What are the types of distributive shock?
- Septic shock (most common)
- Anaphylactic shock
- Neurogenic shock
What is the pathogenesis of neurogenic shock?
Damage to CNS –> loss of SANS –> hypotension, bradycardia, respiratory arrest
What is the pathogenesis of Anaphylactic shock?
Type I hypersensitivity to allergen
* Mast cells & Basophils –> histamine –> vasodilation & capillary fluid leakage
What is the pathogenesis of Septic shock?
Excessive inflammation due to disseminated infection resulting in fluid extravasation from vascular space & loss of intravascular volume
Physical obstruction of blood flow in central vessels of systemic or pulmonary circulation can lead to what type of shock?
Obstructive shock
Arrhythmias or myocardial damage that disrupt the hearts ability to maintain cardiac output can lead to what type of shock?
Cardiogenic shock
Severe fluid loss (third spacing, hemorrhage, or fluid loss) can lead to impaired tissue perfusion and cellular hypoxia and can cause irreversible organ damage in what type of shock?
Hypovolemic shock
Includes hemorrhagic shock
What is third spacing?
When fluid moves from intravascular space to interstitial fluid (third space) between cells that is non-functional
Define sepsis.
- Body temp: < 36°C or > 38°C
- HR > 90 bpm
- Tachypnea: RR > 20 bpm; PaCO2 < 32 mmHg
- WBC < 4,000/mm^3 or > 12,000/mm^3 or > 10% immature neutrophils
SIRS
What are the SIRS criteria?
3Ts w/ white sugar
* Temperature
* Tachycardia
* Tachypnea
* WBC
Define sever sepsis.
Sepsis + organ dysfunction (≥ 1 organ)
Define septic shock.
Sepsis + hypotension and hypoperfusion despite adequate fluid resuscitation
Macrophages facilitate sepsis via which molecules?
- CRP from liver
- Procalcitonin
LPS from GNBs can induce proinflammatory cytokines via stimulation of what receptor?
TLR-4
Interacts with PAMPs; IL-1, IL-6, TNF-α
Explain the procoagulant state of septic shock.
- Intravascular hypovolemia leads to triggering of extrinsic coagulation cascade
- Disseminated intravascular coagulation (DIC) and microvascular thrombosis
Describe metabolic abnormalities of septic shock.
- Pro-inflammatory cytokines suppress insulin release
- TNF-α, IL-1, glucagon drive gluconeogenesis leading to hyperglycemia
What are the pathophysiologic stages of septic shock?
- Local activation of inflammatory mediators
- Generalized endothelial dysfunction
- Procoagulation
- Metabolic abnormalities
- Organ dysfunction
- Death or survival
What molecules released by macrophages lead to leukocyte recruitment by promoting adhesion of leukocytes to endothelium and their migration through vessels?
TNF-α and IL-1
Th1 releases what molecule to stimulate macrophages?
INF-γ
