Diabetes mellitus type 2

Overview

•Rising incidence driven by obesity epidemic; peaks during puberty (physiological insulin resistance from growth hormone surges)

•Disproportionately affects South Asian, Black African-Caribbean, and East Asian children

•Mechanism: insulin resistance → compensatory hyperinsulinaemia → beta cell exhaustion → relative insulin deficiency (no autoimmune destruction)

Presentation

•Acanthosis nigricans - velvety, hyperpigmented skin at neck/axillae/groin; marker of hyperinsulinaemia and insulin resistance

•Obesity - present in the majority; calculate BMI centile and waist circumference

•Polyuria and polydipsia - osmotic symptoms from glucosuria

•Recurrent infections - candidal (vulvovaginitis, balanitis), skin infections

•Asymptomatic - frequently identified on opportunistic screening of high-risk individuals

⚠️

T2DM can present with DKA - do not exclude T2DM on the basis of acute presentation alone.

Investigations

•HbA1c - ≥48 mmol/mol confirms diabetes; 42-47 mmol/mol = prediabetes. May be unreliable in haemoglobinopathies or haemolytic anaemia

•Fasting plasma glucose - ≥7.0 mmol/L confirms diabetes; 6.1-6.9 mmol/L = impaired fasting glucose

•Random plasma glucose - ≥11.1 mmol/L with symptoms confirms diabetes

•OGTT (gold standard) - 2-hour glucose ≥11.1 mmol/L confirms diabetes; used when HbA1c or fasting glucose is equivocal

•Diabetes autoantibodies (GAD, IA-2, islet cell) - to exclude T1DM; absence supports T2DM

•Blood ketones - at diagnosis and during intercurrent illness; elevated ketones raise concern for DKA

•Baseline: fasting lipids, urine ACR, eGFR, LFTs, blood pressure

📌

Two separate abnormal results required in the absence of symptoms; one result suffices with unequivocal hyperglycaemic symptoms.

Management

•Refer all children to specialist paediatric diabetes MDT at diagnosis

•Lifestyle intervention - cornerstone; individualised dietary advice from paediatric dietitian, structured physical activity, weight loss advice at every contact

🥇 First-line

•metformin (oral, with meals) - reduces hepatic glucose output and improves insulin sensitivity; titrate slowly to minimise GI side effects

🥈 Second-line

•insulin (basal insulin to start) - add if HbA1c targets not met on metformin alone, or use first-line if severe hyperglycaemia, ketosis, or need for rapid glucose lowering

•Glycaemic target: HbA1c <48 mmol/mol (individualised); SMBG required for children on insulin

🚨

Do NOT stop insulin during intercurrent illness, even if the child is not eating. Illness increases counter-regulatory hormones driving hyperglycaemia and ketogenesis - insulin requirement typically increases. Stopping risks DKA.

Complications

•Microvascular - nephropathy, retinopathy, peripheral neuropathy

•Macrovascular - accelerated atherosclerosis; increased CVD, stroke, peripheral arterial disease risk in early adulthood

•Acute - hypoglycaemia (especially on insulin), DKA, HHS

•Psychosocial - depression, anxiety, disordered eating; bidirectional relationship with glycaemic control

•NAFLD - common comorbidity; monitor liver enzymes

💡

Paediatric-onset T2DM carries an accelerated complication trajectory compared to adult-onset disease due to longer lifetime disease duration and compounding obesity-related cardiovascular risk.

Follow-up and Screening

•HbA1c - every 3 months initially, then at least twice yearly once stable

•Blood pressure - at every clinic visit

•Urine ACR - annually from diagnosis (nephropathy screening)

•Retinal screening - annually; retinopathy can develop within years of diagnosis

•Foot examination and neuropathy assessment - annually

•Fasting lipids - annually; consider statin if dyslipidaemia persists

•Psychosocial assessment - screen for depression, anxiety, eating disorders at every review

Sick-day Rules - When to Escalate

•Seek urgent medical advice if: blood ketones >3 mmol/L; child unable to eat/drink or persistently vomiting >2 hours; dehydration; blood glucose cannot be kept above 3.5 mmol/L; child <3 years old

•Arrange immediate hospital admission if: ketonaemia 1.5-2.9 mmol/L with inability to eat/drink; suspected DKA or HHS; suspected AKI; on insulin with no clinical improvement despite treatment