Overview
Definition:
Septic shock in children is a life-threatening condition characterized by circulatory, cellular, and metabolic abnormalities associated with infection and a sustained threat to survival
Vasoactive infusions are crucial for restoring hemodynamic stability when fluid resuscitation alone is insufficient
Epinephrine and norepinephrine are the primary catecholamines used, each with distinct receptor profiles and clinical applications.
Epidemiology:
Sepsis is a significant cause of mortality and morbidity in pediatric intensive care units worldwide
Pediatric septic shock occurs in approximately 30-50% of children with severe sepsis
The incidence varies by geographic region and healthcare setting
Mortality rates can range from 10% to as high as 30% or more, depending on promptness of diagnosis and treatment.
Clinical Significance:
Prompt and appropriate vasoactive agent selection is critical in pediatric septic shock to achieve hemodynamic goals, improve tissue perfusion, and reduce organ dysfunction and mortality
Understanding the specific mechanisms of action, receptor affinities, and potential side effects of epinephrine and norepinephrine allows for tailored management strategies in critically ill children, making this a high-yield topic for DNB and NEET SS examinations.
Age Considerations
Neonatal Shock:
Neonatal shock may have different etiologies and responses to vasopressors
While catecholamines are used, specific considerations for immature cardiovascular systems apply
Dopamine was historically favored in neonates, but current guidelines often suggest norepinephrine as first-line if hypotension persists after fluids.
Infantile Shock:
Infants may have more labile hemodynamics
Careful titration of vasoactive agents is essential
The goal is to maintain adequate blood pressure and perfusion without causing excessive vasoconstriction or tachycardia.
Childhood Shock:
Older children generally tolerate catecholamines well, but individual responses vary
Monitoring for side effects like arrhythmias or peripheral ischemia is important
The choice between epinephrine and norepinephrine might depend on specific hemodynamic profiles and underlying shock etiologies.
Clinical Presentation
Symptoms:
Fever or hypothermia
Lethargy or irritability
Poor feeding or vomiting
Tachypnea or grunting
Decreased urine output
Delayed capillary refill
Mottled skin
Altered mental status.
Signs:
Hypotension (BP < age-adjusted 5th percentile)
Tachycardia (may be absent in severe shock)
Weak peripheral pulses
Cold extremities
Prolonged capillary refill time (> 2 seconds)
Altered level of consciousness
Decreased urine output (< 1 mL/kg/hr)
Tachypnea or respiratory distress.
Diagnostic Criteria:
According to the Surviving Sepsis Campaign guidelines, pediatric septic shock is defined by the presence of sepsis (life-threatening organ dysfunction caused by a dysregulated host response to infection) accompanied by circulatory, cellular, and metabolic abnormalities manifesting as: hypotension or need for vasopressors to maintain MAP > 65 mmHg or SBP > 5th percentile for age, and a marker of poor tissue perfusion (e.g., altered mental status, decreased capillary refill, etc.).
Diagnostic Approach
History Taking:
History of recent infection or febrile illness
Exposure to sick contacts
Underlying immunocompromise or chronic illness
Duration and progression of symptoms
Recent antibiotic use.
Physical Examination:
Assess airway, breathing, circulation (ABC)
Measure vital signs (BP, HR, RR, Temp, SpO2)
Evaluate perfusion: capillary refill time, skin temperature and color, pulses
Assess mental status
Perform a systematic head-to-toe examination to identify the source of infection.
Investigations:
Complete blood count with differential (WBC count, differential)
Blood cultures (x2 from separate sites before antibiotics)
Lactate levels (marker of tissue hypoperfusion)
Blood gas analysis (pH, PaO2, PaCO2, HCO3)
Renal function tests (BUN, creatinine)
Liver function tests
Coagulation profile (PT, PTT, INR)
Chest X-ray or other imaging to identify infection source
Urine culture.
Differential Diagnosis:
Hypovolemic shock (hemorrhage, dehydration)
Cardiogenic shock (myocarditis, congenital heart disease)
Obstructive shock (pulmonary embolism, tamponade)
Neurogenic shock
Anaphylactic shock
Adrenal insufficiency.
