Paediatric Sepsis

Quick Answer

One-liner: Paediatric sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection in children, characterised by age-specific physiological responses, "cold shock" predominance, higher fluid responsiveness, and the need for weight-based resuscitation with early vasoactive support.

Paediatric sepsis has an incidence of 48-89 per 100,000 children with mortality of 3-5% in high-income settings, rising to 10-25% with septic shock [1,2]. Key differences from adult sepsis include: cold shock is more common (high SVR, low CO, cold extremities, prolonged CRT), children are more fluid-responsive but can decompensate rapidly, and age-specific vital signs must be applied for recognition. The Surviving Sepsis Campaign Paediatric 2020 guidelines [3] recommend 10-20 mL/kg fluid boluses (up to 40-60 mL/kg in first hour) in ICU settings, with adrenaline or noradrenaline as first-line vasopressors (dopamine now second-line). The Phoenix Sepsis Criteria 2024 [4] now define paediatric sepsis based on organ dysfunction scoring, replacing the 2005 SIRS criteria. Pathogens vary by age: neonates (GBS, E. coli, Listeria), infants (S. pneumoniae, N. meningitidis), children (S. pneumoniae, S. aureus, S. pyogenes). Aboriginal and Torres Strait Islander children have 2-3x higher rates of invasive bacterial disease. ICU management focuses on early antibiotics, weight-based fluid resuscitation, early vasoactive support, and source control [5].

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CICM Exam Focus

What Examiners Expect

Second Part Written (SAQ):

Common SAQ stems:

• "A 2-year-old child presents to your ICU with fever, tachycardia, and cold mottled peripheries. HR 180, BP 70/40, RR 50, SpO2 90% on 4L O2, CRT 5 seconds. Lactate is 6.5 mmol/L. Outline your initial assessment and management."
• "A 6-month-old infant is admitted with meningococcal septicaemia and petechial rash evolving to purpura. Blood cultures are positive for Neisseria meningitidis. Discuss your management priorities in the first 6 hours."
• "Compare and contrast the presentation and management of paediatric sepsis with adult sepsis, with reference to current guidelines."

Expected depth:

• Age-specific vital signs and recognition of abnormal parameters
• Understanding of cold shock versus warm shock in children
• Weight-based fluid resuscitation (mL/kg) with reassessment after each bolus
• Vasoactive agent selection based on shock phenotype
• Age-appropriate antimicrobial choices
• Recognition of pathogens by age group
• Phoenix criteria (2024) vs SIRS criteria (2005)

Second Part Hot Case:

Typical presentations:

• Febrile infant (3 months old) in ED referral with tachycardia, poor feeding, and lethargy
• School-age child with meningococcal purpura fulminans on multiple vasopressors
• Post-operative patient Day 3 with fever, tachycardia, and increasing oxygen requirements
• Immunocompromised child (oncology patient) with febrile neutropenia and shock

Examiners assess:

• Systematic A-E assessment with paediatric-specific considerations
• Recognition of cold shock features (CRT, mottling, temperature gradient)
• Appropriate weight-based calculations for fluids and drugs
• Knowledge of paediatric normal values for age
• Antimicrobial choices appropriate for age and suspected source
• Family communication and Indigenous health awareness
• Recognition of complications (DIC, ARDS, AKI)

Second Part Viva:

Expected discussion areas:

• Age-related physiological differences affecting sepsis presentation
• Immune system development and pathogen susceptibility
• Cold shock vs warm shock pathophysiology
• Evidence base for fluid resuscitation (FEAST trial, SSC 2020)
• Vasoactive agent pharmacology in children
• Hydrocortisone for refractory shock
• Long-term sequelae of paediatric sepsis
• Indigenous health disparities in invasive bacterial disease

Common Mistakes

• Using adult vital sign thresholds - Tachycardia is age-dependent (infant HR 180 is more concerning than adolescent HR 110)
• Underestimating cold shock - Not recognising prolonged CRT and cold extremities as signs of shock
• Over-reliance on blood pressure - Hypotension is a LATE sign in children; shock can exist with normal BP
• Incorrect fluid volumes - Forgetting weight-based calculations (mL/kg)
• Choosing dopamine first - Guidelines now recommend adrenaline/noradrenaline first-line
• Wrong antibiotic spectrum for age - Missing age-appropriate pathogen coverage
• Not reassessing after each fluid bolus - Failure to detect fluid overload early

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Key Points

Key Points: The 10 things you MUST know for CICM Second Part:

1. Cold shock predominates in children: Unlike adults (warm shock), children typically present with cold extremities, prolonged CRT (greater than 3 seconds), mottled skin, and narrow pulse pressure despite tachycardia

2. Age-specific vital signs are essential: Know the age-appropriate thresholds for HR, RR, BP (hypotension is age-dependent: SBP less than 70 + (2 x age in years) for ages 1-10)

3. Fluid resuscitation: 10-20 mL/kg boluses, reassess after EACH bolus, up to 40-60 mL/kg in first hour in ICU settings; more cautious approach without ICU access (FEAST influence)

4. First-line vasopressors: Adrenaline (epinephrine) or noradrenaline (norepinephrine) - NOT dopamine (now second-line per SSC 2020)

5. Age-specific pathogens: Neonates (GBS, E. coli, Listeria), Infants (S. pneumoniae, N. meningitidis), Children (S. pneumoniae, S. aureus, S. pyogenes)

