Shock
What are the four shock subtypes
HYPOVOLAEMIC, CARDIOGENIC, DISTRIBUTIVE, OBSTRUCTIVE
What are any of the subtypes of distributive shock?
Septic shock, anaphylaxis, neurogenic shock
Whats the mechanism of hypovolemic shock?
Loss of intravascular volume → reduced venous return (↓ preload) → reduced stroke volume → reduced cardiac output → poor tissue perfusion.
What is spinal shock?
A temporary loss of motor, sensory, reflex and autonomic function below the level of an acute spinal cord injury.
What is the definition of shock?
A state of inadequate tissue perfusion leading to insufficient oxygen delivery to cells, causing cellular dysfunction, organ failure, and potentially death.
Haemorrhagic & non-haemorrhagic shock are subtypes of which type of shock?
Hypovolaemic shock
What is mechanism of cardiogenic shoc?
Primary pump failure of the heart → inability to maintain cardiac output despite adequate volume → reduced organ perfusion.
What are the main clinical features of spinal shock?
Flaccid paralysis, areflexia, loss of sensation and reduced autonomic function below the lesion.
What are three general clinical symptoms of shock?
What is the mechanism of neurogenic shock?
Neurogenic shock occurs after disruption of sympathetic pathways, usually from a high spinal cord injury (classically above T6).
High spinal cord injury → ↓ sympathetic tone → vasodilation + venous pooling → ↓ SVR + ↓ preload → ↓ cardiac output → hypotension
What is the mechanism of distributive shock?
Widespread vasodilation and abnormal distribution of blood flow → relative hypovolaemia → reduced effective tissue perfusion.
Some forms also cause increased capillary permeability.
How does spinal shock change over time?
Initially there is flaccidity and absent reflexes. As spinal shock resolves, reflexes return and hyperreflexia and spasticity may develop.
Is spinal shock a type of haemodynamic shock?
No. Spinal shock is a neurological phenomenon, not a haemodynamic classification of shock.
Pulmonary embolism, cardiac tamponade & tension pneumothorax are subtypes of which shock?
Obstructive shock
What is the mechanism of obstructive shock?
Mechanical obstruction to blood flow into or out of the heart → reduced cardiac filling or output → poor tissue perfusion.
How is spinal shock different from neurogenic shock?
Spinal shock is a neurological loss of reflex activity, whereas neurogenic shock is a circulatory problem caused by loss of sympathetic tone, producing hypotension and often bradycardia.