Sepsis Diagnosis and Management

Diagnostic Criteria

The Society of Critical Care Medicine recommends that sepsis be characterized by a systemic inflammatory response to infection with specific diagnostic criteria including fever or hypothermia, tachycardia, tachypnea, altered mental status, and evidence of organ dysfunction 1, 2
Fever is defined as a core temperature >38.3°C or hypothermia as a core temperature <36°C 1
Tachycardia is defined as a heart rate >90 beats per minute or >2 standard deviations above normal for age 1
Tachypnea is defined as a respiratory rate >20 breaths per minute 1, 3
Significant edema or positive fluid balance is defined as >20 mL/kg over 24h 1
Hyperglycemia is defined as a plasma glucose >140 mg/dL in the absence of diabetes 1
Leukocytosis is defined as a WBC >12,000/μL or leukopenia as a WBC <4,000/μL 1
Normal WBC count with >10% immature forms is also a diagnostic criterion 1
Elevated plasma C-reactive protein or procalcitonin is defined as >2 standard deviations above normal 1
Arterial hypotension is defined as SBP <90 mmHg, MAP <70 mmHg, or SBP decrease >40 mmHg in adults 1, 3
Mixed venous oxygen saturation >70% is a diagnostic criterion 4
Cardiac index >3.5 L/min/m² is a diagnostic criterion 4
Arterial hypoxemia is defined as PaO₂/FiO₂ <300 1, 3
Acute oliguria is defined as urine output <0.5 mL/kg/h for at least 2h despite adequate fluid resuscitation 1, 3
Creatinine increase ≥0.5 mg/dL is a diagnostic criterion 1
Coagulation abnormalities are defined as INR >1.5 or aPTT >60s 1
Ileus is defined as absent bowel sounds 1
Thrombocytopenia is defined as a platelet count <100,000/μL 1
Hyperbilirubinemia is defined as plasma total bilirubin >4 mg/dL 1
Hyperlactatemia is defined as >1 mmol/L 1
Decreased capillary refill or skin mottling is a diagnostic criterion 1, 3
Peripheral cyanosis is a diagnostic criterion 3, 5

Severe Sepsis and Septic Shock

Severe sepsis is defined as sepsis with evidence of organ dysfunction or tissue hypoperfusion 1, 3
Septic shock is defined as severe sepsis with persistent hypotension despite adequate fluid resuscitation and evidence of tissue hypoperfusion 3, 6
Sepsis-induced hypotension is a diagnostic criterion for severe sepsis 1, 3
Lactate above upper limits of normal is a diagnostic criterion for severe sepsis 1
Urine output <0.5 mL/kg/h for >2h despite adequate fluid resuscitation is a diagnostic criterion for severe sepsis 1
Acute lung injury with PaO₂/FiO₂ <250 (in absence of pneumonia) or <200 (with pneumonia) is a diagnostic criterion for severe sepsis 1
Creatinine >2.0 mg/dL is a diagnostic criterion for severe sepsis 1
Bilirubin >2 mg/dL is a diagnostic criterion for severe sepsis 1
Platelet count <100,000/μL is a diagnostic criterion for severe sepsis 1
Coagulopathy (INR >1.5) is a diagnostic criterion for severe sepsis 1

Management of Sepsis

Prompt fluid resuscitation with crystalloid solutions (at least 20 mL/kg initially) is recommended 3
Target a positive response to fluid loading: >10% increase in systolic/mean arterial pressure, >10% reduction in heart rate, and/or improvement in mental status, peripheral perfusion, and urine output 5
Early administration of appropriate antibiotics is crucial for reducing mortality 7
Identify and control the source of infection promptly 7
Norepinephrine is the first-line vasopressor for hypotension unresponsive to fluid resuscitation 7
Regular assessment of vital signs, mental status, urine output, and peripheral perfusion is recommended 3

Special Considerations

White blood cell count cannot be used as a criterion to define sepsis in neutropenic patients 8, 6
Main risk factors for sepsis in neutropenic patients include severity and duration of granulocytopenia, disruption of skin and mucosal barriers, and malnutrition 6
Clinical diagnosis supported by basic laboratory tests like complete blood count is recommended in resource-limited settings 7
Ultrasound can be a cost-effective diagnostic tool when CT is unavailable 7
Adapt fluid resuscitation protocols based on available monitoring capabilities 5

