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Urinary Tract Infection (UTI) in Children — Introduction

Urinary tract infection (UTI) (outlink to CDC) is one of the most common serious bacterial infections in childhood and an important cause of fever, morbidity, and potential long-term renal damage. UTIs involve infection of the urinary system, including the bladder (cystitis) and kidneys (pyelonephritis). Early recognition and appropriate management are essential to prevent complications such as renal scarring, hypertension, and chronic kidney disease.

Epidemiology

UTIs occur in approximately 5–8% of girls and 1–2% of boys by 7 years of age. During infancy, UTIs are more common in boys, especially those who are uncircumcised. After the first year of life, girls are affected more frequently due to anatomical and behavioral factors.

Causative Agents

The most common causative organism is Escherichia coli, accounting for the majority of infections. Other pathogens include Klebsiella, Proteus, Enterococcus, and Pseudomonas aeruginosa, particularly in children with structural abnormalities or catheterization. Link to Genitourinary system MCQs

Risk factors and Presentation

Risk factors include vesicoureteral reflux, urinary tract obstruction, neurogenic bladder, constipation, poor perineal hygiene, and dysfunctional voiding. Clinical presentation varies with age: neonates and infants may present with nonspecific signs such as fever, poor feeding, vomiting, or irritability, whereas older children typically present with dysuria, frequency, urgency, abdominal pain, or flank pain.

Prevention

Because recurrent infections increase the risk of renal scarring, identifying children at risk and initiating preventive strategies — including behavioral measures and, when indicated, antibiotic prophylaxis — is an important component of pediatric care.

UTI Prophylaxis in Children

Drug	Dose (once daily unless stated)	Age suitability	When preferred	Important notes
Nitrofurantoin	1–2 mg/kg at bedtime	>1 month	First-line prophylaxis	Avoid if G6PD deficiency; may cause nausea
Trimethoprim-Sulfamethoxazole (TMP-SMX)	2 mg/kg (TMP component)	>2 months	Common first choice	Avoid in neonates; risk of Stevens-Johnson syndrome
Trimethoprim alone	2 mg/kg	>2 months	Alternative to TMP-SMX	Useful if sulfa allergy
Cephalexin	10–12 mg/kg	All ages	Infants & vesicoureteral reflux	Good safety profile
Amoxicillin	10–15 mg/kg	<2 months	Neonatal prophylaxis	Resistance common after infancy
Cefixime	2 mg/kg	>6 months	Resistant organisms	Used less commonly

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Indications for UTI Prophylaxis

• Vesicoureteral reflux (Grade III–V)
• Recurrent febrile UTIs (≥2 in 6 months or ≥3/year)
• Obstructive uropathy awaiting surgery
• Neurogenic bladder
• After first febrile UTI in infants until evaluation complete

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Duration

• Continue until:
  • VUR resolves or is surgically corrected
  • Child becomes toilet trained and infection-free
  • Specialist review recommends stopping

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Key Clinical Points

✔ Give at bedtime for maximal bladder concentration
✔ Encourage hydration & regular voiding
✔ Treat constipation (important risk factor)
✔ Monitor for breakthrough infections and resistance

Treatment of UTI in Children

Empirical Antibiotic Therapy (Based on Clinical Type)

Clinical Type	Oral Antibiotics (Outpatient)	IV Antibiotics (Inpatient / Severe)	Duration
Simple cystitis (Afebrile UTI)	Nitrofurantoin 5–7 mg/kg/day ÷ 2 doses Cephalexin 50–100 mg/kg/day ÷ 3–4 doses TMP-SMX 8–10 mg/kg/day (TMP component) ÷ 2 doses	Usually not required	5–7 days
Febrile UTI / Acute pyelonephritis	Cefixime 8 mg/kg/day OD Amoxicillin-clavulanate 40–50 mg/kg/day ÷ 2–3 doses	Ceftriaxone 50–75 mg/kg OD Cefotaxime 150 mg/kg/day ÷ 3 doses Gentamicin 5–7 mg/kg OD	7–14 days
Neonatal UTI (<2 months)	Not preferred	Ampicillin + Gentamicin OR Cefotaxime	10–14 days
Complicated UTI / Toxic child	Not preferred	Ceftriaxone ± Amikacin Consider Piperacillin-Tazobactam if resistant	10–14 days