6. Phoenix Criteria 2024: New sepsis definition - Phoenix Sepsis Score greater than or equal to 2 with suspected infection; septic shock = cardiovascular score greater than or equal to 1

7. Hypotension is LATE: Children maintain BP through tachycardia and vasoconstriction; by the time BP drops, they are in decompensated shock

8. Meningococcal disease: Petechiae evolving to purpura = medical emergency; ceftriaxone + ICU admission; notify public health

9. Hydrocortisone: For fluid-refractory, catecholamine-resistant shock; dose 50 mg/m² (or 1-2 mg/kg) in divided doses

10. Indigenous health: Aboriginal and Torres Strait Islander children have 2-3x higher rates of invasive bacterial disease; cultural safety, AHW/ALO involvement essential

Memory Aids

SEPTIC CHILD Mnemonic:

• Skin mottling, prolonged CRT (cold shock signs)
• Early antibiotics (within 1 hour of recognition)
• Perfusion poor despite tachycardia
• Tachycardia age-appropriate thresholds
• IV access x 2, intraosseous if needed
• Crystalloid 10-20 mL/kg boluses, reassess each time
• Catecholamines early (adrenaline/noradrenaline)
• Hydrocortisone if refractory
• Investigate source (cultures before antibiotics)
• Lactate (greater than 2 mmol/L concerning)
• Defibrillator and resuscitation equipment ready

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Definition and Epidemiology

Definitions

Historical Definition - SIRS Criteria (2005) [6]: The International Pediatric Sepsis Consensus Conference (IPCC 2005) defined paediatric SIRS as 2 or more of the following criteria (one must be temperature or WBC):

Age-Specific Heart Rate and Respiratory Rate Thresholds:

Current Definition - Phoenix Sepsis Criteria (2024) [4]:

The Society of Critical Care Medicine Paediatric Sepsis Definition Task Force released the Phoenix criteria in 2024:

Paediatric Sepsis: Suspected infection PLUS Phoenix Sepsis Score ≥ 2 points

Paediatric Septic Shock: Sepsis PLUS Cardiovascular Score ≥ 1 point

Phoenix Sepsis Score Components (0-13 points):

Clinical Significance: Phoenix criteria have higher specificity than SIRS (reduces over-diagnosis from viral illness) and better predict mortality across resource settings.

Epidemiology

Global Data:

Australian/NZ Data (ANZPIC Registry, AIHW):

• Paediatric sepsis accounts for 10-15% of PICU admissions [13]
• Invasive bacterial disease incidence: 15-25 per 100,000 children under 5 years [14]
• N. meningitidis: 1-2 per 100,000 with peak in under 5 years and 15-24 years [15]
• Mortality for PICU-admitted sepsis: 4-8% [13]

Age Distribution:

• Highest incidence in infants less than 1 year (especially neonates)
• Second peak in adolescents (meningococcal disease)
• Neonatal sepsis: 1-5 per 1000 live births (higher in preterm) [16]

Risk Factors:

Non-modifiable:

• Age (less than 1 year, especially less than 3 months)
• Prematurity and low birth weight
• Male sex (1.5x higher risk)
• Genetic susceptibility (complement deficiencies, asplenia)
• Aboriginal/Torres Strait Islander or Maori ethnicity

Modifiable/Acquired:

• Immunocompromised states (oncology, transplant, immunodeficiency)
• Chronic illness (cardiac, pulmonary, neurological)
• Malnutrition
• Indwelling devices (central lines, tracheostomy, VP shunt)
• Recent surgery or hospitalisation
• Incomplete vaccination

High-Risk Populations:

Pathogen Spectrum by Age

Special Populations:

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Applied Basic Sciences

Age-Related Physiological Differences

Cardiovascular Physiology:

Clinical Implication: Children are rate-dependent for cardiac output. They compensate for shock primarily through tachycardia and vasoconstriction. When these mechanisms fail (bradycardia, hypotension), decompensation is rapid and catastrophic [19].

Respiratory Physiology:

Clinical Implication: High oxygen consumption and low FRC mean children desaturate rapidly during respiratory failure. Respiratory compensation for metabolic acidosis is limited by high baseline respiratory rate [20].

Metabolic Considerations:

Clinical Implication: Monitor glucose closely in paediatric sepsis; hypoglycaemia is common and harmful [21].

Immune System Development

Neonatal Immune Deficiencies:

Vulnerability by Age:

• 0-3 months: Highest risk - waning maternal antibodies, immature immune system, incomplete vaccination
• 3-6 months: Maternal antibody nadir
• 6-24 months: Developing immunity, vaccination response building
• Greater than 2 years: Near-adult immune function for most pathogens

Pathophysiology of Paediatric Sepsis

Cold Shock vs Warm Shock [22,23]:

Why Cold Shock Predominates in Children:

1. Limited myocardial reserve (rate-dependent CO)
2. Higher baseline sympathetic tone
3. More efficient vasoconstriction response
4. Sepsis-induced myocardial dysfunction common

Haemodynamic Progression:

1. Compensated shock: Tachycardia, vasoconstriction, normal BP, prolonged CRT
2. Decompensated shock: Hypotension, altered consciousness, acidosis
3. Irreversible shock: Multiorgan failure, refractory to treatment

Cellular Pathophysiology (same as adult sepsis):

• Pattern recognition receptors (TLRs, NOD-like receptors) detect PAMPs
• Cytokine cascade (IL-1, IL-6, TNF-alpha)
• Endothelial activation and dysfunction
• Coagulation activation (DIC)
• Mitochondrial dysfunction
• Organ dysfunction cascade

