Management of complications: Addressing issues such as diabetic retinopathy, nephropathy, neuropathy, and cardiovascular disease
Endocrinologist referral: For complex cases and ongoing specialist care
Multidisciplinary team approach: Involving dietitians, diabetes educators, podiatrists, and ophthalmologists

Complications

Chronic hyperglycaemia in diabetes can lead to various complications, including:

Diabetic retinopathy: Damage to the blood vessels in the retina, leading to vision loss
Diabetic nephropathy: Kidney damage that can progress to end-stage renal disease
Diabetic neuropathy: Nerve damage causing pain, tingling, and numbness, particularly in the feet
Cardiovascular disease: Increased risk of heart attack, stroke, and peripheral artery disease
Diabetic foot: Ulcers, infections, and, in severe cases, gangrene leading to amputation
Hypoglycaemia: Low blood glucose levels causing symptoms such as shaking, sweating, and confusion
Hyperglycaemic hyperosmolar state (HHS) and diabetic ketoacidosis (DKA): Acute, life-threatening complications of diabetes

Example Management for Diabetes Mellitus

A patient diagnosed with T2DM presenting with hyperglycaemia and hypertension should be managed with lifestyle modifications such as a healthy diet, regular physical activity, and weight management. Initial pharmacological treatment may include metformin to control blood glucose levels and an ACE inhibitor or angiotensin II receptor blocker (ARB) for blood pressure control. Regular monitoring of blood glucose levels, kidney function, and lipid profile is essential. The patient should also be educated on the importance of medication adherence, self-monitoring of blood glucose, and recognising signs of hypoglycaemia. Referral to a diabetes educator and dietitian may be beneficial for comprehensive management.

References

NICE. (2024). Type 2 Diabetes in Adults: Management. Retrieved from NICE
NICE. (2024). Type 1 Diabetes in Adults: Diagnosis and Management. Retrieved from NICE
NHS. (2023). Diabetes. Retrieved from NHS
American Diabetes Association (ADA). (2022). Standards of Medical Care in Diabetes. Retrieved from ADA
International Diabetes Federation (IDF). (2021). Global Guideline for Type 2 Diabetes. Retrieved from IDF