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Organism-Specific Considerations

Organism	Preferred Drugs
Escherichia coli	Cephalosporins, Nitrofurantoin, TMP-SMX (if sensitive)
Proteus	Avoid Nitrofurantoin; use cephalosporins
Pseudomonas aeruginosa	Ceftazidime, Piperacillin-Tazobactam
Enterococcus	Ampicillin, Amoxicillin

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Supportive Management

Measure	Details
Hydration	Encourage oral fluids
Antipyretics	Paracetamol / Ibuprofen
Treat constipation	Important to prevent recurrence
Follow-up culture	If no improvement in 48 hours
Imaging	RBUS after first febrile UTI (especially <2 years)

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Important Clinical Points

✔ Send urine routine + culture before starting antibiotics
✔ Switch from IV to oral once clinically improved (24–48 hrs)
✔ Modify antibiotics according to culture sensitivity
✔ Admit if: toxic appearance, persistent vomiting, dehydration, neonate, poor follow-up

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Definition

Croup is an acute viral inflammatory disease of the upper airway involving the larynx, trachea, and bronchi, leading to subglottic edema and airway obstruction.

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Epidemiology

• Age: 6 months – 3 years (can occur up to 6 years)
• Male > Female
• Peak: Autumn & early winter
• Usually preceded by URTI

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Etiology

Viral (most common)

• Parainfluenza virus type 1 (most common)
• Parainfluenza 2 & 3
• RSV
• Influenza A & B
• Adenovirus
• Human metapneumovirus

Rare bacterial causes

• Mycoplasma
• Secondary bacterial infection (uncommon)

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Pathophysiology

• Viral infection → inflammation & edema of subglottic region
• Subglottis is the narrowest part of pediatric airway
• Small edema → marked increase in airway resistance
• Leads to inspiratory stridor & respiratory distress

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Clinical Features

Prodrome

• Low-grade fever
• Coryza
• Cough

Characteristic features

• Barking (seal-like) cough
• Hoarseness
• Inspiratory stridor
• Worse at night
• Aggravated by crying & agitation

Severe disease

• Stridor at rest
• Chest retractions
• Tachypnea
• Hypoxia
• Fatigue / altered sensorium (late sign)

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Severity Assessment (Westley Croup Score – concept)

Feature	Mild	Moderate	Severe
Stridor	None / with agitation	At rest	Loud, biphasic
Retractions	None	Mild–moderate	Severe
Air entry	Normal	Decreased	Markedly reduced
Cyanosis	None	None	Present
Mental status	Normal	Normal	Altered

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Investigations

• Diagnosis is clinical
• No routine labs required
• Neck X-ray (AP) (only if diagnosis unclear):
  • Steeple sign (subglottic narrowing)

⚠️ Avoid throat examination if severe obstruction suspected.

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Differential Diagnosis

Condition	Key Differentiating Feature
Epiglottitis	High fever, drooling, muffled voice
Bacterial tracheitis	Toxic child, high fever
Foreign body	Sudden onset, no prodrome
Retropharyngeal abscess	Neck stiffness, drooling
Angioedema	Facial/lip swelling

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Management

General Measures

• Keep child calm
• Minimal handling
• Oxygen if hypoxic
• Humidified air (comfort measure only)

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Pharmacological Treatment

1️⃣ Corticosteroids (All cases)

Dexamethasone (Dexona)

• Dose: 0.6 mg/kg
• Max: 10 mg
• Route: Oral / IM / IV
• Single dose usually sufficient

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2️⃣ Adrenaline Nebulization (Moderate–Severe)

L-Adrenaline (1:1000)

• Dose: 0.5 mL/kg (max 5 mL)
• Dilute with NS to 5 mL
• Rapid onset (10–15 min)
• Duration: ~2 hours

⚠️ Observe 2–4 hours after neb (rebound stridor)

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Indications for Admission

• Stridor at rest
• Need for repeated adrenaline
• Hypoxia
• Poor oral intake
• Age < 6 months
• Social concerns