Pharmacology in Children

Pharmacokinetic Differences:

Vasoactive Agents:

Antimicrobials by Age:

Hydrocortisone for Refractory Shock [24]:

• Indication: Fluid-refractory, catecholamine-resistant shock
• Dose: 50 mg/m²/day (or 1-2 mg/kg) in divided doses q6h
• Stress-dose hydrocortisone for adrenal insufficiency risk (pituitary/adrenal disease, chronic steroids)
• Evidence limited but reasonable in refractory cases

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Clinical Presentation

Recognition Challenges

Why Paediatric Sepsis is Missed:

1. Normal vital signs vary by age - Tachycardia of 180 is concerning in a 5-year-old but may be normal in a febrile infant
2. Non-specific symptoms - Lethargy, poor feeding, irritability can be many things
3. Blood pressure preserved until late - Hypotension is LATE; shock exists with normal BP
4. Parental concern undervalued - "Not quite right" should trigger investigation
5. Fever without source - Common in infants, most are viral but some are bacterial

Clinical Features by Shock Type

Cold Shock Presentation (more common in children):

• Tachycardia (age-appropriate)
• Prolonged capillary refill time (greater than 3 seconds)
• Cold, mottled extremities with central-peripheral temperature gap
• Narrow pulse pressure
• Weak peripheral pulses (may be normal central)
• Mental status changes (irritability, lethargy)
• Reduced urine output
• Blood pressure may be NORMAL initially (compensated)

Warm Shock Presentation (less common in children):

• Tachycardia
• Flash capillary refill (less than 1 second)
• Warm, flushed peripheries
• Wide pulse pressure (bounding pulses)
• Hypotension (often present)
• Mental status changes

Age-Specific Presentations

Neonates (0-28 days):

• Often non-specific: Temperature instability (fever OR hypothermia), poor feeding, lethargy, irritability, jaundice
• Respiratory distress, apnoea
• Abdominal distension (late)
• "Not looking right"
• parental concern is valid

Infants (1-12 months):

• Fever (may be absent in young infants)
• Irritability or lethargy
• Poor feeding
• Tachypnoea
• Bulging fontanelle (if meningitis)
• Mottled, cool extremities

Children (1-12 years):

• Fever with systemic symptoms
• Tachycardia, tachypnoea
• Altered mental status
• Rash (petechiae/purpura concerning for meningococcus)
• Localising symptoms (cough, dysuria, abdominal pain)

Adolescents (12-18 years):

• More adult-like presentation
• May present with warm shock
• Meningococcal disease peak age group

Red Flag Features

Meningococcal Disease (Special Consideration)

Recognition:

• Prodrome: Non-specific (fever, malaise, headache) - can be mistaken for viral illness
• Petechiae/purpura: Start as small spots, may rapidly coalesce
• "Glass test": Petechiae do not blanch with pressure
• Can progress from well to critically unwell in hours
• Purpura fulminans: Extensive purpura with DIC

Key Points:

• Do NOT delay antibiotics for LP if meningococcal disease suspected
• Ceftriaxone 50-100 mg/kg (max 2g) IV immediately
• Notify public health for contact prophylaxis
• High mortality if delayed treatment [25]

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Investigations

Laboratory Investigations

Bedside:

• ABG/VBG: Lactate (most important), pH, base deficit, glucose
  • "Lactate greater than 2 mmol/L: Concerning"
  • "Lactate greater than 4 mmol/L: High risk"
• Blood glucose: Hypoglycaemia common (monitor frequently)
• Capillary refill time: Quantify (normal less than 2-3 seconds)

Blood Tests:

Cultures (obtain BEFORE antibiotics if possible, but do NOT delay treatment):

• Blood cultures: Minimum 2 mL per bottle in infants, 5-10 mL in children; paired cultures if central line
• Urine: Catheter specimen or suprapubic aspirate in infants; bag urine unreliable
• Lumbar puncture: If meningitis suspected AND safe to perform (no signs of raised ICP)
  • "CSF: Cell count, protein, glucose, Gram stain, culture, PCR (meningococcal, pneumococcal, viral)"
• Other: Wound swab, sputum, stool if clinically indicated

LP Contraindications/Deferral:

• Haemodynamic instability
• Coagulopathy (platelets less than 100, INR greater than 1.5)
• Signs of raised ICP (focal neurology, abnormal posturing, papilloedema)
• Skin infection over LP site
• Cardiorespiratory compromise
• Do NOT delay antibiotics to perform LP

Imaging

Chest X-Ray:

• Pneumonia (consolidation, effusion)
• Pulmonary oedema (fluid overload)
• ARDS changes
• Line position

Point-of-Care Ultrasound:

• Cardiac: Assess cardiac function (qualitative), pericardial effusion
• IVC: Fluid responsiveness (collapsibility index)
• Lung: B-lines (pulmonary oedema), consolidation, effusion
• Abdominal: Free fluid, abscess, appendicitis

CT Imaging:

• CT head: If LP contraindicated, signs of raised ICP
• CT abdomen: Intra-abdominal source (appendicitis, abscess)
• CT chest: If CXR inconclusive

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ICU Management

Surviving Sepsis Campaign Paediatric 2020 - Key Recommendations [3]

Hour-1 Bundle:

1. Obtain blood cultures (before antibiotics if possible)
2. Administer broad-spectrum antibiotics (within 1 hour of recognition)
3. Measure lactate (remeasure if greater than 2 mmol/L)
4. Begin fluid resuscitation (if abnormal perfusion)
5. Start vasoactive support (if fluid-refractory shock)

