About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Autoimmune destruction of beta cells — presents with polyuria, polydipsia, weight loss, and fatigue
- Around 25–30% of children present in diabetic ketoacidosis (DKA) — medical emergency
- Diagnosis: random glucose ≥11.1 mmol/L with symptoms, or fasting glucose ≥7.0 mmol/L
- Treatment: lifelong insulin — basal-bolus (MDI) or insulin pump (CSII). Target HbA1c ≤48 mmol/mol (NICE)
- Annual screening for complications from 12 years of age: retinopathy, nephropathy, thyroid disease, coeliac disease
Overview
Type 1 diabetes mellitus (T1DM) is an autoimmune condition in which T-cell-mediated destruction of pancreatic islet beta cells leads to absolute insulin deficiency. It is the most common form of diabetes in children, accounting for over 90% of paediatric diabetes. The condition has a genetic predisposition (HLA-DR3, HLA-DR4) but requires environmental triggers. Without insulin replacement, it is fatal. Modern management with intensive insulin therapy, continuous glucose monitoring (CGM), and insulin pump technology has transformed outcomes.
Epidemiology
T1DM affects approximately 1 in 300–500 children in the UK by age 18. Peak incidence is bimodal: ages 4–6 years and 10–14 years. The UK has one of the highest incidence rates in Europe. Incidence has been increasing by approximately 3–4% per year over recent decades. There is a slight male preponderance in adult-onset T1DM but equal sex distribution in childhood.
Clinical Features
Symptoms
Polyuria — including secondary nocturnal enuresis in a previously dry child
Polydipsia — excessive thirst
Weight loss despite normal or increased appetite
Fatigue and lethargy
Recurrent infections (candidal, skin)
Abdominal pain, nausea, vomiting (DKA)
Kussmaul breathing — deep, sighing respiration (DKA)
Reduced consciousness or confusion (DKA)
Fruity/acetone smell on breath (DKA)
Signs
Dehydration — dry mucous membranes, reduced skin turgor, sunken eyes
Weight loss — may be significant at presentation
Tachycardia
Kussmaul respiration (deep, rapid breathing in DKA)
Altered consciousness (DKA — indicates severe disease)
Hypotension and poor capillary refill (severe DKA)
Investigations
First-line
Random blood glucose≥11.1 mmol/L with symptoms is diagnostic. If asymptomatic, need two abnormal results
Blood or urine ketonesCapillary blood ketones ≥3.0 mmol/L with hyperglycaemia = DKA. Always check at presentation
HbA1cReflects glycaemic control over past 2–3 months. Not used for diagnosis in children. Target ≤48 mmol/mol (NICE)
Second-line
Venous blood gasIf DKA suspected — pH <7.3 and/or bicarbonate <15 mmol/L confirms DKA
Diabetes-specific autoantibodiesGAD, IA-2, ZnT8, IAA — positive in >90% of T1DM. Useful to distinguish from T2DM or monogenic diabetes if clinical picture unclear
C-peptideLow or absent — confirms absolute insulin deficiency (helps distinguish from T2DM)
U&EsAssess dehydration and electrolytes — particularly potassium (may be falsely normal/high in DKA despite total body potassium depletion)
Specialist
Thyroid functionAt diagnosis and annually — autoimmune thyroiditis association (~25% develop thyroid autoantibodies)
Coeliac screen (tTG-IgA + total IgA)At diagnosis and annually for first 3 years, then every 3 years
Retinal screeningAnnual digital retinal photography from age 12
Urine ACRAnnual screening for microalbuminuria from age 12
Management
NICE NG18 — Diabetes (type 1 and type 2) in children and young people & BSPED DKA guidelines1
DKA emergency management (BSPED protocol)
- DKA = glucose >11 mmol/L + pH <7.3 or bicarb <15 + blood ketones ≥3.0
- DO NOT give insulin bolus — risk of cerebral oedema
- Initial fluid resuscitation: 10 mL/kg 0.9% saline bolus ONLY if shocked (max 20 mL/kg)
- IV fluid replacement over 48 hours (calculate deficit + maintenance, max rate determined by BSPED calculator)
- Start IV insulin infusion at 0.05–0.1 units/kg/hour AFTER 1–2 hours of fluids
- Monitor potassium — add KCl once K⁺ <5.5 mmol/L and passing urine
- Hourly blood glucose, 2-hourly blood gas, 4-hourly U&Es
- Cerebral oedema: headache, irritability, reduced GCS → give 2.5 mL/kg 5% hypertonic saline or mannitol
2
Insulin therapy (long-term)
- Basal-bolus MDI (multiple daily injections): long-acting analogue (detemir, glargine, or degludec) + rapid-acting analogue (novorapid, lispro) with meals
- CSII (insulin pump therapy): increasingly offered first-line in UK — continuous subcutaneous insulin infusion
- Hybrid closed-loop systems: automated insulin delivery linked to CGM — increasingly standard of care
- Carbohydrate counting: essential skill — rapid-acting insulin dose calculated from insulin:carb ratio
- Target HbA1c: ≤48 mmol/mol (6.5%) per NICE
3
Monitoring
- Continuous glucose monitoring (CGM) or flash glucose monitoring — offered to all children (NICE)
- Time in range (3.9–10.0 mmol/L) target: >70%
- HbA1c every 3 months
- Regular review with paediatric diabetes MDT: diabetologist, diabetes nurse specialist, dietitian, psychologist
4
Annual review (from age 12)
- HbA1c, thyroid function, coeliac screen
- Retinal screening
- Urine ACR for microalbuminuria
- Blood pressure, BMI, injection/pump site inspection
- Foot assessment in older teenagers
- Mental health screening — diabetes distress, depression, eating disorders (diabulimia)
Complications
- DKA: Life-threatening emergency — cerebral oedema is the most feared complication in children (mortality ~25% if it occurs)
- Hypoglycaemia: Most common acute complication of insulin therapy — educate on recognition and treatment
- Microvascular: Retinopathy, nephropathy, neuropathy — screen annually from age 12
- Macrovascular: Accelerated atherosclerosis — cardiovascular risk management in adolescence
- Psychological: Depression, anxiety, eating disorders (diabulimia — insulin omission for weight loss), diabetes burnout
- Associated autoimmune conditions: Thyroid disease (~25%), coeliac disease (~10%), Addison disease (rare)
UKMLA Exam Tips
- 1Secondary nocturnal enuresis in a previously dry child = always check blood glucose (think T1DM)
- 2DKA: glucose >11, pH <7.3, ketones ≥3.0. Do NOT give insulin bolus in children — risk of cerebral oedema
- 3Cerebral oedema in paediatric DKA: headache → reduced GCS → treat with hypertonic saline or mannitol
- 4Potassium in DKA: may appear normal or high on blood test but total body K⁺ is DEPLETED — always replace once <5.5 and passing urine
- 5HbA1c target ≤48 mmol/mol (NICE). Not used for diagnosis
- 6Screen annually for thyroid disease and coeliac disease from diagnosis
- 7Diabulimia: deliberate insulin omission to lose weight — high DKA and mortality risk, screen at annual review
- 8Honeymoon period: transient improvement in glycaemic control after starting insulin (residual beta cell function) — warn families it will end
practicetest your knowledge on type 1 diabetes in childrenApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — paediatrics and beyond.
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