Incidental Glucosuria in Children

Essentials

• Detect possible insulin-dependent diabetes mellitus as the cause of incidental glucosuria and arrange for care urgently.
• If diabetes is not the cause of glucosuria, refer the patient non-urgently to a pediatric clinic.

Causes

• Blood glucose is elevated because of diabetes or some other cause
  • About 6% of children with asymptomatic glucosuria later develop type 1 diabetes.
• Stress factors
  • Infections (and e.g. glucocorticoid medication in the treatment of asthma or laryngitis)
  • Traumas
  • Burn injuries
  • Hypoxia
  • Hypothermia
  • Surgery
• Low renal threshold
  • E.g. mutation in the SLC5A2 gene causes excretion of glucose into the urine already at glucose concentrations of about 5 mmol/l.
• Hyponatraemic dehydration caused by diarrhoea
• Certain medications can cause glucosuria in high doses
  • Cephalosporins
  • Penicillin G
  • Nitrofurantoin
  • Anti-inflammatory agents (glucocorticoids, NSAID drugs)
  • Ascorbic acid

Investigation strategy in cases of symptomless glucosuria

1. Determine blood glucose concentration immediately
   • If the fasting level is examined and the plasma level exceeds 7.0 mmol/l or postprandial level exceeds 11.1 mmol/l (in venous blood 6.7 or 10 mmol/l respectively) diabetes is probable and the child should be referred urgently to further investigations (oral glucose tolerance) and treatment.
   • If only postprandial glucose levels can be examined and the result (plasma glucose) is below 11.1 mmol/l and the child is asymptomatic, the fasting value should be examined on the next morning. If the level is above 7.0 mmol/l, action is taken as instructed above. In unclear cases always consult an on call pediatric clinic.
2. If blood glucose level is < 6.7 mmol/l, further investigations can be performed in primary care.
   • A control urine sample on the next morning or at the latest when a known stress factor, for example, infection has disappeared.
   • Glycosylated haemoglobin determination
     • If HbA_1c concentration is increased but fasting glucose concentration is normal, the child is referred to specialized care on the next day.
   • Antibodies against pancreatic islet cells and other autoantibodies associated with type 1 diabetes are only determined in specialized care (IA2A, ZnT8, GAD and insulin autoantibodies).
3. If the results of these investigations are normal and there is no diabetes in the family, further investigations are not necessary and follow-up is not needed.
4. Further investigations are indicated
   • immediately if
     • glucosuria is detected repeatedly
     • HbA_1c exceeds reference values
   • within 2-3 weeks if a family member has type 1 diabetes.
5. Further investigations should be performed in a paediatric specialist unit
   • The parents follow whether the child develops symptoms of diabetes (excessive drinking, frequent urination, fatigue) and, if needed, check the blood glucose level, examine whether there is glucose in the urine and contact the paediatric unit.