Initial Resuscitation (First Hour)

A - Airway:

• Assessment: Airway patency, secretions, stridor
• Positioning: Neutral position in infants (large occiput)
• Intervention threshold: Lower than adults (rapid desaturation)
• Intubation considerations:
  • "ETT size: (Age/4) + 4 uncuffed, or (Age/4) + 3.5 cuffed"
  • "RSI drugs: Ketamine (haemodynamically stable), fentanyl + rocuronium"
  • Anticipate hypotension post-intubation

B - Breathing:

• Oxygen: High-flow initially, target SpO2 94-98%
• NIV: HFNC or CPAP if respiratory distress without exhaustion
• Intubation indications:
  • Respiratory failure despite NIV
  • Altered consciousness (GCS less than 8)
  • Need for other interventions (procedures)
  • Anticipated deterioration

C - Circulation:

Key Points: Fluid Resuscitation Algorithm (SSC 2020):

IN ICU SETTINGS (MV and vasopressors available):

1. Give 10-20 mL/kg balanced crystalloid bolus over 5-20 minutes
2. Reassess after EACH bolus (clinical signs, hepatomegaly, lung crackles)
3. Repeat up to 40-60 mL/kg in first hour if needed
4. Stop fluids if signs of fluid overload develop
5. Start vasoactive if shock persists after adequate fluid resuscitation

WITHOUT ICU ACCESS (FEAST setting):

1. If NOT hypotensive: Maintenance fluids only
2. If hypotensive: Cautious 10-20 mL/kg boluses with frequent reassessment
3. More restrictive fluid approach to prevent fluid overload without ventilator support

Fluid Choice:

• Balanced crystalloid preferred (Plasma-Lyte, Hartmann's) over 0.9% saline [26]
• Avoid 5% dextrose (hypotonic, no intravascular expansion)
• Albumin 4-5%: May be considered if large volume crystalloid given (greater than 60 mL/kg)

Vascular Access:

• Two peripheral IV access attempts
• If unsuccessful within 5 minutes: Intraosseous (IO) access [27]
  • Proximal tibia (most common), distal femur, proximal humerus
  • IO can be used for all resuscitation drugs and fluids
• Central venous access: For vasoactive infusions, central venous monitoring

Vasopressor/Inotrope Selection:

SSC 2020 Key Change: Dopamine is now second-line (associated with more arrhythmias) [3]

D - Disability:

• GCS monitoring
• Glucose: Check frequently, treat hypoglycaemia (less than 2.6 mmol/L)
  • "Bolus: Dextrose 10% 2-5 mL/kg IV"
• Sedation if intubated: Fentanyl/morphine + midazolam
• Seizures: Treat aggressively (may be sign of meningitis)

E - Exposure/Environment:

• Temperature: Treat fever (paracetamol), treat hypothermia (rewarming)
• Skin: Look for rash (petechiae, purpura, mottling)
• Source: Identify likely infection source

Antimicrobial Therapy

Principles:

• Within 1 hour of sepsis recognition [28]
• Broad-spectrum empiric, narrowed when cultures available
• Age-appropriate coverage (see pathogen table above)
• Dose for severe infection (higher end of dosing range)

Empiric Regimens by Age (Therapeutic Guidelines Australia):

Meningococcal Disease Antibiotics:

• Ceftriaxone 50-100 mg/kg (max 2g) stat, then 50 mg/kg q12h (max 4g/day)
• Duration: 5-7 days for meningococcaemia, 7 days for meningitis

Dexamethasone in Meningitis [29]:

• Give BEFORE or WITH first antibiotic dose (ideally within 1 hour)
• Dose: 0.15 mg/kg q6h for 4 days
• Benefit: Reduces hearing loss in H. influenzae meningitis, probable benefit in pneumococcal
• Less clear benefit if given after antibiotics started

Source Control

• Drainage of abscess (surgical or interventional)
• Removal of infected devices (central line, VP shunt)
• Debridement of infected/necrotic tissue
• Appendicectomy/laparotomy for intra-abdominal source
• Urgent consultation with relevant surgical specialties

Corticosteroids in Refractory Shock

Indication [24]:

• Fluid-refractory AND catecholamine-resistant shock
• Suspected or known adrenal insufficiency

Regimen:

• Hydrocortisone: 50 mg/m²/day OR 1-2 mg/kg/dose q6h (max 50 mg/dose)
• Alternative: Hydrocortisone loading 2 mg/kg then 1 mg/kg q6h

Evidence:

• Limited RCT data in children
• Physiological rationale: Relative adrenal insufficiency in septic shock
• SSC 2020: Weak recommendation, conditional on fluid and vasopressor-resistant shock

Monitoring and Reassessment

Clinical Targets:

• Perfusion: CRT less than 3 seconds, warm extremities
• Heart rate: Normalising for age
• Blood pressure: Age-appropriate (not hypotensive)
• Mental status: Improving alertness
• Urine output: Greater than 1 mL/kg/hr (infants), greater than 0.5 mL/kg/hr (children)
• Lactate clearance: Greater than 10-20% reduction in 2-4 hours

Investigations to Monitor:

• ABG/VBG: Lactate, pH, base deficit q2-4h initially
• FBC, UEC, LFT: Daily
• Coagulation: If DIC suspected
• Blood glucose: Frequent (q1-2h in young children)

Advanced Monitoring (if available):

