Shock

Shock
Updated: 08/08/2022
© Jun Wang, MD, PhD

General features
  • Cell/tissue hypoxia
  • Due to circulatory failure
  • Life threatening
  • Reversible at early stage only
  • Need to initiate therapy immediately while rapidly identify underlying etiology
  • Treat underlying etiology
Stages
  • Compensation: Perfusion of vital organs maintained
  • Decompensation: Hypoperfusion and lactic acidosis
  • Irreversible: Permanent cell/tissue damage, organ failure, usually leads to death
Classification
  • Distributive: Relative hypovolemia due to pathological redistribution of intravascular volume, usually resulted from excessive vasodilation
  • Cardiogenic: Cardiac malfunctioning associated critical reduction of pumping capacity
    • Cardiomyopathic
    • Arrhythmic
    • Mechanical
  • Hypovolemic: Absolute hypovolemia due to loss of intravascular volume, usually acute
    • Hemorrhagic
    • Non-hemorrhagic
  • Obstructive: Reduced cardiac pumping capacity due to obstruction of large vessels or heart
    • Pulmonary vascular
    • Mechanical
  • Combined
Key pathogenesis
  • Reduced oxygen delivery
  • Inadequate oxygen utilization
  • Increased oxygen consumption
  • Mixed
Pathophysiology

Clinical presentations
  • Hypotension
  • Tachycarcia
  • Tachypnia
  • Cool clammy skin
  • Change of mental status
  • Oliguria
Ancillary exam findings
  • Laboratory tests
    • Metabolic acidosis
    • Hyperlactatemia
    • Impaired renal/liver function
    • Etiology associated findings (CBC, coagulation, etc)
  • Radiologic findings (depending on underlying causes)
    • Chest: pneumonia, ARDS, widened mediastinum, etc
    • Abdomen: intestinal obstruction, etc
    • Head: trauma, hemorrhage, etc
  • EKG
    • Cardiac ischemia/infarct
    • Arrhythmia
    • Pulmonary embolism, etc
Diagnostic approaches
  • Always suspected in patients with hypotension, hyperlactatemia and tachycardia
  • Based on clinical and laboratory findings
Diagnosis
  • Diagnosed based on clinical evaluation and lab results
  • Evidences of hypoperfusion
    • Change of mental status 
    • Oliguria 
    • Peripheral cyanosis
  • Signs of compensatory mechanisms: Tachycardia, tachypnea, hypotension, etc
  • Laboratory findings 
    • Elevated blood lactate 
    • Reduced PaCO2
Initial management approaches
  • Assess airway, breathing and circulation
  • Lifesaving intervention if needed
  • Etiology identification based on history, PE, ancillary tests
  • Hemodynamic support
Practice questions

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Contents

Pathology notes Jun Wang, MD, PhD 1. General information Frequently discussed syndromes Terms of dermatology Terms of hematology 2. Primary immunodeficiency disorders 3. Hemodynamic abnormalities Shock Thrombosis and embolism Bleeding disorders 4.  Benign blood cell disorders Anemia Benign white cell disorders 5. Hematopoietic neoplasms Lymphoid neoplasms Myeloid neoplasms Histiocytic neoplasms: Langerhans cell histiocytosis 6. Cardiovascular system Pulmonary hypertension Cardiovascular system tumors 7. Respiratory tract tumors 8. Gastrointestinal tract Congenital disorders Infectious gastroenteritis Oral cavity Esophagus Stomach Intestinal tumors Salivary glands Exocrine pancreas and gallbladder 9. Urinary system Kidney masses Lower urinary tract 10. Male reproductive system 11. Female genital tract 12. Breast 13. Endocrine organs Pituitary gland Adrenal gland Thyroid gland Parathyroid gland Endocrine pancreas...
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