66 Diabetes Mellitus
66.1 Introduction
Diabetes mellitus (DM) is a chronic metabolic disorder characterized by persistent hyperglycaemia resulting from defects in insulin secretion, insulin action, or both.
In children, diabetes is one of the most common endocrine and metabolic disorders encountered in clinical practice. The two main types seen are Type 1 diabetes mellitus (T1DM) and Type 2 diabetes mellitus (T2DM), though other rare forms such as monogenic diabetes and secondary diabetes also occur.
In Ghana and many parts of sub-Saharan Africa, the incidence of Type 1 diabetes is increasing, with children presenting frequently in diabetic ketoacidosis (DKA). In recent years, Type 2 diabetes has emerged among adolescents due to rising rates of obesity and sedentary lifestyles.
This chapter provides a detailed overview of diabetes mellitus in children — covering definitions, classification, pathophysiology, clinical features, diagnosis, management, and complications — with special emphasis on practical approaches for medical students and paediatric residents.
66.2 Classification of Diabetes Mellitus
The American Diabetes Association (ADA) and World Health Organization (WHO) classify diabetes as follows:
| Category | Description | Pathophysiology |
|---|---|---|
| Type 1 Diabetes Mellitus (T1DM) | Autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency | Immune-mediated; often associated with islet autoantibodies |
| Type 2 Diabetes Mellitus (T2DM) | Combination of insulin resistance and relative insulin deficiency | Associated with obesity, puberty, and family history |
| Monogenic Diabetes (MODY/Neonatal DM) | Single-gene defects affecting β-cell function | Often autosomal dominant inheritance |
| Secondary Diabetes | Secondary to other conditions | Pancreatitis, cystic fibrosis, steroid therapy, endocrine disorders |
66.3 Epidemiology
- Global trends: T1DM accounts for over 90% of diabetes in children globally. The incidence varies widely, from <1/100,000 in sub-Saharan Africa to >30/100,000 in Europe.
- In Ghana: Studies in Kumasi, Accra, and Cape Coast indicate increasing T1DM cases among children aged 5–15 years, often presenting with DKA at diagnosis.
- Type 2 diabetes: Previously rare, it is now reported among Ghanaian adolescents, especially those with obesity and a strong family history.
The rise in diabetes prevalence among children is attributed to improved awareness, urbanization, lifestyle changes, and possibly environmental triggers.
66.4 Physiology of Insulin and Glucose Homeostasis
The pancreas plays a central role in glucose metabolism.
The β-cells of the islets of Langerhans secrete insulin, a peptide hormone that facilitates glucose uptake by muscle and adipose tissue and suppresses hepatic glucose production.
66.4.1 Key Actions of Insulin
- Increases glucose uptake via GLUT-4 transporters.
- Promotes glycogen synthesis in liver and muscle.
- Inhibits gluconeogenesis and glycogenolysis.
- Enhances lipid and protein synthesis.
Deficiency or resistance to insulin leads to hyperglycaemia, lipolysis, ketogenesis, and protein catabolism, which underlie the metabolic disturbances seen in diabetes.
66.5 Pathophysiology
66.5.1 Type 1 Diabetes Mellitus (T1DM)
An autoimmune process targets pancreatic β-cells, resulting in progressive loss of insulin production.
66.5.1.1 Mechanism
- Genetic predisposition (HLA-DR3, DR4, DQ2, DQ8).
- Environmental triggers (viral infections—Coxsackie B, enterovirus, or toxins).
- Presence of autoantibodies: GAD65, ICA, IA-2, or ZnT8.
Destruction of >80% of β-cells leads to insulin deficiency, hyperglycaemia, and ketone formation.
66.5.1.2 Natural History
- Genetic predisposition
- Autoimmunity initiation
- Progressive β-cell destruction
- Clinical diabetes (symptomatic hyperglycaemia or DKA)
66.5.2 Type 2 Diabetes Mellitus (T2DM)
Characterized by insulin resistance and relative insulin deficiency.
- Strongly linked to obesity, acanthosis nigricans, and family history.
- Insulin resistance is worsened by puberty hormones, sedentary lifestyle, and high-calorie diets.
66.5.3 Other Forms
- Monogenic diabetes: Often presents in infancy or early childhood; may respond to sulfonylureas rather than insulin.
- Secondary diabetes: Can follow steroid therapy, Cushing syndrome, or pancreatitis.
66.6 Clinical Features
The presentation of diabetes in children depends on its type and stage at diagnosis.
66.6.1 Classical Symptoms of Type 1 Diabetes
- Polyuria – due to osmotic diuresis.
- Polydipsia – compensatory thirst.
- Polyphagia – despite weight loss.
- Weight loss and fatigue – from catabolism.
- Enuresis or nocturia – previously toilet-trained child.