Sepsis Diagnosis and Treatment Guidelines

Diagnostic Criteria and Initial Management

The Society of Critical Care Medicine recommends administering effective IV antimicrobials within the first hour of recognizing septic shock or severe sepsis, with a strong recommendation and high-quality evidence 9, 10, 11
The European Society of Intensive Care Medicine suggests obtaining at least 2 sets of blood cultures (aerobic and anaerobic bottles) before antimicrobials, and drawing at least 1 percutaneously and 1 through each vascular access device (unless device inserted <48 hours ago) 9
Elevated lactate levels (>1 mmol/L) indicate tissue hypoperfusion, according to the Society of Critical Care Medicine 12, 9, 10

Treatment Protocol

The Society of Critical Care Medicine recommends giving at least 30 mL/kg IV crystalloid within the first 3 hours for sepsis-induced hypoperfusion, with a strong recommendation despite low-quality evidence 9
The European Society of Intensive Care Medicine suggests targeting a mean arterial pressure ≥65 mmHg in patients requiring vasopressors, with a strong recommendation and moderate-quality evidence 9, 10
Guide resuscitation to normalize lactate in patients with elevated levels as a marker of tissue hypoperfusion, according to the Society of Critical Care Medicine 9, 10, 12

Screening and Performance Improvement

Hospital systems should implement routine sepsis screening for acutely ill, high-risk patients, and maintain performance improvement programs for sepsis management, according to the European Society of Intensive Care Medicine 9, 10, 11

Sepsis Diagnosis and Management

Diagnostic Criteria

The diagnosis of sepsis requires suspected or documented infection plus evidence of organ dysfunction, operationalized by a NEWS2 score of 5 or higher, according to the British Medical Journal guidelines 13
A NEWS2 score of 7 or higher indicates high risk, prompting sepsis diagnosis and treatment within 1 hour, as recommended by the British Medical Journal 13
A NEWS2 score of 5-6 indicates moderate risk, prompting sepsis diagnosis and treatment within 3 hours, according to the British Medical Journal guidelines 13
Critical override criteria, such as mottled or ashen appearance, non-blanching petechial or purpuric rash, or cyanosis of skin, lips, or tongue, warrant immediate sepsis diagnosis regardless of NEWS2 score, as stated in the British Medical Journal 13
The Glasgow Coma Scale can be used to assess neurological dysfunction, with a score of 13 or less indicating altered mental status, as reported in the World Journal of Emergency Surgery 14

Special Populations

Elderly patients may present with attenuated inflammatory response and fewer peritoneal signs, requiring modified interpretation, according to the World Journal of Emergency Surgery 14
HIV patients have increased susceptibility and altered immune responses, necessitating special consideration, as reported in the World Journal of Emergency Surgery 14

Timing of Re-evaluation

High-risk patients (NEWS2 ≥7) should be re-evaluated every 30 minutes, according to the British Medical Journal guidelines 13
Moderate-risk patients (NEWS2 5-6) should be re-evaluated every hour, as recommended by the British Medical Journal 13
Low-risk patients (NEWS2 1-4) should be re-evaluated every 4-6 hours, according to the British Medical Journal guidelines 13

Immediate Actions

Lactate should be measured immediately upon sepsis diagnosis, as reported in the World Journal of Emergency Surgery 14
IV antibiotics should be administered within 1 hour for high-risk patients, 3 hours for moderate-risk patients, or 6 hours for low-risk patients, according to the British Medical Journal guidelines 13

Sepsis Diagnosis and Management

Definition and Clinical Recognition

The Society of Critical Care Medicine defines sepsis as requiring both documented or suspected infection AND evidence of organ dysfunction, which inherently produces observable clinical signs 15
The transition from simple infection to sepsis occurs when the inflammatory response causes organ dysfunction that produces clinical signs, as defined by the World Journal of Emergency Surgery 15, 16
The 2016 Surviving Sepsis Campaign explicitly defines sepsis as requiring both infection AND organ dysfunction, operationalized through scoring systems like SOFA or NEWS2, as recommended by the BMJ 15, 17

Clinical Implications and Treatment

The goal is to identify patients with infection who are at high risk of progressing to sepsis before irreversible organ damage occurs, and routine screening of high-risk infected patients is recommended to detect early organ dysfunction 15
Immediate treatment upon recognition is crucial because sepsis is a medical emergency, and administration of antibiotics within 1 hour of sepsis diagnosis is recommended, as stated by the BMJ 15, 17
Aggressive fluid resuscitation (30 mL/kg within 3 hours) is recommended once sepsis is identified, as per the Critical Care Medicine guidelines 15
The 2024 NICE guidelines reinforce the importance of stratifying treatment urgency based on NEWS2 scores, with high-risk patients requiring antibiotics within 1 hour, as published in the BMJ 17, 18

