PANCE Blueprint Infectious Disease (6%)

Sepsis/systemic inflammatory response syndrome (Lecture)

Patient will present as → a patient with severe pancreatitis is experiencing new-onset changes in mental status. Vitals are BP 70/50 mm Hg, HR 132/min, RR 24/min, temp 103°F, sat 94%. Laboratory values reveal a WBC count of 28,000 and a serum lactate level of 17.3 mmol/L (normal: 0.5–2.2 mmol/L).

What are the components of the qSOFA (Quick SOFA) Score for Sepsis?

Quick SOFA – Use to predict mortality, NOT to diagnose sepsis

  • New or worsened mentation
  • Respiratory rate greater than or equal to 22/min
  • Systolic blood pressure less than or equal to 100 mmHg

SEPSIS 3 Guidelines

Sepsis is now defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection

Septic shock is defined as sepsis with circulatory, cellular, and metabolic dysfunction that is associated with a higher risk of mortality

  • Previously, septic shock was identified by the presence of hypotension. It is now recognized that hypotension can be a late manifestation, and tissue hypoperfusion proceeds hypotension
  • Lactate level is an indirect marker of tissue perfusion

Etiology: Respiratory, gastrointestinal, genitourinary, and skin and soft tissue infections are the most common sources

  • Pneumonia is the most common cause of sepsis
  • Fever is the most common manifestation, however, an absence of fever does not exclude sepsis

SIRS Criteria: The systemic inflammatory response syndrome (SIRS) criteria are no longer part of the new sepsis guidelines (Sepsis-3). However, still have a role in the identification of acute infections

  • Systemic inflammatory response syndrome (SIRS) requires at least 2 of the 4 following criteria be met (no longer used, important to be aware of)
    • Body temperature less than 36 deg C or greater than 38 deg C
    • HR > 90 bpm
    • Respiratory rate greater than 20/min
    • WBC count less than 4,000 or greater than 12,000 OR greater than 10% bands

The two most commonly used scores are the quick Sequential (Sepsis-related) Organ Failure Assessment score (qSOFA) score and the National Early Warning Score (NEWS) score.

Quick SOFA (qSOFA) and SOFA - replaced the SIRS scoring system. Use to predict mortality, NOT to diagnose sepsis, per Surviving Sepsis Guidelines ⇒ qSOFA is used outside ICU, while the full SOFA is used in the ICU.

  • Sepsis should be suspected in patients meeting at least two of the following three qSOFA criteria
    • New or worsened mentation
    • Respiratory rate greater than or equal to 22/min
    • Systolic blood pressure less than or equal to 100 mmHg

NEWS is an aggregate scoring system derived from six physiologic parameters

    • Respiration rate
    • Oxygen saturation
    • Systolic blood pressure
    • Pulse rate
    • Level of consciousness or new confusion
    • Temperature

The aggregate score represents the risk of death from sepsis and indicates the urgency of the response:

  • 0 to 4 – low risk (a score of 3 in any individual parameter is low-medium)
  • 5 to 6 – medium risk
  • 7 or more – high risk

Gram-positive shock results from exotoxins leading to fluid loss - common etiologies are staph and strep

Gram-negative shock is caused by endotoxin by bacteria - such as E. Coli, Klebsiella, Proteus, Pseudomonas

Group associations:

  • Neonates: Group B Strep, E. coli, Klebsiella
  • Children: H. influenzae, pneumococcus, meningococcus
  • Adults: Gram-positive cocci, aerobic bacilli, anaerobes
  • IV drug: users S. aureus
  • Asplenic patients: Pneumococcus, H. influenzae, meningococcus
  • Line-associated infections: Skin flora (e.g., coagulase-negative staph)

Initial evaluation of patients with suspected sepsis includes basic laboratory tests, cultures, imaging studies as indicated, and sepsis biomarkers such as procalcitonin and lactate levels

  • CBC with diff; BMP; LFTs; urinalysis
    • Neutropenia or neutrophilia with increased bands
    • Thrombocytopenia occurs in 50% of the cases
  • Sepsis biomarkers lactate and procalcitonin
    • Procalcitonin levels rise within four hours after the onset of infection and peak at 12-48 hours
    • Lactate levels rise secondary to tissue hypoxia ⇒ levels > 18 are diagnostic of septic shock
  • Arterial or venous blood sampling can determine the degree of acid-base abnormalities
    • Respiratory alkalosis with a metabolic acidosis 
  • Two sets of peripheral blood cultures including a set from the central venous catheter, as well as cultures of urine, stool, sputum, and skin and soft tissue
  • CSF, joint, or pleural, and peritoneal fluid cultures as needed
  • Coagulation studies and +/- DIC panel
  • Imaging should include CXR, with additional studies as indicated