Management
Initial Management:
Prompt recognition and management are key
This includes aggressive fluid resuscitation (e.g., 20 mL/kg bolus of crystalloids over 5-20 minutes, repeated as needed up to 60 mL/kg in the first hour)
Oxygen therapy
Broad-spectrum antibiotics should be initiated as soon as possible, ideally within one hour of recognition, after obtaining blood cultures.
Medical Management:
When hypotension persists despite adequate fluid resuscitation, vasoactive agents are indicated
The choice depends on the hemodynamic profile and clinician preference, guided by current evidence and guidelines
**Epinephrine:** Potent alpha- and beta-adrenergic agonist
Primarily used as a second-line agent or in specific situations like anaphylactic shock or when myocardial dysfunction is suspected
It increases heart rate, contractility, and causes peripheral vasoconstriction
Dosing: Typically 0.01-0.3 mcg/kg/min IV infusion, titrate to target MAP
**Norepinephrine:** Primarily an alpha-adrenergic agonist with some beta-1 adrenergic effects
It is generally considered the first-line vasopressor in pediatric septic shock when hypotension persists after fluids and potentially a trial of dopamine or dobutamine if myocardial depression is suspected
It causes potent peripheral vasoconstriction, increasing systemic vascular resistance and blood pressure, with less chronotropic effect than epinephrine
Dosing: Typically 0.05-1 mcg/kg/min IV infusion, titrate to target MAP
Other agents: Dopamine (historical first-line, less favored now due to arrhythmias), Dobutamine (for myocardial dysfunction), Vasopressin (as adjunct).
Surgical Management:
Surgical intervention is not a primary management for septic shock itself but is crucial for source control if an identifiable surgical source of infection exists
This may include drainage of abscesses, debridement of necrotic tissue, or removal of infected foreign bodies.
Supportive Care:
Continuous hemodynamic monitoring (arterial line if available)
Central venous access for infusions
Mechanical ventilation if respiratory failure occurs
Nutritional support (enteral feeding when hemodynamically stable)
Glucose control
Renal replacement therapy if indicated
Close monitoring for signs of organ dysfunction and complications.
Complications
Early Complications:
Acute kidney injury
Respiratory distress syndrome
Disseminated intravascular coagulation (DIC)
Multi-organ dysfunction syndrome (MODS)
Hypoglycemia
Electrolyte imbalances
Arrhythmias.
Late Complications:
Post-intensive care syndrome (PICS) including neurocognitive deficits, muscle weakness, and psychological sequelae
Chronic kidney disease
Long-term respiratory issues.
Prevention Strategies:
Early recognition and aggressive management of sepsis
Prompt fluid resuscitation
Appropriate antibiotic therapy and source control
Judicious use and titration of vasoactive agents
Close monitoring of vital signs and organ perfusion
Preventing hospital-acquired infections.
Prognosis
Factors Affecting Prognosis:
Severity of illness on presentation
Time to initiation of appropriate therapy (fluids, antibiotics, vasopressors)
Presence of multi-organ dysfunction
Etiology of infection
Underlying comorbidities
Response to treatment.
Outcomes:
With timely and effective management, many children can recover from septic shock
However, mortality rates remain significant, especially in severe cases with delayed treatment or multiple organ failure
Survivors may experience long-term sequelae.
Follow Up:
Survivors of pediatric septic shock require comprehensive follow-up
This includes monitoring for neurodevelopmental deficits, growth, and psychological well-being
Regular assessments by pediatricians, subspecialists (e.g., nephrologists, pulmonologists), and allied health professionals are often necessary.
Key Points
Exam Focus:
Norepinephrine is generally the first-line vasopressor in pediatric septic shock if hypotension persists after adequate fluid resuscitation
Epinephrine is a potent alternative, particularly useful if myocardial depression is present or in specific situations like anaphylaxis
Dosing is crucial for both agents.
Clinical Pearls:
Always titrate vasoactives to achieve target Mean Arterial Pressure (MAP) or systolic blood pressure (SBP) appropriate for age, aiming for signs of improved perfusion rather than just a number
Monitor for side effects: tachycardia, arrhythmias with epinephrine
peripheral ischemia with both
Ensure secure central venous access for infusions.
Common Mistakes:
Delaying fluid resuscitation or antibiotic administration
Using vasopressors without adequate fluid volume
Inappropriate choice of vasopressor for the specific hemodynamic profile
Inadequate monitoring and titration of vasoactive infusions
Failure to consider and treat underlying sources of infection.