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Indications for ICU / Intubation

• Exhaustion
• Altered consciousness
• Severe hypoxia
• Poor air entry
• Failure to respond to treatment

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Complications

• Respiratory failure
• Secondary bacterial infection
• Pneumonia
• Rarely death

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Prognosis

• Excellent
• Self-limiting (3–7 days)
• Recurrence possible

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Key Takeaway

• Single dose dexamethasone for all croup
• Adrenaline = temporary relief
• Steeple sign = croup
• Drooling → think epiglottitis
• Avoid agitation at all costs

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Febrile Seizures

Based on Nelson Textbook of Pediatrics, 21st Edition and recent updates

febrile seizures definition

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Introduction

Febrile seizures are the most common seizure disorder in childhood, occurring in association with fever but without evidence of central nervous system infection or acute electrolyte imbalance. They represent a benign, age-limited condition affecting genetically predisposed children.

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Epidemiology

• 
  

  Age group: 6 months to 5 years (peak: 12–18 months)

  
  
• 
  

  Incidence: ~2–5% of children in most populations

  
  
• 
  

  Recurrence rate: ~30–35% after first episode; higher in early onset (<1 year)

  
  
• 
  

  Family history: Positive in up to 25–40% cases, suggesting genetic susceptibility

  
  

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Definition (Nelson)

A febrile seizure is defined as a seizure accompanied by fever (>38°C or 100.4°F), without evidence of CNS infection, metabolic abnormality, or a history of afebrile seizures.

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Classification

1. Simple Febrile Seizure (SFS)

• 
  

  Generalized tonic-clonic in onset

  
  
• 
  

  Duration <15 minutes

  
  
• 
  

  Occurs once in 24 hours

  
  
• 
  

  No postictal neurological deficit

  
  

2. Complex (Atypical) Febrile Seizure (CFS)

• 
  

  Focal onset or focal features during/post seizure

  
  
• 
  

  Duration >15 minutes

  
  
• 
  

  Recurrent within 24 hours

  
  
• 
  

  May have postictal weakness (Todd’s paresis)

  
  

3. Febrile Status Epilepticus (FSE)

• 
  

  Febrile seizure lasting >30 minutes (or series lasting ≥30 min without full recovery)

  
  
• 
  

  Requires urgent management

  
  

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Etiopathogenesis

• Genetic predisposition:

  • 
    

    Polygenic inheritance; linkage to FEB1–FEB11 loci (e.g., FEB4 on 5q14–q15)

    
    
  • 
    

    GABRG2, SCN1A gene mutations implicated (especially when overlapping with GEFS+)

    
    

• Fever and cytokine response:

  • 
    

    Elevated IL-1β, IL-6, and TNF-α lower seizure threshold

    
    
  • 
    

    Rapid temperature rise rather than peak temperature triggers seizure

    
    

• Immature brain excitability:

  • 
    

    Age-dependent increased neuronal excitability due to GABA-A receptor subunit composition and immature synaptic inhibition

    
    

• Environmental factors:

  • 
    

    Viral infections (HHV-6, HHV-7, influenza, adenovirus, parainfluenza)

    
    
  • 
    

    Post-immunization (rare, within 24–72 hours, e.g., MMR)

    
    

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Clinical Features

• 
  

  Typically occur within 24 hours of fever onset

  
  
• 
  

  Usually generalized tonic-clonic lasting <5 minutes

  
  
• 
  

  Postictal drowsiness but quick recovery

  
  
• 
  

  No signs of meningitis (neck stiffness, photophobia, etc.)

  
  
• 
  

  No pre-existing neurological abnormality

  
  

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Evaluation

Goal: Exclude CNS infection, structural lesion, or metabolic cause.