• Arterial line for continuous BP monitoring
• Central venous catheter for CVP, ScvO2 monitoring
• Echocardiography for cardiac function assessment
• Near-infrared spectroscopy (NIRS) for tissue oxygenation

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Differences from Adult Sepsis

Summary Table

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ANZICS/ANZPIC Context

Australian and New Zealand Practice

ANZPIC Registry Data [13]:

• Paediatric sepsis accounts for 10-15% of PICU admissions
• Mortality: 4-8% for PICU-admitted sepsis
• Meningococcal disease: Declining with vaccination, but outbreaks occur
• Pneumococcal disease: Reduced with PCV13 vaccination

Key Australian Considerations:

• Vaccination programs: High coverage for Hib, PCV13, MenACWY, MenB
• Indigenous health: Higher disease burden requires targeted intervention
• Remote access: Retrieval medicine considerations for rural/remote patients
• Antibiotic stewardship: Balance between early antibiotics and resistance

Retrieval Medicine:

• Royal Flying Doctor Service (RFDS), NETS, Careflight for paediatric retrievals
• Telemedicine consultation available from tertiary PICUs
• Stabilisation before transfer: Fluids, antibiotics, vasoactives via IO if needed
• Aeromedical considerations: Lower cabin pressure, monitoring in transit

Indigenous Health Considerations

Maori Health Considerations

New Zealand Context:

• Maori children: 2x higher rates of invasive bacterial disease [18]
• Similar socioeconomic and access barriers
• Involve Maori Health Workers
• Acknowledge whanau (extended family) in decision-making
• Consider karakia (spiritual practices) if requested

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Prognosis and Outcomes

Mortality

Short-Term Outcomes:

Factors Associated with Mortality:

• Delayed recognition and treatment
• Catecholamine-resistant shock
• Multiple organ dysfunction (3+ organs)
• High lactate (greater than 4 mmol/L) that fails to clear
• Underlying immunocompromise
• Meningococcal purpura fulminans

Long-Term Sequelae

Post-Sepsis Morbidity [30,31]:

• Neurodevelopmental impairment (especially meningitis survivors)
• Hearing loss (post-meningitis, aminoglycoside exposure)
• Renal impairment
• Limb amputation (purpura fulminans, vasopressor extravasation)
• Skin scarring (purpura, burns)
• Psychological sequelae (PTSD, anxiety in child and family)
• Educational and cognitive difficulties

Meningitis Sequelae:

• Hearing loss: 10-30% (pneumococcal greater than meningococcal)
• Cognitive impairment: 10-20%
• Seizures/epilepsy: 5-10%
• Hydrocephalus: 2-5%
• Motor deficits: 5-10%

Prognostic Scores

PELOD-2 (Paediatric Logistic Organ Dysfunction-2) [32]:

• Components: Glasgow Coma Scale, pupillary reaction, lactatemia, MAP, creatinine, PaO2/FiO2, ventilation, WCC, platelets
• Validated for PICU mortality prediction

pSOFA (Paediatric SOFA) [33]:

• Age-adjusted SOFA score for organ dysfunction quantification
• Similar components to adult SOFA with paediatric thresholds

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SAQ Practice Questions

SAQ 1: Infant with Septic Shock

Time Allocation: 10 minutes Total Marks: 20

Stem: An 8-month-old infant (weight 8 kg) is transferred to your PICU from the Emergency Department with fever and poor perfusion. She was previously well with no significant past medical history and is fully vaccinated.

On arrival to PICU:

• HR: 185 bpm
• BP: 75/45 mmHg
• RR: 55/min
• SpO2: 92% on 4L nasal prong O2
• Temperature: 39.2°C
• CRT: 4 seconds centrally
• Cool, mottled extremities
• Lethargic but responsive to pain

Investigations:

• ABG: pH 7.22, PaCO2 28, PaO2 75, HCO3 12, Lactate 6.8 mmol/L
• FBC: Hb 95, WCC 24 x 10⁹/L, Platelets 85 x 10⁹/L
• CRP: 285 mg/L
• Blood glucose: 2.4 mmol/L
• Blood cultures: Pending

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Question 1.1 (8 marks)

Describe your immediate assessment and management priorities in the first hour.

Model Answer:

Systematic A-E Assessment (2 marks):

• A: Airway patent, no stridor or obstruction
• B: Tachypnoea with increased work of breathing, hypoxia requiring supplemental oxygen
• C: Shock with cold peripheries, prolonged CRT, tachycardia - this is COLD SHOCK
• D: Altered mental status (lethargic), hypoglycaemia
• E: Fever, mottled skin, no rash visible

Immediate Resuscitation (4 marks):

Vascular Access:

• Establish second IV or intraosseous access (0.5 marks)
• Collect blood cultures before antibiotics if possible (0.5 marks)

Hypoglycaemia Correction:

• Dextrose 10% 2-5 mL/kg IV (approximately 16-40 mL) immediately (0.5 marks)
• Recheck glucose in 15 minutes (0.5 marks)

Fluid Resuscitation:

• Balanced crystalloid 20 mL/kg (160 mL) over 10-15 minutes (0.5 marks)
• Reassess after EACH bolus for clinical response and fluid overload signs (0.5 marks)
• Repeat boluses up to 40-60 mL/kg (320-480 mL) in first hour if still in shock (0.5 marks)

Antibiotics:

• Ceftriaxone 50 mg/kg (400 mg) IV within 1 hour of recognition (0.5 marks)

Vasoactive Support:

• If shock persists after 40-60 mL/kg fluids, start adrenaline 0.05-0.1 mcg/kg/min (cold shock pattern) (1 mark)

Team Notification (2 marks):

• PICU consultant/senior registrar (0.5 marks)
• Infectious diseases team for antimicrobial guidance (0.5 marks)
• Prepare for intubation if deterioration (0.5 marks)
• Alert blood bank for potential transfusion needs (0.5 marks)

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Question 1.2 (6 marks)

The infant does not respond to 60 mL/kg of fluid resuscitation and you commence adrenaline infusion. Lactate remains at 5.5 mmol/L after 2 hours. Outline your further management.

