Pathophysiology and Classification of Diabetes Mellitus
Diabetes mellitus is a metabolic disorder characterized by persistent hyperglycemia resulting from defects in insulin secretion, insulin action, or both.
- Type 1 Diabetes Mellitus: Characterized by autoimmune destruction of the pancreatic beta cells, leading to absolute insulin deficiency. Patients require lifelong exogenous insulin replacement for survival.
- Type 2 Diabetes Mellitus: The predominant form encountered in Nigerian clinical settings, marked by peripheral insulin resistance combined with a progressive secretory defect.
- Gestational Diabetes Mellitus: Glucose intolerance onset or first recognition during pregnancy, posing unique risks to both mother and fetus if unmanaged.
Chronically elevated blood glucose damages endothelial cells, leading to widespread microvascular and macrovascular complications.
Clinical Presentation and Diagnostic Evaluation
The classic clinical presentation of uncontrolled diabetes involves the three polys: polyuria (excessive urination), polydipsia (excessive thirst), and polyphagia (excessive hunger), often accompanied by unexplained weight loss. In busy Nigerian outpatient clinics, patients frequently present late with advanced complications like blurry vision, slow-healing tropical ulcers, or severe paresthesia due to peripheral neuropathy.
Diagnosis is confirmed using standardized glycemic thresholds:
- Fasting Plasma Glucose: Equal to or greater than 7.0 mmol/L.
- Random Plasma Glucose: Equal to or greater than 11.1 mmol/L in the presence of classic symptoms.
- Glycated Hemoglobin (HbA1c): Equal to or greater than 6.5%, reflecting average glycemic control over the preceding three months.
Acute and Chronic Complications
Complications of diabetes are broadly divided into acute metabolic emergencies and long-term systemic damage.
Acute Complications
- Diabetic Ketoacidosis (DKA): More common in Type 1 diabetes, featuring severe hyperglycemia, dehydration, metabolic acidosis, and ketonuria.
- Hyperglycemic Hyperosmolar State (HHS): Typically seen in Type 2 diabetes, characterized by profound dehydration and extreme hyperglycemia without significant ketoacidosis.
- Hypoglycemia: Low blood glucose caused by delayed meals, excessive exercise, or mismatched medication doses.
Chronic Complications
- Microvascular: Retinopathy, nephropathy, and neuropathy.
- Macrovascular: Coronary artery disease, cerebrovascular disease, and peripheral arterial disease leading to foot ulcers and gangrene.
Medical and Nursing Management
Management requires a multidisciplinary approach focusing on glycemic control, prevention of complications, and acute crisis stabilization.
- Pharmacotherapy: Oral hypoglycemic agents such as metformin are first-line for Type 2 diabetes. Insulin therapy is mandatory for Type 1 and advanced Type 2.
- Fluid and Electrolyte Balance: In acute emergencies like DKA, aggressive rehydration with normal saline and careful potassium correction take precedence.
- Wound Care: Regular inspection and debridement of diabetic foot ulcers prevent secondary bacterial infections and limb amputation.
- Vital Sign Monitoring: Regular tracking of blood pressure and pulse helps detect cardiovascular strain early.
Patient Education, Diet Therapy, and Self-Monitoring
Empowering patients through targeted education improves long-term outcomes and prevents hospital admissions.
- Dietary Modifications: Emphasize high-fiber local foods, vegetables, and complex carbohydrates while reducing refined sugars and heavy starches like excess fufu or pounded yam.
- Self-Monitoring of Blood Glucose (SMBG): Teach patients how to use glucometers correctly, interpret readings, and maintain a daily logbook.
- Foot Care Education: Instruct patients to inspect their feet daily, wear supportive footwear, avoid walking barefoot outdoors, and report small blisters immediately.
- Hypoglycemia Awareness: Train patients and relatives to recognize early signs like sweating, shaking, and confusion, and keep fast-acting sugar or glucose tablets nearby.