History and examination:

• 
  

  Onset, duration, type of seizure

  
  
• 
  

  Timing relative to fever onset

  
  
• 
  

  Past neurological status, family history

  
  

Investigations:

• Lumbar puncture:

  • 
    

    Indicated if <12 months with incomplete immunization or signs of meningitis

    
    
  • 
    

    Optional in 12–18 months if unclear

    
    
  • 
    

    Not routinely needed in typical SFS

    
    

• EEG:

  • 
    

    Not indicated after first simple febrile seizure

    
    
  • 
    

    Consider if complex, focal, or abnormal development

    
    

• Neuroimaging:

  • 
    

    Not indicated for simple FS

    
    
  • 
    

    Consider MRI if focal deficits, prolonged seizures, or abnormal neurological findings

    
    

• Serum electrolytes, calcium, glucose:

  • 
    

    Only if atypical features or prolonged postictal state

    
    

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Differential Diagnosis

Condition	Distinguishing Feature
Meningitis/encephalitis	Signs of CNS infection, altered consciousness
Rigors	Consciousness maintained, no postictal phase
Epilepsy	Occurs without fever, may have preceding aura
Hypocalcemia, hypoglycemia	Biochemical abnormalities
CNS structural lesion	Focal deficits, developmental delay

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Management

Acute Episode

• 
  

  Ensure airway, breathing, circulation

  
  

• Abort seizure if >5 minutes:

  • 
    

    IV/rectal diazepam: 0.3–0.5 mg/kg

    
    
  • 
    

    IV lorazepam: 0.1 mg/kg (max 4 mg)

    
    
  • 
    

    IV midazolam (buccal/nasal): 0.2 mg/kg

    
    

• Control fever:

  • 
    

    Paracetamol 10–15 mg/kg/dose

    
    
  • 
    

    Tepid sponging (avoid cold water)

    
    

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Long-term Management

• 
  

  Antipyretics: No evidence they prevent recurrence

  
  

• Intermittent prophylaxis:

  • 
    

    Oral diazepam 0.3 mg/kg every 8 hr during febrile illness may reduce recurrence but causes sedation/ataxia

    
    
  • 
    

    Used only in high-risk cases (e.g., frequent recurrent FS, high parental anxiety)

    
    

• Continuous prophylaxis:

  • 
    

    Phenobarbital or valproate previously used but not recommended due to adverse effects and limited benefit

    
    

• Parental counseling:

  • 
    

    Excellent prognosis

    
    
  • 
    

    Not associated with brain damage, mental retardation, or epilepsy in most cases

    
    
  • 
    

    2–7% risk of later epilepsy (higher if complex, family history, or abnormal neurodevelopment)

    
    
  • 
    

    Educate about seizure first-aid: side positioning, not inserting objects in mouth, emergency use of rectal diazepam if >5 min

    
    

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Prognosis

• Recurrence risk factors:

  • 
    

    Age <12 months at first episode

    
    
  • 
    

    Family history of febrile seizure

    
    
  • 
    

    Low-grade fever at first seizure onset

    
    
  • 
    

    Short interval between fever onset and seizure

    
    

• Epilepsy risk:

  • 
    

    SFS: ~1–2%

    
    
  • 
    

    CFS: up to 4–6%

    
    
  • 
    

    FS with neurodevelopmental delay: up to 10%

    
    

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Recent Updates (per Nelson & AAP guidelines)

• 
  

  Continuous anticonvulsant prophylaxis not recommended for either simple or complex FS

  
  
• 
  

  Intermittent diazepam during febrile illness may be used selectively

  
  
• 
  

  Vaccination-associated febrile seizures do not contraindicate further vaccination

  
  
• 
  

  Genetic studies indicate overlap between FS and GEFS+ (Generalized Epilepsy with Febrile Seizures Plus), suggesting a spectrum

  
  

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Key Takeaways

• 
  

  Febrile seizures are benign, self-limited events related to fever in young children.

  
  
• 
  

  The mainstay of management is parental reassurance and acute seizure control, not long-term anticonvulsant therapy.

  
  
• 
  

  Investigations should focus on excluding CNS infection rather than diagnosing epilepsy.

  
  

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References:

1. 
   

   Kliegman RM, et al. Nelson Textbook of Pediatrics, 21st Edition, 2020.

   
   
2. 
   

   American Academy of Pediatrics. Guidelines for the Neurodiagnostic Evaluation of the Child with a Simple Febrile Seizure. Pediatrics, 2011.

   
   
3. 
   

   Shinnar S, et al. N Engl J Med, 2012;366:195–203.