Lecture Notes on Types of Shock in Children

Definition of Shock

• Shock: Inadequate delivery of oxygen and substrate to meet metabolic demand of tissues.
• Types:
  • Compensated Shock: Occurs early; blood pressure normal; body raises heart rate to accommodate lower pressures.
  • Uncompensated Shock: Occurs later; blood pressure low; end-organ damage begins to occur.

Categories of Shock

1. Hypovolemic Shock

   • Caused by inadequate blood volume.
   • Common causes include:
     • Acute dehydration.
     • Fluid loss (e.g., diabetes insipidus).
     • Bleeding.
     • Third spacing (fluid outside of blood vessels).

2. Distributive Shock (Vasodilation)

   • Caused by conditions such as:
     • Sepsis.
     • Neurogenic shock (spinal injury).
     • Anaphylaxis (reaction causing vasodilation).

3. Cardiogenic Shock

   • Heart is primarily involved.
   • Examples include:
     • Severe cardiomyopathy.
     • Arrhythmias.

4. Obstructive Shock

   • Heart cannot effectively pump blood out.
   • Examples include:
     • Cardiac tamponade.
     • Pulmonary embolism.
     • Tension pneumothorax.

Clinical Presentation of Shock

• Common Signs:

  • Fever (especially in septic shock).
  • Tachycardia (or bradycardia in newborns).
  • Low blood pressure (normal in compensated shock).
  • Increased respiratory rate (to correct metabolic acidosis).
  • Altered mental status (due to end-organ damage).
  • Delayed capillary refill.
  • Decreased peripheral pulses.

• Assessment Techniques:

  • Capillary refill should be assessed centrally (e.g., over the glabella) if extremities are cold.

Clinical Context and Labs

• Importance of understanding clinical context (e.g., febrile pneumonia vs. trauma).
• Key Labs to Consider:
  • Chem-7 and Blood Gas:
    • Sodium abnormalities indicate dehydration (hyper/hyponatremia).
    • Potassium levels (risk of cardiac arrhythmia).
    • Acidosis reveals metabolic acidosis; blood gas helps assess respiratory compensation.
  • BUN and Creatinine:
    • Elevated in prerenal hypovolemia or intrarenal end-organ damage.
    • Typically, BUN is elevated while creatinine is normal in prerenal; both elevated in intrarenal.
  • Liver Function Tests:
    • Look for elevated ALT and AST in severe shock (indicates liver hypoperfusion).
  • EKG and Echo:
    • Important for assessing cardiogenic shock causes.
  • Chest X-Ray:
    • Useful for identifying obstructive shock (e.g., pericardial effusion, tension pneumothorax).

Summary

• Understanding the types and causes of shock in children is essential for appropriate assessment and management.