sepsis and multiorgan dysfunction syndrome Flashcards
definition of sepsis
life threatening organ dysfunction caused by dysregulated host response to an infection
definition of septic shock
subset of sepsis
co-existence of persistent hypotension requiring vasopressors to maintain MAP >65mmHg nad serum lactate >2mmol/L
indicates profound circulatory, cellular, and metabolic deterioration
associated with a greater risk of mortality than with sepsis alone
pathophysiology of sepsis
it is a hyperinflammatory systemic reaction
- local activation of inflammatory mediators (complement, mast cells, macrophages) = vasodilation and release of pro-inflammatory cytokines (TNF-a, IL1)
- generalised endoltelial disruption -> capillary leak -> generalised oedema (because shift of intravacular fluid and albumin into surrounding tissue)
- intravascular hypovolaemia -> excessive triggering of the extrinsic coagulation cascade -> DIC and microvascular thrombosis
- decreased oxygen utilisation adn tissue ischemia -> widespread cellular injury -> multiorgan dysfuntcion
RF for sepsis
- immunocompromise
- indwelling lines or catheters
- recent surgery or invasive procedures
- haemodialysis
- dm
- IV drug
- alcohol dependancy
- pregnancy
- breached skin integrity
causative organisms for sepsis
staph auyreus
pseudomonas species
e coli
fungal
epidemiology of sepsis
more in men
>65yrs
In 2017/18, 186,000 hospital admissions in the UK were for people with a primary diagnosis of sepsis
sx and signs of sepsis
- signs associated with specific infection eg cough
- high early warning score eg NEWS 5 or more
- tachypnoea
- high or low temp - sometimes with rigors
- tachycardia
- altered mental status
- low ox sats
- hypotension
- oliguria
- poor cap refill, mottling of the skin, ashen appearance, cyanosis
Ix for sepsis
- blood cultures
- serum lactate
- hourly UO - low - marker of AKI or intravascular volume depletion - therefore sepsis severity
- FBC - thrombocytopenia and lymphocytopenia
- UE - inc creatinine
- serum glucose
- CRP - elevated
- serum procalcitonin - elevated
- clotting screen
- LFT
- blood gas - PaCO₂ <4.3 kPa (32 mmHg) or can by hypoxaemia, hypercapnia
- ECG - ischemia, AF, or arrhythmia
LFTs in sepsis
high
- BR
- ALT
- AAT
- ALP
- and GGT
show organ dysfunction
clotting screen in sepsis
elevated PT; elevated PTT; elevated D-dimer; elevated fibrinogen
established coagulopathy with sepsis - associated with a worse prognosis
UE in sepsis
look for renal dysfunction
Patients with acute kidney injury due to sepsis have a worse prognosis than those with non-septic acute kidney injury
serum electrolytes frequently deranged;
blood urea - elevated;
creatinine - elevated
lactate in sepsis
high
marker of stress
marker of worse Px - as a reflection of the degree of stress
highlights possibility of tissue hypoperfusion
blood cultures in sepsis
take before AB - but dont delay AB for them
may be +ve for infection causing organism
definition of multiorgan dysfunction syndrome
a clinical syndrome of progressive failure of 2 or more organ systems in a critically ill patient
progressive and potentially reversible
aetiology of multiorgan system failure
inflammatory response in sepsis -> widespread tissue injury
there is apoptosis of immune, epithelial and endothelial cells and a shift to an anti-inflammatory phenotype
impaired organ perfusion because of hypotension, low CO, circulatory microthrombi, disordered microcirculation and tissue oedema
also from multiple trauma or burns
progression of multiorgan system failure
lung early and persists
CNS or liver dysfunction hours to days after sepsis onset - persists for varying lengths
sx and signs of multiorgan dysfunction
hypotension
anaemia
coagulopathy
bleeding
shock
SOFA score
used in critical care
tool to identify organ failure and predict mortality
looks at:
- PaO2/FiO2 (mm Hg)
- plts
- BR
- MAP and cardiac drugs eg adrenaline
- GCS
- creatinine
what is SIRS
systemic inflammatory response syndrome - outdated from 2016
when 2 or more of following are present:
- HR >90
- temp <36, >38
- RR >20 or PaCO2 <4.3kPa
- WCC <4000 or >12000cels/mm3 or >10% immature neutrophils
sepsis = SIRS +infection
severe sepsis = sepsis +organ dysfunction, hypotn or hypoperfusion
septic shock = sepsis induced hypotn despite adequate fluid resus
aetiology of SIRS
common inflammatory response to physiological insult - infection, ischemia, inflammation eg pancreatitis, trauma, burns
can lead to multiple organ dysfunction syndrome - altered organ function in an acutely unwell pt so that haemostasis cant be maintained w/o intervention
pathogenesis of SIRS
insult -> local cytokines = inflammatory response to fight infection adn heal
cytokines released into circulation to improve local response
acute inflammatory response usually controlled by decrease in proinflammatory mediators and release of endogenous antagonists
if haemostasis is not restored, a cycle of uncontrolled pro-inflammatory amplification occurs, with inflammation and coagulation
= microcirculatory thrombosis, hypoperfusion, ischemia, loss of circulatory integrity and tissue injury
epidemiology of SIRS
extremes of age and concomitant copnmorbidities negatively effect outcome
sx of SIRS
depends whether infectious, traumatic, ischemic or inflammatory
signs of sirs
RR sign of severity
look for vital signs, UP, mental status
Ix of SIRS
blood - FBC, UE, LFT, amylase, cardiac enzymes, CRP, ESR, IL6, IL8, procalcitonin and LPS binding protein
ABG - lactate, acidosis
cultures - blood, sputum, urine, lines, other potentially infected sites, CSF, joint fluid, ascites, pleural effusions
imaging - locate/sample source of infection
