Anaphylactic shock

Inadequate tissue perfusion, due to the failure of both the heart and the blood vessels, as a result of an extreme allergic reaction.

The allergic response causes a mixed form of shock with hypovolaemic, cardiogenic and neurogenic components. In severe cases adrenaline via an EpiPen® reverses bronchospasm, vascular permeability and vasodilation.

Read the complete article; Anaphylaxis in the Medical Library >  Pathophysiology.

Septic shock


Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection.

Septic shock is a subset of sepsis in which underlying circulatory and cellular/metabolic abnormalities are profound enough to substantially increase mortality.

Risk Factors

  • Immunocompromised
  • In-dwelling medical device (e.g. catheter, stoma, etc.)
  • History of fevers or rigors
  • Recent surgery / invasive procedure
  • Fall unrelated to mechanism of injury
  • Age > 65 years
  • Neurological symptoms: Stiff neck, headache, decreased GCS
  • Skin: Wounds, cellulitis
  • Urinary symptoms: Dysuria, frequency, odour
  • Abdominal symptoms: Pain, peritonism
  • Chest: Cough, shortness of breath


  • Respiration rate of less than 10 or greater than 22
  • SpO2 <95%
  • Systolic Blood Pressure <100mmHg
  • Pulse rate less than 50 or greater than 100
  • Temperature less than 35.5degC or greater than 38.5degC
  • Altered mental state

Neurogenic shock

Common causes of Neurogenic shock

  • Direct damage to the nervous system (spinal / head injury).
  • Poisoning e.g. drug overdose.
  • Fainting (temporary neurogenic shock).

Signs and Symptoms:

  • Patients do not present as the “typical” shocked patient, a good history of the incident is important.
  • Drop in blood pressure (major sign) - pressure may fall and then stabilise.
  • Often present with pink or flushed skin
  • Skin may be warm or cool
  • The pulse may be rapid or slow.

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