- Recurrent infections – especially skin and vulvovaginal candidiasis.
In many Ghanaian children, the disease is recognized late, often presenting as diabetic ketoacidosis (DKA) with vomiting, abdominal pain, and dehydration.
66.6.2 Features of Type 2 Diabetes
- Often asymptomatic or mildly symptomatic.
- Associated with obesity, acanthosis nigricans, hypertension, or dyslipidaemia.
- May also present with ketosis (ketosis-prone T2DM).
66.7 Diabetic Ketoacidosis (DKA)
DKA is the most serious acute complication of diabetes in children and remains a major cause of morbidity and mortality in Ghana.
66.7.1 Pathophysiology
Absolute or relative insulin deficiency → increased lipolysis → free fatty acids converted to ketone bodies (acetoacetate, β-hydroxybutyrate) → metabolic acidosis.
66.7.2 Diagnostic Criteria (WHO/ISPAD)
- Blood glucose >11 mmol/L
- Venous pH <7.3 or bicarbonate <15 mmol/L
- Presence of ketonaemia or ketonuria
66.7.3 Clinical Features
- Dehydration
- Kussmaul breathing (deep, laboured)
- Fruity (acetone) breath
- Abdominal pain, vomiting
- Drowsiness or altered consciousness
66.7.4 Complications
- Cerebral oedema (most feared, especially in children)
- Shock and electrolyte imbalance
66.7.5 Management Principles
- Fluid resuscitation: 0.9% saline initially, then adjusted.
- Insulin therapy: IV infusion 0.05–0.1 U/kg/hr after initial fluid resuscitation.
- Electrolyte correction: especially potassium.
- Treatment of precipitating cause: infection, missed insulin dose, etc.
- Close monitoring: vital signs, glucose, electrolytes, and neurological status.
66.8 Diagnostic Evaluation
66.8.1 Diagnostic Criteria for Diabetes (WHO)
| Test | Diagnostic Value |
|---|---|
| Fasting plasma glucose | ≥7.0 mmol/L (after ≥8 hours fasting) |
| Random plasma glucose | ≥11.1 mmol/L with symptoms |
| 2-hour OGTT plasma glucose | ≥11.1 mmol/L |
| HbA1c | ≥6.5% (in standardized lab) |
In children, diagnosis is typically based on random glucose and clinical presentation, especially when symptomatic.
66.8.2 Additional Laboratory Tests
- Urine dipstick for glucose and ketones
- Serum electrolytes, urea, creatinine
- Blood gas for acidosis (if DKA suspected)
- HbA1c for baseline control
- Autoantibody screening (GAD, ICA) when available
- Lipid profile (for T2DM)
66.9 Differential Diagnosis of Polyuria and Polydipsia
| Condition | Key Features |
|---|---|
| Diabetes mellitus | Hyperglycaemia, glucosuria, ketonuria |
| Diabetes insipidus | Dilute urine, normal glucose |
| Psychogenic polydipsia | Normal glucose, no ketones |
| Chronic renal disease | Proteinuria, elevated creatinine |
66.10 Management of Type 1 Diabetes Mellitus
The cornerstone of management is lifelong insulin therapy with education, diet regulation, and psychosocial support.
66.10.1 Insulin Therapy
66.10.1.1 Types of Insulin
| Type | Onset | Peak | Duration |
|---|---|---|---|
| Rapid-acting (Lispro, Aspart) | 10–15 min | 1–2 hr | 3–5 hr |
| Short-acting (Regular) | 30–60 min | 2–4 hr | 6–8 hr |
| Intermediate (NPH) | 2–4 hr | 6–10 hr | 12–18 hr |
| Long-acting (Glargine, Detemir) | 1–2 hr | Minimal | 24 hr |
66.10.1.2 Insulin Regimens
- Conventional: Two daily injections (mixed short- and intermediate-acting).
- Basal–bolus: Long-acting basal + rapid-acting at meals.
- Insulin pump therapy: Rarely available in Ghana but ideal for motivated families.
66.10.1.3 Dose
- Starting total daily dose: 0.5–1.0 units/kg/day.
- Adjust according to blood glucose trends.
66.10.1.4 Monitoring
- Self-monitoring of blood glucose (SMBG): before meals and at bedtime.
- HbA1c: every 3–6 months; target <7.5%.
- Growth and pubertal assessment at each visit.
66.10.2 Nutritional Management
Dietary management aims at maintaining normoglycaemia while ensuring adequate growth.
66.10.2.1 Principles
- Balanced diet with appropriate carbohydrate distribution (50–55% of calories).
- Encourage high-fibre complex carbohydrates; limit refined sugars.
- Consistent meal timing, coordinated with insulin action.
- Carbohydrate counting for insulin adjustment.
- Avoid fasting or skipping meals.
