Diabetes in Children — Type 1, Type 2, Causes, Insulin & Management Guide — Symptoms, Causes & Treatment | MyMedicPlus

Diabetes mellitus in children encompasses Type 1 diabetes (T1D) — the most common form in childhood — and increasingly Type 2 diabetes (T2D) in overweight adolescents. T1D is a chronic autoimmune condition in which the immune system destroys insulin-producing beta cells in the pancreatic islets of Langerhans, resulting in absolute insulin deficiency. Without insulin, glucose cannot enter cells for energy, accumulates in the blood, and triggers a life-threatening metabolic crisis (diabetic ketoacidosis, DKA) if untreated. Over 1.2 million children and adolescents have T1D globally, with incidence rising 3-4% per year. T1D typically presents acutely over days to weeks, often in children aged 5-14 years, though it can present at any age. T2D in children, once rare, is now increasing in parallel with the childhood obesity epidemic — characterised by insulin resistance rather than deficiency, typically in overweight adolescents from ethnic minority groups.

Type 1 diabetes: T1D results from T-cell-mediated autoimmune destruction of beta cells in genetically susceptible individuals. HLA class II gene variants (particularly HLA-DR3-DQ2 and HLA-DR4-DQ8 haplotypes) confer the greatest genetic risk — present in 90% of T1D patients. Concordance in identical twins is only 40-50%, indicating environmental triggers are essential. Environmental factors implicated: enteroviruses (particularly Coxsackievirus B); gut microbiome dysbiosis in early infancy; reduced exposure to infectious agents in early childhood ('hygiene hypothesis'); early introduction of cow's milk protein; and vitamin D deficiency. Islet autoantibodies (GAD65, ZnT8, IA-2, insulin autoantibodies) appear years before clinical onset, offering a window for prediction. Type 2 diabetes risk factors in children: obesity (central adiposity), family history of T2D, South Asian, Black African/Caribbean, or Hispanic ethnicity, polycystic ovary syndrome (PCOS) in adolescent girls, and intrauterine exposure to gestational diabetes.

The classic presenting triad of T1D in children: polydipsia (excessive thirst — drinking abnormally large volumes), polyuria (passing large amounts of urine frequently, nocturia or bed-wetting in a previously dry child), and weight loss despite increased appetite (polyphagia). Fatigue and lethargy are common. Symptoms typically develop over 1-6 weeks. Diabetic ketoacidosis (DKA — occurring in 25-40% of children at first presentation): abdominal pain, nausea and vomiting, sweet or fruity ('acetone') breath, rapid deep breathing (Kussmaul respiration — compensation for metabolic acidosis), confusion, dehydration, and ultimately coma. DKA is a medical emergency with significant mortality risk if not treated promptly in a paediatric intensive care setting. Type 2 diabetes in adolescents often presents insidiously or asymptomatically, detected on screening; acanthosis nigricans (velvety darkening of skin folds at neck, axillae — a marker of insulin resistance) and hypertension may be present.

Diagnosis of diabetes in children: random plasma glucose above 11.1 mmol/L (200 mg/dL) with symptoms, or fasting plasma glucose above 7.0 mmol/L (126 mg/dL), or HbA1c above 48 mmol/mol (6.5%) on two occasions. In symptomatic children with obvious hyperglycaemia, a single diagnostic test is sufficient. DKA diagnosis: blood glucose above 11 mmol/L, pH below 7.3 or bicarbonate below 15 mmol/L, and ketonaemia (blood ketones above 3 mmol/L) or ketonuria. Distinguishing T1D from T2D in children: islet autoantibodies (GAD65, ZnT8, IA-2 antibodies — positive in 90% of T1D); C-peptide (low/undetectable in T1D, elevated in T2D indicating residual insulin production); and clinical features. MODY (monogenic diabetes) should be suspected in slender children with a strong family history of diabetes — genetic testing identifies specific mutations (HNF1A, GCK, HNF4A).

Type 1 diabetes requires lifelong insulin replacement — no oral agents are approved as standalone treatment. Basal-bolus regimen: multiple daily injections (MDI) — long-acting insulin once or twice daily (glargine, detemir, degludec) providing background insulin coverage, plus rapid-acting insulin (lispro, aspart, glulisine) with each meal calculated on carbohydrate counting (insulin-to-carbohydrate ratio). Continuous subcutaneous insulin infusion (CSII/insulin pump): delivers continuous basal insulin with boluses at meals; preferred in young children and those with frequent hypoglycaemia or high HbA1c. Closed-loop systems (artificial pancreas — e.g., Omnipod 5, MiniMed 780G): automatically adjust insulin based on continuous glucose monitoring (CGM) readings using an algorithm. CGM (Dexterity G7, Libre 3, Medtronic) replaces finger-prick testing — provides real-time glucose, trends, and alarms; dramatically reduces hypoglycaemia and improves HbA1c. Target HbA1c in children: below 48 mmol/mol (6.5%) is ideal, with below 53 mmol/mol (7.0%) as the pragmatic target, balancing tight control against hypoglycaemia risk. Type 2 diabetes in children: lifestyle intervention (structured diet and exercise) plus metformin as first-line; insulin if poorly controlled.

Diabetic ketoacidosis (DKA) is the most acute life-threatening complication of T1D in children — occurring in 25-40% at initial diagnosis and during intercurrent illnesses. Cerebral oedema complicates 0.5-1% of paediatric DKA episodes and carries 20-25% mortality. Long-term hyperglycaemia causes microvascular complications beginning 5-10 years after diagnosis: diabetic retinopathy (leading cause of blindness in working-age adults), nephropathy (progressive kidney disease leading to dialysis), and peripheral neuropathy. The DCCT trial demonstrated that intensive glycaemic control reduces microvascular complication risk by 50-75%. Recurrent severe hypoglycaemia from insulin overdose causes cognitive impairment, seizures, cardiac arrhythmias, and acute brain injury. Psychological comorbidities — diabetes burnout, anxiety, and depression — significantly impair self-management in adolescents.

Type 1 diabetes cannot currently be prevented, though clinical trials of antigen-specific immunotherapy and teplizumab (anti-CD3 antibody) have shown delay in clinical onset in very high-risk individuals. Teplizumab is FDA-approved (2022) for delaying T1D onset in Stage 2 (autoantibody-positive, dysglycaemic) relatives of T1D patients. Type 2 diabetes in children is preventable through addressing childhood obesity: promoting healthy diet, limiting ultra-processed food and sugar-sweetened beverages, and ensuring 60 minutes of moderate-vigorous physical activity daily. For all children with diabetes: structured diabetes education for the child and family (carbohydrate counting, sick day rules, hypoglycaemia recognition and treatment); psychological support; school care plans; and regular review by a multidisciplinary team including paediatric diabetologist, diabetes specialist nurse, dietitian, and psychologist.

Seek emergency care immediately if your child has: fruity or acetone-smelling breath; deep rapid breathing; vomiting that prevents eating; confusion or drowsiness; or blood ketones above 3 mmol/L — these indicate diabetic ketoacidosis, a life-threatening emergency. Call emergency services or go directly to a paediatric emergency department. For newly presenting diabetes: any child with excessive thirst, frequent urination, unexplained weight loss, or bed-wetting after a period of dryness should be assessed by a GP urgently — a blood or urine glucose test can confirm or exclude diabetes same day. For established T1D: contact your diabetes team if blood glucose is persistently above 15 mmol/L despite correction doses, if ketones are rising, if the child is unwell and unable to keep fluids down, or if hypoglycaemia is occurring frequently.