Model Answer:

Escalation of Vasoactive Support (2 marks):

• Increase adrenaline titrating to clinical endpoints (CRT, BP, HR) (0.5 marks)
• Consider adding noradrenaline if pure vasodilation component (0.5 marks)
• Consider vasopressin 0.0003-0.002 units/kg/min as adjunct if catecholamine-refractory (0.5 marks)
• Central venous access for inotrope infusion and monitoring (0.5 marks)

Airway and Ventilation (1 mark):

• Intubation likely needed given severity and need for multiple interventions (0.5 marks)
• Lung-protective ventilation, cautious with PPV in hypotension (0.5 marks)

Hydrocortisone for Refractory Shock (1 mark):

• This is fluid-refractory, catecholamine-resistant shock - consider stress-dose hydrocortisone (0.5 marks)
• Dose: 1-2 mg/kg q6h or 50 mg/m² daily divided (0.5 marks)

Additional Investigations and Management (1 mark):

• Echocardiography to assess cardiac function and guide inotrope choice (0.5 marks)
• Consider blood products: FFP, platelets if DIC (0.5 marks)

Reassessment and Goals (1 mark):

• Target: CRT less than 3 seconds, lactate clearance greater than 10-20%, urine output greater than 1 mL/kg/hr (0.5 marks)
• Source control: LP if safe, imaging for occult source (0.5 marks)

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Question 1.3 (6 marks)

Blood cultures return positive for Streptococcus pneumoniae. Discuss your antimicrobial management and any public health considerations.

Model Answer:

Antimicrobial Management (3 marks):

Current Regimen Review:

• Ceftriaxone appropriate for S. pneumoniae (first-line) (0.5 marks)
• Check MIC for penicillin/ceftriaxone sensitivity when available (0.5 marks)

Dosing for Severe Infection:

• Continue ceftriaxone 50 mg/kg q12-24h (higher frequency if meningitis) (0.5 marks)
• If meningitis suspected: Increase to 100 mg/kg/day divided q12h (max 4g/day) (0.5 marks)

Duration:

• Bacteraemia without focus: 10-14 days (0.5 marks)
• Meningitis: 10-14 days (0.5 marks)

Public Health and Preventive Considerations (3 marks):

Vaccination History:

• Confirm infant's vaccination status - should have received PCV13 at 2, 4, 6 months (0.5 marks)
• If breakthrough disease despite vaccination: Report to public health for serotype surveillance (0.5 marks)

Family Counselling:

• Explain diagnosis and treatment plan (0.5 marks)
• Discuss prognosis and potential complications (hearing loss if meningitis) (0.5 marks)

Follow-up:

• Audiology assessment if meningitis (0.5 marks)
• Immunology referral if recurrent invasive bacterial disease or unusual serotype (0.5 marks)

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SAQ 2: Meningococcal Sepsis

Time Allocation: 10 minutes Total Marks: 20

Stem: A 14-year-old boy (weight 50 kg) presents to the Emergency Department with a 6-hour history of fever, headache, and a rapidly spreading rash. His parents report he was well yesterday but woke with flu-like symptoms this morning.

On arrival:

• HR: 135 bpm
• BP: 85/50 mmHg
• RR: 32/min
• SpO2: 94% room air
• Temperature: 39.8°C
• GCS: 13/15 (confused)
• Rash: Widespread petechiae on trunk and limbs, some coalescing into purpura on lower legs

Investigations:

• Blood glucose: 5.2 mmol/L
• Lactate: 8.5 mmol/L
• FBC: WCC 2.5 x 10⁹/L, Platelets 45 x 10⁹/L
• Coag: PT 22s, APTT 58s, Fibrinogen 1.2 g/L
• Lumbar puncture deferred due to coagulopathy

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Question 2.1 (8 marks)

What is the most likely diagnosis? Outline your immediate management priorities.

Model Answer:

Diagnosis (2 marks):

• Meningococcal septicaemia with purpura fulminans and DIC (1 mark)
• Likely causative organism: Neisseria meningitidis (1 mark)

Supporting Features:

• Rapid onset (6 hours)
• Petechial rash evolving to purpura
• Shock (hypotension, tachycardia)
• High lactate, leukopenia, thrombocytopenia, coagulopathy (DIC)

Immediate Management (6 marks):

Antibiotics (1.5 marks):

• Ceftriaxone 100 mg/kg (max 2g) IV STAT - do NOT delay for investigations (1 mark)
• Ideally given within minutes of suspected diagnosis (0.5 marks)

Resuscitation (2 marks):

• High-flow oxygen (0.5 marks)
• IV access x 2 or IO if difficult (0.5 marks)
• Fluid bolus 20 mL/kg (1000 mL) balanced crystalloid over 15-20 minutes (0.5 marks)
• Prepare for vasoactive support (noradrenaline for warm shock, likely in adolescent) (0.5 marks)

