What is the diagnosis and treatment plan for a pediatric patient presenting with polyuria, polydipsia, and polyphagia, with a blood glucose level of hyperglycemia?

Diagnosis and Management of New-Onset Type 1 Diabetes in a 10-Year-Old

This 10-year-old presenting with polyuria, polydipsia, polyphagia, and a blood glucose of 345 mg/dL has new-onset Type 1 diabetes and requires immediate insulin therapy without delay. 1

Immediate Diagnostic Workup

Order these tests immediately:

• Urine dipstick for glycosuria and ketonuria (mandatory test) 1
• HbA1c to assess duration of hyperglycemia 1
• Serum or urine ketones (blood β-hydroxybutyrate preferred in young children as it allows earlier detection) 2
• Basic metabolic panel to assess for diabetic ketoacidosis (DKA) and electrolyte abnormalities 2
• Islet autoantibodies (GAD65, IA-2, insulin autoantibodies, ZnT8) to confirm autoimmune Type 1 diabetes 2, 3

The combination of classic symptoms (polyuria, polydipsia, polyphagia) plus random plasma glucose ≥200 mg/dL is sufficient to diagnose diabetes without delay—no need to wait for confirmatory testing before starting treatment 1. At 345 mg/dL with classic symptoms, this child meets diagnostic criteria immediately 2.

Classification: Type 1 vs Type 2 Diabetes

This presentation strongly suggests Type 1 diabetes based on:

• Age 10 years with classic triad of symptoms 2
• Acute onset with marked hyperglycemia 2
• Presence of polyphagia (distinguishes from other causes of polyuria) 1

Children with Type 1 diabetes typically present with polyuria/polydipsia, and approximately half present with DKA 2. While Type 2 diabetes is increasing in children, it typically occurs in obese adolescents (BMI ≥85th percentile) with strong family history, and most are over 10 years old in middle-to-late puberty 2. The presence of polyphagia rather than weight loss, and the acute presentation, make Type 1 diabetes most likely 2.

Immediate Treatment Protocol

Start insulin therapy immediately—do not delay 1:

Initial Insulin Regimen

Basal insulin (long-acting glargine or detemir):

• Starting dose: 0.5 units/kg/day administered once daily at bedtime 1
• For a typical 10-year-old weighing ~30-35 kg, this equals approximately 15-18 units at bedtime 4

Prandial insulin (rapid-acting: lispro, aspart, or glulisine):

• Starting dose: 4-6 units before each main meal 1
• Alternatively, calculate as 50% of total daily insulin dose divided among three meals 1
• Teach carbohydrate counting for dose adjustments (consistency more important than accuracy initially) 2

Critical Decision Points

If the child has any of the following, hospitalize immediately:

• Ketones present (blood β-hydroxybutyrate >0.6 mmol/L or moderate-to-large urine ketones) 2
• Signs of DKA (acidosis, vomiting, altered mental status) 2
• Blood glucose ≥250 mg/dL with symptoms 2, 1
• HbA1c >9% 1

If metabolically stable (no ketones, glucose <250 mg/dL, asymptomatic except for polyuria/polydipsia):

• Can initiate outpatient insulin therapy with close follow-up 2
• However, given glucose of 345 mg/dL, strongly consider brief hospitalization for diabetes education and metabolic stabilization 1

Monitoring Requirements

Blood glucose monitoring:

• Check fasting glucose daily 1
• Check pre-meal and 2-hour post-meal glucose at least 3-4 times daily initially 1
• Target pre-meal glucose: 90-130 mg/dL 2
• Target bedtime glucose: 90-150 mg/dL 2

HbA1c monitoring:

• Measure every 3 months 2, 1
• Target HbA1c: <7.0% (53 mmol/mol) for most children and adolescents 2, 1
• More stringent target of <6.5% acceptable if achieved without significant hypoglycemia 2

Consider continuous glucose monitoring (CGM) as it improves glycemic control and reduces hypoglycemia risk in pediatric Type 1 diabetes 2

Follow-Up Schedule

Within 24-48 hours:

• Review blood glucose logs 1
• Assess for hypoglycemia symptoms and ketone monitoring technique 2
• Reinforce insulin administration technique 2

Within 1 week:

• Comprehensive diabetes education session with certified diabetes educator 2
• Adjust insulin doses based on glucose patterns (typically increase by 10-20% if targets not met) 1
• Establish sick-day management plan 2

Within 2-4 weeks:

• Endocrinology referral for ongoing management 2
• Assess family coping and psychosocial adjustment 2

Every 3 months:

• HbA1c measurement 2, 1
• Review glucose logs and adjust insulin regimen 1
• Screen for complications (annual screening for retinopathy, nephropathy after 5 years duration or at puberty) 2

Critical Pitfalls to Avoid

Never delay insulin initiation in a child with marked hyperglycemia and classic symptoms—this can lead to rapid metabolic decompensation and DKA 1. The blood glucose of 345 mg/dL requires immediate insulin therapy 1.

Do not assume Type 2 diabetes without checking islet autoantibodies, as misclassification leads to inappropriate treatment 2. While Type 2 is increasing in children, the acute presentation with polyphagia strongly suggests Type 1 2.

Ensure developmentally appropriate family involvement—premature transfer of diabetes care to a 10-year-old results in poor self-management and deteriorating glycemic control 2. Parents must remain actively involved in all insulin dosing decisions at this age 2.

Monitor for hypoglycemia closely during initial insulin titration, especially overnight and with physical activity 2. Teach family to recognize and treat hypoglycemia with 15 grams of fast-acting carbohydrate 2.

Check ketones during any illness or when blood glucose >250 mg/dL—failure to detect ketones early can lead to DKA 2, 1. Blood ketone monitoring (β-hydroxybutyrate) is preferred in young children who cannot urinate on demand 2.