87. Definitions and causes of sepsis and trauma
What is the pathophysiology of trauma?
Acute death occurs if there is significant damage to an artery or vital organ like the heart or lungs. Pneumothorax, acute heart failure and exsanguination are common causes of death. If no acute death occurs there can still be widespread tissue injury. SIRS can develop and cause distributive shock. Reperfusion injury can occur. These factors may be enough to kill the patient in the early phase, or they can lead to MODS and sepsis, which can kill the patient later.
Bacteria in blood?
Bacteraemia is found in 50% of cases of sepsis.
SIRS is defined as having two or more of the following parameters:
Body temperature < 36℃ or >38℃ Heart rate > 90 bpm Respiratory rate > 20/min White blood cell count < 4000/µL or > 12000/µL
How can we diagnose sepsis?
By quick SOFA criteria and blood cultures
What occurs due to endothelial disfunction and and intravascular hypovolaemia?
DIC
What is the treatments for sepsis?
Empiric antibiotic treatment should begin immediately after blood cultures has been drawn; mortality increases the longer the patient goes without antibiotic therapy. The goal should be to administer antibiotics before 1 hour has passed after recognition. Any source of infection, like foreign bodies, abscesses or infected wounds should be assessed and treated appropriately. Depending on the patient's condition, fluid therapy, intubation and/or vasopressors might be necessary to maintain ventilation and circulation.
What are clinical features sepsis?
Fever Tachycardia Tachypnoea Features of organ dysfunction, depending on which organs are affected -ARDS -Hypotension -Acute renal failure, oliguria -Altered mental status -DIC
What is the symptoms of a trauma patient?
Hypotension Tachycardia Cool, moist skin with cyanosis Oliguria Apathy
Blood culture in sepsis:
If qSOFA is positive, blood cultures should be performed to look for the pathogen. The function of important organ systems should be evaluated according to the SOFA system. Blood tests should be performed to measure the following: -CBC (complete blood count) -Procalcitonin - a serum protein that increases significantly in sepsis -CRP - which signals inflammation -Lactate - which is proportional to the degree of tissue hypoxia
Gram negative and positive bacteria in sepsis:
In gram negative bacteria the LPS molecule of their cell envelope is recognized by TLR4 receptors on macrophages and other immune cells. In gram positive bacteria the cell wall is recognized by TLR2 receptors on the same cells. The immune cells will then produce inflammatory cytokines like TNF-α, IL-1, IL-6 and IL-8.
What can be the cause of SIRS?
Infectious causes Non-infectious causes: -Severe burns -Severe trauma -Circulatory shock -Pancreatitis -Vasculitis -Severe ischaemia -Severe tissue injury
Multiple trauma and polytrauma:
Multiple trauma refers to the presence of multiple independent traumas, like if one simultaneously fractures multiple bones. Polytrauma refers to the presence of multiple severe, life-threatening traumas which worsen each other, for example in a severe car crash.
What can be the causes of sepsis?
Primary infection -Pneumonia -Genitourinary infections -Gastrointestinal infections -Skin infections -Soft tissue infections Pathogens -Gram positive bacteria -Gram negative bacteria Risk factors -Age < 1 yearAge > 65 year -Comorbidities -Diabetes mellitus -Cance -Obesity -Cirrhosis -Alcoholism Immunosuppression Being in an intensive care unit Invasive medical treatment -Endotracheal tube -Intravenous lines -Urinary catheters
What criteria do sepsis have?
SOFA
Causes for multiple organ dysfunction syndrome (MODS)?
Sepsis Severe trauma Severe burns Pancreatitis Eclampsia
What is the definition of sepsis?
Sepsis is accurately defined as "A life-threatening organ dysfunction caused by a dysregulated host response to infection."
What is sepsis?
Sepsis is an acute life-threatening condition characterised by organ dysfunction caused by a dysregulated host response to infection. It's related to SIRS in pathomechanism. It has a very high mortality rate and can lead to multiple organ dysfunction syndrome (MODS) and death.
What is the definition of septic shock?
Septic shock is defined as "A subset of sepsis in which underlying circulatory and cellular or metabolic abnormalities lead to substantially increased mortality risk." As the name implies it implies the state where a person has sepsis and circulatory shock, often of the distributive type.
What are the consequences of released TNF-α, IL-1, IL-6 and IL-8?
The endothelium will become dysfunctional, allowing fluid and other molecules to cross in the interstitium. Fluid is lost to the interstitium, decreasing the oxygenation of tissues Cells will be damaged, releasing damage-associated molecular patterns (DAMP) that are recognized by immune cells and cause further inflammation
The definition of "organ dysfunction" can itself be difficult to accurately establish.
To help with this, a set of assessment criteria called "sequential organ failure assessment score" or SOFA score can help. These criteria assess the function of important organ systems like lungs, liver, CNS, kidneys, circulation and the coagulation and gives scores from 0 (normal function) to 4 (worst function). The score for each organ system is then summed up. Acute organ dysfunction is defined as an acute change in total SOFA score of 2 points or more.
What is trauma?
Trauma is a sudden insult which can have severe impact on health. Trauma is a major cause of death in all age groups; especially road traffic accidents are responsible. They can range from simple bone fractures to poles sticking through your skull. We distinguish blunt and penetrating trauma.
What is the treatment of trauma?
Treatment involves trying to maintain vital parameters. Fluid balance, electrolyte balance, oxygen supply, blood glucose and acid-base status should all be monitored and treated as necessary.
What is multiple organ dysfunction syndrome (MODS)? also called multiple organ failure (MOF)
a clinical syndrome characterised by the development of progressive and potentially reversible dysfunction in 2 or more organs or organ systems. It's often the result of acute insults like sepsis. Like in sepsis, organ dysfunction can be diagnosed by the use of the SOFA criteria, or by the use of the MODS criteria.
What is the underlying mechanism of sepsis?
a hyperinflammatory systemic reaction
What do widespread tissue ischaemia and decreased tissue oxygenation cause?
causes widespread cell injury and thereby multisystem organ dysfunction.
When is MODS considered secondary?
if it occurs as a consequence of the host's response to the insult. An example is if ARDS develops due to pancreatitis.
When is MODS considered primary?
if it occurs early after the insult and can be directly attributable to the insult itself. An example is if renal failure develops due to rhabdomyolysis.
What happens when fluid is lost to the interstitial?
intravascular hypovolaemia occurs
What is the most common primary infection that can lead to sepsis?
pneumonia, especially community-acquired pneumonia. The pathogen is more frequently gram positive than gram negative; fungal, viral or parasitic etiology is rare.
When is a person said to be in septic shock?
-The patient has sepsis, and: -Vasopressors are required to maintain a mean blood pressure of above 65 mmHg, and: -The serum level of lactate is > 2.0 mM
What is systemic inflammatory response syndrome (SIRS)?
A condition where there is widespread unregulated inflammation in the body. Pathomechanism is similar to sepsis.
What causes decreased delivery of oxygen to the tissues in septic shock?
A normal, physiological immune response requires a balance of proinflammatory and anti-inflammatory signals. In sepsis, this balance is lost. The exact mechanism that leads to the loss of this balance is not well known. Hyperactivation of the innate immune system occurs, which leads to decreased oxygen delivery to tissues.
What is quick SOFA?
A series of criteria called qSOFA (quick SOFA) can be used to quickly create suspicion about whether the patient has sepsis. qSOFA is said to be positive of 2 or more of the following criteria are present: -Altered mental status (GCS < 15) -Respiratory rate > 22 breaths per minute -Systolic blood pressure < 100 mmHg