Coagulopathy Management (1 mark):

• Transfuse platelets (target greater than 50 for active bleeding/DIC) (0.5 marks)
• Fresh frozen plasma (15-20 mL/kg) for coagulopathy (0.5 marks)

ICU Transfer (0.5 marks):

• Immediate PICU admission for vasoactive support and monitoring (0.5 marks)

Notification (1 mark):

• Public health notification - meningococcal disease is notifiable (0.5 marks)
• Contact tracing for close contacts (household, intimate contacts) will need chemoprophylaxis (0.5 marks)

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Question 2.2 (6 marks)

Despite 60 mL/kg fluid resuscitation and noradrenaline infusion, the patient remains hypotensive with BP 80/45, HR 140, and lactate 9.2 mmol/L. The purpuric rash is extending rapidly. Discuss your escalation strategy.

Model Answer:

Vasoactive Escalation (2 marks):

• Increase noradrenaline infusion (titrate to MAP target) (0.5 marks)
• Add vasopressin 0.0003-0.002 units/kg/min (0.5 marks)
• Consider adrenaline if evidence of myocardial dysfunction (0.5 marks)
• Central venous access for monitoring and infusions (0.5 marks)

Hydrocortisone (1 mark):

• Stress-dose hydrocortisone indicated for catecholamine-refractory shock (0.5 marks)
• Dose: 50 mg q6h (adolescent weight-based) (0.5 marks)

Airway Management (1 mark):

• Intubation likely required given severity and need for multiple interventions (0.5 marks)
• RSI with ketamine (haemodynamically stable induction) and rocuronium (0.5 marks)

DIC Management (1 mark):

• Ongoing blood product support: Platelets, FFP, cryoprecipitate (for fibrinogen less than 1.5 g/L) (0.5 marks)
• Consider packed red cells if Hb dropping (0.5 marks)

Prognostic Considerations (1 mark):

• Discuss with family: This is severe meningococcal disease with high mortality risk (0.5 marks)
• Prepare for potential ECMO consideration if cardiac function deteriorating and available (0.5 marks)

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Question 2.3 (6 marks)

The patient stabilises after 24 hours and begins to improve. Discuss the public health management, antibiotic duration, and follow-up considerations.

Model Answer:

Public Health Management (2 marks):

• Notify public health department (statutory notification in Australia) (0.5 marks)
• Contact prophylaxis for close contacts within 7 days of diagnosis (0.5 marks):
  • Household contacts
  • Kissing contacts
  • Childcare/school contacts with prolonged close contact
• Prophylaxis regimen: Ciprofloxacin 500 mg single dose (adults) or Ceftriaxone 250 mg IM (0.5 marks)
• Index case also receives clearance antibiotics (ceftriaxone already given) (0.5 marks)

Antibiotic Duration (1.5 marks):

• Meningococcaemia (without meningitis): 5-7 days ceftriaxone (0.5 marks)
• If meningitis confirmed: 7 days (0.5 marks)
• De-escalate if sensitivities allow (penicillin if sensitive) (0.5 marks)

Follow-up Considerations (2.5 marks):

Immediate Complications:

• Limb assessment for compartment syndrome, skin necrosis (purpura fulminans may require debridement/grafting) (0.5 marks)
• Renal function monitoring (AKI from shock/DIC) (0.5 marks)

Medium-term:

• Plastic surgery/wound care follow-up if skin necrosis (0.5 marks)
• Rehabilitation if prolonged ICU stay (0.5 marks)

Long-term:

• Psychological support for patient and family (PTSD common) (0.5 marks)
• Vaccination: Complete meningococcal vaccination series (MenACWY, MenB) after recovery (immunity from natural infection may be serogroup-specific) (0.5 marks)

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Viva Scenarios

Viva 1: Fluid Resuscitation in Paediatric Sepsis

Stem: "You are discussing paediatric sepsis management with a junior registrar who asks about the FEAST trial. They want to understand why fluid resuscitation recommendations differ between settings."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Examiner: "What was the FEAST trial and what were its key findings?"

Model Answer:

The FEAST trial (Fluid Expansion as Supportive Therapy) was a landmark randomised controlled trial published in NEJM in 2011 (PMID: 21615299) [34].

Population:

• 3,141 African children (median age 24 months) with severe febrile illness and impaired perfusion
• Conducted in Kenya, Uganda, and Tanzania
• Settings with limited or no access to mechanical ventilation or ICU care

Intervention:

• Three arms: 20-40 mL/kg 0.9% saline bolus vs 20-40 mL/kg 5% albumin bolus vs no bolus (control - maintenance fluids only)

Key Findings:

• Increased mortality in both fluid bolus groups compared to control
• 48-hour mortality: Saline 10.5%, Albumin 10.6%, Control 7.3%
• Absolute risk increase of 3.3% (NNH approximately 30)

Proposed Mechanisms for Harm:

• Fluid overload in setting without ventilator support
• Reperfusion injury
• Electrolyte shifts
• Ischaemia-reperfusion in hearts with subclinical viral myocarditis

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Examiner: "How have the SSC 2020 Paediatric Guidelines incorporated these findings?"

