Septic shock

Septic shock
Updated: 06/16/2022
© Jun Wang, MD, PhD

General features

  • A subset of sepsis with profound circulatory and cellular metabolism abnormalities with marked increased mortality
  • A type of distributive shock
  • Most common type of shock
  • Multiorgan failure due to dysregulated inflammatory response
  • Despite adequate fluid resuscitation
    • Persisting hypotension
    • Requiring vasopressors to maintain a mean arterial pressure of 65 mm Hg or higher
    • Serum lactate level greater than 2 mmol/L (18 mg/dL)
  • Increased risk of mortality than sepsis alone

Pathophysiology

  • Mediators
    • Microorganism factors

Bacterial components: Endotoxin, peptidoglycan, muramyl dipeptide, lipoteichoic acid, superantigens, etc

Bacterial products: Staphylococcal enterotoxin B, toxic shock syndrome toxin 1, Pseudomonas exotoxin A, M protein, etc

    • Proinflammatory mediators: TNF-alpha, Interleukin-1, granulocyte colony stimulating factor, platelet activating factor, etc
    • Complements
    • Immune cell activity regulators

Toll-like receptors

Nucleotide-oligomerization domain leucine-rich repeat protein

Caspase activation and recruitment domain helicases

  • Exaggerated systemic inflammatory type response
  • Tissue and cellular effects
    • Circulatory abnormalities
    • Immunosuppression
    • Tissue ischemia and hypoxia
    • Cytopathic injury: Direct cytotoxicity, apoptosis
  • Systemic dysfunctions
    • Coagulation: Capillary thrombosis and disseminated intravascular coagulation
    • Circulation: Pathologic vasodilation (arterial) and shunting
    • Metabolic: Insulin resistance and hyperglycemia, adrenal insufficiency (Waterhouse-Friderichsen syndrome), elevated lactate
    • Heart: Elevated cardiac output, reduced ejection fraction, reduced left ventricular stroke work index
    • Vessel: NO (Nitric Oxide) mediated dilation, impaired vasopressin secretion
    • Pulmonary: Acute lung injury, ARDS, due to vascular damage and increased permeability, alveolar edema, type II pneumocyte injury
    • Gastrointestinal: Bacterial overgrowth, ileus
    • Liver: Dysfunction
    • Kidney:  Acute kidney injury, impaired renal function due to tubular necrosis
    • Central nervous system: Encephalopathy, peripheral neuropathy

Clinical presentations

    • Fever at early phase
    • Tachypnea
    • Presentations associated with site of infection
    • Positive blood culture or clinical response to antibiotics
    • Hypotension
    • Tachycardia
    • Cool skin, decreased capillary refill, mottling, cyanosis
    • Other organ dysfunction: oliguria, acute kidney injury, altered mental status, etc

Key Laboratory findings

  • Hematology:
  • Chemistry
    • Hyperglycemia in the absence of diabetes
    • Hyperbilirubinemia
    • Hyperlactatemia
    • Elevated C-reactive protein
    • Elevated procalcitonin
  • Arterial hypoxia
  • Renal insufficiency: Oliguria, elevated creatinine
  • Adrenal insufficiency: Hyponatremia, hyperkalemia

Diagnosis

Management

    • ICU for hemodynamic monitoring
    • Supporting cardiac and respiratory functions
    • Supporting other organ systems
    • Correcting abnormal tissue perfusion
  • Treatment for infection: Antimicrobial therapy
  • Treatment of anemia and coagulopathy
  • Other support: metabolic, nutritional
  • Surgical removal of focal infections

Worse prognosis indicator

  • Overall worse prognosis
  • Delayed aggressive therapy
  • Decompensated metabolic acidosis
  • Multiorgan failure

 

 

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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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