140 - Collapse Flashcards
What does SIRS stand for and what are the symptoms?
Severe Inflammatory Response Syndrome
Increased HR, Incr. RR, Incr. or decr. Temp, Incr. or decr. WCC
what can cause maldistributive shock?
vasodilation, anaphalaxis, sepsis, spinal shock
what mechanisms cause SIRS?
cytokine storm, complement activation, coagulation cascade activation, hypotension (due to NO & microvascular damage), neuro-endocrine disturbance
How is sepsis defined?
SIRS + confirmed infection (by blood cultures or radiologically)
how is severe sepsis defined?
Sepsis + hypoperfusion + hypotension (systolic BP < 90mmHg) + organ dysfunction
How is septic shock defined?
severe sepsis with refactory hypotension (resistant to adequate fluid resuscitation)
what are the symptoms of sepsis?
incr. or decr. temp (>38C or 20 or PaCO290 bpm), leukocytosis (WBC >12000/microL or <4000/mircoL), hypoxaemia, altered mental state, raised CRP
what are some of the effects of sepsis on the systems of the body?
CNS - encephalopathy, RS - acute resp. distress syndrome, CVS - hypotension & capillary leak, GI - leak of bacteria into blood, GU - acute tubular necrosis & renal failure, haematology - disseminated intravascular coagulation (DIC) & platelet & WBC deficiencies, Endocrine - failure of hypopituitary adrenal axis (steroid defficiency)
what is the pathophysiology of sepsis?
1) innate immunity initiates response - Pathogen Assoc. Molecular Patterns (PAMPS) and Toll Like Receptors (TLR)
2) acute inflammation - cytokines & hormones cause vasodilation, cell recruitment, fever, pain. Tissue damage caused by neuts, macro,NK,clotting
3) Adaptive amplification of inflammation - T&B cells + antibodies
4) Immunosuppression & apoptosis of WBCs & tissue cells due to cytokines -organ dysfunction & further inflammation
5) Sepsis and widespread organ dysfunction due to DIC, cytokines, vasodilation & hypoperfusion
what gram +ve organisms (55%) cause sepsis?
streptococcus via soft tissue infection and Staphylococcus via wounds, bone infection. Both release exotoxins which can cause toxic shock syndrome
what gram -ve organisms (40%) cause sepsis?
lipids (endotoxin) organisms such as E Coli, pseudomonas, proteus, kliebsiella
how would you manage sepsis?
ABCDE, O2 (15L/min), fluids (hartmans or saline at least 1.5L or 20ml/kg in shock), ABX (blood cultures before or empirical), remove IV lines, take bloods (MC&S, FBC, CRP, ABGs), monitor (urine output, temp, sats,RR,BP,PR), ECG, radiology
what causes anaphylaxis?
Type 1 Hypersensitivity Reaction
Prior sensitisation of mast cells to antigen (bonding of IgE to mast cell). Then cross linking of antigen with mast cell bound IgE which causes degranulation later.
how does sensitisation occur?
dendritic cell picks up antigen > activates Th2 cell > activates B cell to produce IgE antibody > binds to Fc receptor on mast cells > mast cell is primed
how does the hypersensitivity reaction occur?
Antigen is experienced again > cross links with mast cell bound IgE > degranulation occurs releasing histamines, proteases, chemotactic factors > muscle spasms, vascular dilation and incr. permeability (oedema), mucous secretion and tissue damage.