Model Answer:

The SSC 2020 guidelines now stratify fluid resuscitation recommendations based on healthcare system resources:

In Settings WITH Intensive Care (mechanical ventilation and vasoactive support available):

• Continue to recommend 10-20 mL/kg boluses
• Up to 40-60 mL/kg in the first hour
• Reassess after each bolus
• Stop if signs of fluid overload develop (hepatomegaly, rales, increased work of breathing)

In Settings WITHOUT Intensive Care:

• More cautious approach
• If NOT in shock (perfusion abnormalities only): Maintenance fluids, avoid boluses
• If IN shock (hypotension): 10-20 mL/kg boluses with extreme caution and frequent reassessment
• Lower threshold to stop fluids

Key Principle: The harm in FEAST was likely from inability to rescue patients who developed fluid overload (no ventilators available). In ICU settings with full support, fluid resuscitation remains important but must be given with continuous reassessment.

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Examiner: "A 3-year-old child with septic shock has received 60 mL/kg of fluid in the first hour and remains hypotensive. What are your next steps?"

Model Answer:

This child has fluid-refractory shock - a key turning point requiring escalation.

Immediate Actions:

1. Start vasoactive support - no further delay for fluids

   • Cold shock (prolonged CRT, cool extremities): Adrenaline 0.05-0.1 mcg/kg/min
   • Warm shock (flash CRT, warm peripheries): Noradrenaline 0.05-0.1 mcg/kg/min

2. Central venous access for vasoactive infusions and monitoring

3. Reassess for causes of refractory shock:

   • Inadequate antimicrobial coverage
   • Undrained source (abscess, empyema)
   • Pericardial effusion/tamponade
   • Adrenal insufficiency

4. Consider airway management if not already intubated

5. Stress-dose hydrocortisone if catecholamine-resistant:

   • Dose: 1-2 mg/kg q6h or 50 mg/m²/day

6. Echocardiography to assess cardiac function and guide therapy

7. Continue reassessment targeting lactate clearance, perfusion improvement

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Viva 2: Vasoactive Agent Selection in Paediatric Sepsis

Stem: "An 18-month-old child with pneumonia has progressed to septic shock despite 40 mL/kg fluid resuscitation. You need to start vasoactive support. The child has cold, mottled extremities with CRT of 5 seconds."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Examiner: "What vasoactive agent would you choose and why?"

Model Answer:

I would choose adrenaline (epinephrine) as my first-line vasoactive agent for this child.

Rationale: This child has cold shock - characterised by:

• Cold, mottled extremities
• Prolonged capillary refill time (5 seconds)

Cold shock pathophysiology:

• Low cardiac output
• High systemic vascular resistance (compensatory vasoconstriction)
• Need for inotropic support to improve cardiac output

Adrenaline Pharmacology:

• Beta-1 agonist: Increases inotropy (contractility) and chronotropy
• Beta-2 agonist: Some vasodilation at low doses
• Alpha-1 agonist: Vasoconstriction at higher doses
• Overall effect: Increases cardiac output and provides some vasoconstriction

Dosing:

• Start at 0.05-0.1 mcg/kg/min
• Titrate to clinical response (CRT, HR, BP, lactate)
• Usual range 0.05-0.5 mcg/kg/min

Why not noradrenaline first?:

• Noradrenaline is primarily an alpha-1 agonist (vasoconstriction)
• In cold shock, the child is already vasoconstricted - adding more vasoconstriction without inotropy may worsen perfusion
• However, noradrenaline can be added as a second agent if needed

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Examiner: "How do the current guidelines compare dopamine and adrenaline for paediatric septic shock?"

Model Answer:

The SSC 2020 Paediatric Guidelines now recommend against dopamine as first-line.

Dopamine Issues:

• More arrhythmogenic than adrenaline or noradrenaline
• Variable receptor activity depending on dose (dopaminergic at low dose, beta at medium, alpha at high)
• Unpredictable pharmacokinetics in children
• May cause tachyarrhythmias

Evidence:

• Adult data (De Backer 2010, PMID: 20200382) showed increased mortality with dopamine in septic shock subgroup
• Paediatric data limited but extrapolated
• SSC 2020: "We suggest using epinephrine or norepinephrine, rather than dopamine, in children with septic shock" (weak recommendation)

Current Hierarchy:

1. First-line: Adrenaline OR noradrenaline (based on shock phenotype)
2. Second-line: Add the other catecholamine
3. Third-line: Vasopressin
4. Dopamine: Reserved if other agents unavailable

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Examiner: "The child is now on adrenaline 0.3 mcg/kg/min and noradrenaline 0.2 mcg/kg/min but remains hypotensive with MAP 40 mmHg. What are your options?"

Model Answer:

This child has catecholamine-resistant shock, which carries high mortality. My approach:

Immediate Considerations:

1. Add Vasopressin:

   • Dose: 0.0003-0.002 units/kg/min
   • Acts on V1 receptors (non-catecholamine pathway)
   • Catecholamine-sparing effect
   • Particularly useful if concern for adrenal insufficiency (relative vasopressin deficiency in septic shock)

2. Stress-Dose Hydrocortisone:

   • Indicated for fluid-refractory, catecholamine-resistant shock
   • Dose: 1-2 mg/kg q6h or 50 mg/m²/day
   • May improve vasopressor responsiveness

3. Reassess for Reversible Causes:

   • Pericardial effusion/tamponade (echo)
   • Tension pneumothorax
   • Inadequate antimicrobials/undrained source
   • Adrenal insufficiency (if not already treated)

4. Consider ECMO if:

   • Refractory shock despite maximal medical therapy
   • Myocardial dysfunction on echo
   • Potentially reversible process
   • ECMO capability available

5. Family Communication:

   • Explain severity of situation
   • Discuss goals of care
   • Ensure family support present