Any neonate with a temperature of 100.4 deg F or higher should receive a full workup:

  • Blood and urine culture, UA, CBC, LP

Identify and remove the cause of infection - patients often require ICU admission

  • Fluid resuscitation is the priority in early management, including administering an IV crystalloid at 30 mL per kg within the first three hours
  • Empiric antibiotics within one hour
  • Vasopressor therapy is indicated if hypotension persists despite fluid administration
    • Norepinephrine is the first-line vasopressor agent for patients if initial fluid resuscitation fails to restore MAP to > 65 mm HG
  • Send blood cultures (draw blood cultures before initiating antibiotics)
  • Remove all existing catheters, IV lines, central lines

Picmonic
Sepsis and Septic Shock

Sepsis is a systemic inflammatory response to an infection and it is classified as severe sepsis when organ dysfunction is involved. Septic shock is the occurrence of sepsis with hypotension despite adequate fluid resuscitation. In response, several pathological mechanisms occur in the body including excessive vasodilation, increased microvascular permeability, excessive cellular activation, and increased coagulation. This results in the maldistribution of blood leading to inadequate tissue perfusion and subsequently tissue hypoxia.

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Sepsis Assessment

Sepsis is a systemic infection that triggers a systemic inflammatory response syndrome (SIRS) in the body in response to toxins. The initiating event may result from an infection, major surgery, trauma, burns, or acute pancreatitis. Common symptoms include fever, hypotension from systemic vasodilation, an increase in white blood cell count, change in LOC, tachycardia, and tachypnea. Some patients may also present with significant edema due to fluid shift, along with elevated blood glucose levels. Factors placing the patient at increased risk for developing this condition include increased aged, immunosuppressed individuals, and prolonged hospitalization.

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DIC

DIC is a secondary disease that results from the abnormal widespread over-activation of the coagulation cascade (either the intrinsic or extrinsic pathway). This results in thrombi formation in the microcirculation and subsequent tissue hypoxia and infarction and microangiopathic hemolytic anemia.

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Types of Shock

Shock is a condition characterized by decreased tissue perfusion and impaired cellular metabolism. The four main types of shock classified by either the functional impairment or the site of origin and are known as hypovolemic, cardiogenic, obstructive, and distributive. More than one type of shock can be present at the same time.

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Question 1
Which one of the following infections is the most common cause of sepsis overall? (check one)
A
Genitourinary tract infection
Hint:
See D for explanation
B
Infection-related to an indwelling device
Hint:
Skin and soft tissue infection
C
Skin and soft tissue infection
Hint:
Skin and soft tissue infection
D
Pneumonia
Question 1 Explanation: 
Respiratory, gastrointestinal, genitourinary, and skin and soft tissue infections are the most common sources of sepsis. Pneumonia is the most common cause of sepsis overall
Question 2
Based on current guidelines, which one of the following statements about intravenous fluid administration in patients with sepsis-related hypotension is correct?
A
Albumin is the fluid of choice, if available
Hint:
See B for explanation
B
30 mL per kg of an intravenous crystalloid, such as saline, should be administered within the first three hours of presentation
C
A 1-L bolus of saline should be administered every hour until blood pressure normalizes
Hint:
See B for explanation
D
Administration of vasopressor therapy via peripheral administration is preferred over a central venous catheter
Hint:
See B for explanation
Question 2 Explanation: 
Fluid resuscitation is the priority in early management, including administering and IV crystalloid at 30 mL per kg within the first three hours.
Question 3
You have been caring for a patient with sepsis and hypotension in the emergency department. Following the administration of the recommended amounts of intravenous fluid, the patient’s mean arterial pressure remains below the target level of 65 mm Hg or greater. Which one of the following vasopressor therapies should be used first to increase the patient’s mean arterial pressure?
A
Epinephrine
Hint:
See B for explanation
B
Norepinephrine
C
Vasopressin
Hint:
See B for explanation
D
Vasopressin plus epinephrine
Hint:
See B for explanation
Question 3 Explanation: 
Vasopressor therapy is indicated if hypotension persists despite fluid administration. Norepinephrine is the first-line vasopressor agent for patients with septic shock if initial fluid resuscitation fails to restore mean arterial pressure to 65 mm Hg or greater. Norepinephrine should be initiated at 2 to 5 mcg per minute and titrated up to 35 to 90 mcg per minute to achieve a mean arterial pressure of 65 mm Hg or greater. If norepinephrine fails to restore the mean arterial pressure to this level, vasopressin (up to 0.03 units per minute) can be added as a second-line agent, followed by the addition of epinephrine (20 to 50 mcg per minute) if needed.
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References: Merck Manual · UpToDate

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