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PART 1: Urinary Tract Infection (UTI) in Children

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1. Introduction & Epidemiology

• Tintinalli's Emergency Medicine, p. 912

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2. Pathophysiology

• Tintinalli's Emergency Medicine, p. 912

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3. Classification

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4. Risk Factors

• Tintinalli's Emergency Medicine, p. 912

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5. Clinical Symptoms

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6. Diagnosis

Urinalysis

• Pyuria (≥5 WBC/HPF) and bacteriuria are suggestive
• Positive nitrite and/or leukocyte esterase on dipstick supports diagnosis

Urine Culture (Confirmatory)

• Gold standard — must be obtained before starting antibiotics
• Positive = ≥50,000 CFU/mL (updated 2011 AAP threshold, lowered from 100,000)
• Collection method matters: suprapubic aspiration > urethral catheterization > clean-catch midstream (bag specimens are unreliable in infants)

Both an abnormal urinalysis AND a positive culture are required to confirm diagnosis (2011 AAP Guidelines)

Imaging

• Renal-Bladder Ultrasound (RBUS): Performed after first febrile UTI to detect structural anomalies, hydronephrosis, renal scarring
• VCUG (Voiding Cystourethrogram): Recommended if RBUS shows hydronephrosis, scarring, or obstructive uropathy; also after a second febrile UTI
• DMSA Renal Scan: Detects acute pyelonephritis and cortical scarring (most sensitive)

Additional Testing

• Neonates (<2 months): Also obtain blood cultures and lumbar puncture before starting antibiotics (CSF pleocytosis in ~10%; bacterial meningitis in <1%)
• Blood cultures: Routine only in young infants or systemically ill children; ~5–10% of febrile infants with UTI have bacteremia
• Campbell-Walsh Urology, p. 656; Tintinalli's Emergency Medicine, p. 912

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7. Treatment

Antibiotic Treatment by Age (Table 135-5):

Antibiotic Choices:

• First-line: Cephalosporins (e.g., cephalexin, cefdinir, ceftriaxone), trimethoprim-sulfamethoxazole (if locally sensitive), nitrofurantoin (bladder infections only, not for pyelonephritis)
• Note: Many E. coli strains are now resistant to amoxicillin and TMP-SMX — check local sensitivities
• Fluoroquinolones: Only if sensitivities indicate no other option (restricted in children)
• For recurrent UTI or anatomic abnormality: treat per culture/sensitivity results
• Tintinalli's Emergency Medicine, p. 912

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8. Prevention

• Adequate fluid intake and regular voiding
• Proper perineal hygiene (wipe front to back in girls)
• Treatment of constipation and bladder dysfunction
• Circumcision in males reduces risk 4–20×
• Continuous antibiotic prophylaxis (CAP): Previously standard for VUR; now controversial. 2011 AAP guidelines suggest limited benefit in preventing UTI or renal injury from CAP — individualized approach required
• Urologic correction of significant structural abnormalities (VUR grades IV–V, obstructive uropathy)
• Campbell-Walsh Urology, p. 656

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PART 2: Diabetes Mellitus in Children

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1. Overview

• Robbins & Kumar Basic Pathology, p. 743

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2. Classification

• Robbins & Kumar Basic Pathology, p. 744

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3. Pathogenesis

Type 1 DM

• Over 20 susceptibility loci identified by GWAS
• Strongest association: Class II MHC (HLA-DR3 and/or DR4) — present in 90–95% of European T1DM patients vs. ~40% of unaffected individuals
• DR3/DR4 heterozygotes: 40–50% of T1DM patients vs. 5% of unaffected
• Non-HLA susceptibility genes: Insulin gene polymorphisms (reduced thymic expression → failure to eliminate self-reactive T cells), CTLA-4, PTPN22 (both inhibit T-cell responses — loss-of-function → excessive T-cell activation)

• Failure of self-tolerance in CD4+ and CD8+ T cells specific for β-cell antigens
• Destruction mediated primarily by T cells (Type IV/cell-mediated hypersensitivity)
• Pancreatic histology shows insulitis — lymphocytic infiltration and β-cell necrosis
• Autoantibodies (markers, not necessarily causative) present in 70–80%: islet cell autoantibodies (ICA), anti-insulin (IAA), anti-GAD65, anti-IA-2, anti-IA-2β

• Viral infections (Coxsackievirus B, enteroviruses) may trigger or accelerate autoimmunity
• Gut microbiome changes implicated
• Concordance in monozygotic twins <100% — confirming environmental contribution

• Robbins & Kumar Basic Pathology, p. 744–745; Mulholland & Greenfield's Surgery, p. 1889

Type 2 DM in Children

• Driven primarily by obesity and insulin resistance
• Initially: β-cell hypersecretion compensates for resistance → hyperinsulinemia
• Eventually: β-cell exhaustion and apoptosis (mediated by glucotoxicity, lipotoxicity, cytokines)
• Obesity, sedentary lifestyle, family history, and ethnicity are key drivers

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4. Risk Factors

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5. Clinical Symptoms

Classic "3 Polys" Triad:

• Polyuria — osmotic diuresis from glucosuria
• Polydipsia — compensatory response to fluid loss
• Polyphagia — cellular starvation despite hyperglycemia