In Ghana, diets can incorporate local foods — e.g., whole grain banku, kontomire stew, beans, plantain — with attention to portion control and reduced oil.
66.10.3 Exercise
Regular physical activity improves insulin sensitivity and cardiovascular health.
Precautions: - Monitor glucose before and after exercise.
- Take extra carbohydrates if prolonged activity (>60 min).
- Avoid vigorous exercise if glucose >14 mmol/L with ketones.
66.11 Management of Type 2 Diabetes Mellitus
Management begins with lifestyle modification, followed by pharmacotherapy if control is inadequate.
66.11.1 Lifestyle Modification
- Weight reduction through diet and exercise.
- Reduction of sugary beverages and fried foods.
- Screen family members for diabetes and obesity.
66.11.2 Pharmacological Treatment
- Metformin is the first-line agent (500 mg once or twice daily, titrated as tolerated).
- Insulin may be required temporarily if hyperglycaemia is severe or during intercurrent illness.
- Blood pressure and lipid control are also essential.
66.12 Acute and Chronic Complications
66.12.1 Acute Complications
| Complication | Description | Prevention |
|---|---|---|
| Hypoglycaemia | Glucose <3.9 mmol/L due to excess insulin or missed meals | Regular meals, dose adjustment, carry glucose snacks |
| Diabetic Ketoacidosis (DKA) | Life-threatening metabolic acidosis | Early recognition and adherence |
| Infections | Urinary tract, skin, respiratory | Good hygiene, immunizations |
66.12.2 Chronic Complications
These are rare in well-controlled paediatric patients but may develop after years of poor control.
| System | Complication | Screening |
|---|---|---|
| Eyes | Retinopathy | Fundoscopy from 11 years or 2 years post-diagnosis |
| Kidneys | Microalbuminuria → nephropathy | Annual urine albumin/creatinine ratio |
| Nerves | Peripheral neuropathy | Clinical exam annually |
| Cardiovascular | Hypertension, dyslipidaemia | BP check, lipid profile |
Prevention lies in good glycaemic control (HbA1c <7.5%), healthy lifestyle, and regular follow-up.
66.13 Follow-Up and Long-Term Care
66.13.1 Key Components
- Growth and pubertal monitoring.
- Annual screening for complications.
- Psychosocial evaluation.
- Immunizations: influenza, pneumococcal, hepatitis B.
- Transition planning from paediatric to adult diabetes care.
66.13.2 School Support
- Teachers and school nurses should understand the child’s condition.
- Allow glucose monitoring and snacks when needed.
- Create an emergency plan for hypoglycaemia.
66.14 Special Considerations in Ghana
- Late presentation due to limited awareness and poor access to diagnostic tools.
- Insulin affordability remains a challenge; reliance on hospital pharmacies or NHIS coverage is common.
- Refrigeration issues in rural areas affect insulin storage; traditional clay pot coolers may help.
- Cultural beliefs sometimes lead to trial of herbal remedies, delaying therapy.
- Education of healthcare workers at peripheral centres is vital to improve early diagnosis and management.
66.15 Emerging Trends
- Use of continuous glucose monitoring (CGM) and insulin pens is increasing in urban Ghana.
- Tele-diabetes follow-up and community-based screening programmes are expanding.
- Research into autoantibody prevalence and genetic profiles in African children with diabetes is ongoing.
66.16 Summary Table
| Type | Mechanism | Key Features | Management |
|---|---|---|---|
| Type 1 | Autoimmune β-cell destruction → insulin deficiency | Polyuria, weight loss, DKA | Insulin + diet + education |
| Type 2 | Insulin resistance + relative deficiency | Obesity, acanthosis nigricans | Lifestyle + metformin ± insulin |
| Monogenic | Single gene mutation | Neonatal/childhood onset, family history | May respond to sulfonylureas |
| Secondary | Due to other diseases/drugs | Variable | Treat underlying cause |
66.17 Key Takeaways
- Diabetes mellitus is an increasingly common chronic condition in Ghanaian children.
- Type 1 diabetes remains predominant, with DKA as the main presenting feature.
- Insulin therapy, dietary regulation, and education are the cornerstones of management.
- Early recognition, regular follow-up, and psychosocial support significantly reduce morbidity.
- Improving awareness and healthcare access remain critical to improving outcomes.
66.18 Suggested Reading
- International Society for Pediatric and Adolescent Diabetes (ISPAD) Clinical Practice Guidelines, 2022.
- Nelson Textbook of Pediatrics, 22nd Edition.
- WHO Pocket Book of Hospital Care for Children, 3rd Edition.
- Ghana Health Service (GHS) Clinical Guidelines, 2024 Edition.
- Amissah-Arthur MB, et al. “Profile of childhood diabetes mellitus at Komfo Anokye Teaching Hospital, Kumasi.” Ghana Medical Journal 2020.