Additional Symptoms:

• Weight loss — catabolism of fat and muscle
• Fatigue and weakness
• Blurred vision — osmotic changes in the lens
• Enuresis (new-onset bedwetting in previously continent child)
• Recurrent infections (skin, UTI, candidiasis)

Diabetic Ketoacidosis (DKA) — Acute Presentation in Children:

• Vomiting, abdominal pain, Kussmaul breathing (deep, rapid)
• Fruity (acetone) breath
• Dehydration, altered consciousness
• Can be the first presentation of T1DM in children
• Biochemical hallmarks: hyperglycemia, metabolic acidosis, ketonemia/ketonuria

Type 2 DM in Children (often insidious):

• May be asymptomatic at diagnosis
• Acanthosis nigricans (dark velvety skin folds — marker of insulin resistance)
• Obesity, hypertension, dyslipidemia

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6. Diagnosis

Diagnostic Criteria (ADA/WHO):

• All tests except random glucose with classic symptoms must be confirmed on a separate day
• Acute stress hyperglycemia (infection, trauma) must resolve before confirming diagnosis
• Robbins & Kumar Basic Pathology, p. 743

Differentiating T1DM from T2DM in Children:

Additional Tests:

• C-peptide — measures residual β-cell function
• HbA1c — reflects 3-month glycemic control
• Anti-GAD65, anti-IA-2, anti-insulin antibodies — confirm autoimmune T1DM
• Screen for comorbidities: Thyroid peroxidase antibodies, tissue transglutaminase (celiac), 21-hydroxylase antibodies (Addison's)
• Lipid panel, renal function, blood pressure monitoring
• Textbook of Family Medicine, p. 985

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7. Treatment

Type 1 DM in Children

• Basal-bolus (MDI — Multiple Daily Injections): Long-acting basal + rapid-acting with each meal (preferred for flexibility)
• CSII (Insulin Pump): Continuous subcutaneous insulin infusion; preferred in young children
• Sensor-augmented pump / AID (Automated Insulin Delivery): CGM + pump + algorithm adjusts insulin automatically in real-time — the gold standard in modern pediatric diabetes care
• Total Daily Dose (TDD) ≈ 0.7 units/kg/day (50% basal, 50% bolus)

• Self-monitoring of blood glucose (SMBG) before meals and at bedtime
• Continuous Glucose Monitor (CGM) — real-time, reduces hypoglycemia risk
• Target glucose: Fasting 90–130 mg/dL; 2-hour postprandial <180 mg/dL
• HbA1c target: <7% in most children (individualized)

Type 2 DM in Children

• Lifestyle modification first: Diet, physical activity, weight management
• Metformin: First-line pharmacotherapy (improves insulin sensitivity)
• Insulin: If HbA1c very high, symptomatic, or metformin fails
• Newer agents (GLP-1 agonists, SGLT2 inhibitors) under investigation in pediatric populations

DKA Management (emergency):

• IV fluid resuscitation
• Insulin infusion (regular insulin IV)
• Electrolyte correction (especially potassium)
• Monitoring for cerebral edema (major pediatric DKA complication)

Education & Psychosocial Support:

• Certified diabetes educators, dietitian counseling
• Carbohydrate counting and insulin-to-carb ratio
• School management plans, psychological support (depression/anxiety prevalent)
• Self-management education improves HbA1c outcomes (Meta-Analysis: PMID 40302946)

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8. Prevention

Type 1 DM:

• No proven primary prevention strategy exists currently
• Teplizumab (monoclonal antibody targeting CD3/CD8+ T cells): Delays progression from Stage 2 (autoantibody-positive) to clinical T1DM by a median of ~2 years — FDA-approved (2022) for high-risk individuals
• Trials with nasal insulin and oral insulin for immune modulation — not conclusively effective
• Genetic + autoantibody screening of high-risk relatives (first-degree relatives) allows early identification; presence of ≥2 autoantibodies → 75% risk of T1DM within 10 years
• Mulholland & Greenfield's Surgery, p. 1889

Type 2 DM:

• Primary prevention through combating obesity: healthy diet, regular physical activity, limiting screen time
• Breastfeeding in infancy reduces later obesity risk
• Community-based programs targeting high-risk populations (Hispanic, African American, Native American youth)
• Treatment of prediabetes (IFG/IGT) with lifestyle change reduces progression to T2DM

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Recent Evidence (PubMed)

• ACR Appropriateness Criteria for Pediatric UTI (2024 Update) — updated imaging algorithms for febrile UTI (PMID 38823954)
• WikiGuidelines Consensus on UTI in Pediatrics & Adults (2024, JAMA Network Open) — comprehensive prevention, diagnosis, and management guidelines (PMID 39495518)

• Incidence of diabetes in children during COVID-19: Systematic Review & Meta-Analysis (2023, JAMA Network Open) — significant rise in new-onset T1DM incidence during/after COVID-19 pandemic (PMID 37389869)
• Educational self-management interventions in children with T1DM: Meta-Analysis (2024) — structured self-management education significantly improves glycemic control (PMID 40302946)
• Hypoglycemia recognition and management in pediatric diabetes: Systematic Review (2024) — evidence-based recommendations for recognizing and treating hypoglycemia in children (PMID 38894740)

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Summary Table

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