Septic Shock Diagnosis and Immediate Management in Adults

Diagnostic Criteria

Persistent hypotension with a mean arterial pressure < 65 mmHg defines hemodynamic compromise in septic shock. [19][20]
An elevated serum lactate level > 1 mmol/L indicates tissue hypoperfusion and supports the diagnosis of septic shock. [19][20]

Immediate Therapeutic Interventions

Antimicrobial Therapy

Initiate broad‑spectrum intravenous antibiotics within 1 hour of recognizing septic shock; each hour of delay reduces survival by approximately 7.6 %. [21][19]20

Fluid Resuscitation

Administer an initial crystalloid bolus of 30 mL/kg within the first 3 hours of presentation. 20

Vasopressor Support

If MAP remains < 65 mmHg after the initial fluid bolus, start norepinephrine immediately to achieve MAP ≥ 65 mmHg. [19][20]

Diagnostic Workup (Within 1 Hour)

Microbiologic Cultures

Obtain at least two sets of blood cultures (aerobic and anaerobic) before antibiotics; draw one set percutaneously and a second set through any indwelling vascular device. [19][20]
Collect urine for culture when a urinary source is suspected. 22
Obtain sputum cultures if respiratory symptoms are present. 21
Perform wound or skin lesion cultures for suspected soft‑tissue infection. 23

Laboratory Markers

Measure serum procalcitonin and C‑reactive protein; values > 2 standard deviations above normal support a bacterial etiology. 22

Imaging Studies

Perform a chest X‑ray immediately to evaluate for pneumonia or other thoracic sources. 19
Use abdominal ultrasound or CT when intra‑abdominal infection is suspected. 19
Bedside point‑of‑care ultrasound can be employed to limit patient transport. 19

Common Infectious Sources in Young Adults

Pneumonia/respiratory tract infection is the most frequent source of septic shock in this age group; obtain chest imaging promptly. [19][21]
Intra‑abdominal infections (e.g., appendicitis, cholecystitis, peritonitis) should be evaluated with abdominal imaging. [19][23]
Urinary tract infection/pyelonephritis warrants urinalysis and urine culture. [21][22]
Bloodstream infection from any focus requires timely blood cultures. [19][22]
Meningitis or CNS infection: assess for meningeal signs and perform lumbar puncture if no contraindications (e.g., elevated ICP, coagulopathy). [23][24]
Soft‑tissue/skin infections (e.g., cellulitis, necrotizing fasciitis) should be inspected for typical signs and cultured if needed. 23

Less Common but Important Sources

Endocarditis – obtain multiple blood cultures and consider echocardiography when suspicion is high. [22][19]
Tuberculosis – consider in prolonged fever without an obvious source, especially in endemic settings. 21
Invasive candidiasis – evaluate with 1,3‑β‑D‑glucan assay and mannan/anti‑mannan antibodies in immunocompromised patients. 19

Critical Pitfalls to Avoid

Do not delay antibiotics: each hour of postponement lowers survival by ~7.6 %. 21
Do not wait for culture results before starting antibiotics; the delay should not exceed 45 minutes after cultures are drawn. [19][20]
Do not under‑resuscitate: ensure the full 30 mL/kg crystalloid is given within the first 3 hours. 20
Do not postpone vasopressors: initiate norepinephrine promptly if MAP remains <65 mmHg after fluids. [19][20]
Do not overlook occult infection sites: systematically examine for hidden sources such as perineal abscesses, retained foreign bodies, or pressure ulcers. 23

Evidence‑Based Management of Sepsis with Recurrent Cellulitis

Antimicrobial Therapy

Empiric addition of vancomycin is recommended for patients with recurrent cellulitis because of the high risk of MRSA colonization or infection. 25
When peripheral vascular access is unavailable, intra‑osseous access or intramuscular ceftriaxone or ertapenem should be used to avoid delaying the first dose of antibiotics. 25

Fluid Resuscitation

Administer 30 mL/kg of isotonic crystalloid (normal saline or lactated Ringer’s) within the first 3 hours of sepsis recognition to treat hypoperfusion. 25
Crystalloids are preferred over colloids because colloids are associated with higher rates of renal failure and mortality. 26
Albumin should not be used for initial resuscitation, as it provides no survival benefit. 26

Vasopressor Support

If the mean arterial pressure (MAP) remains < 65 mmHg after the initial crystalloid bolus, start norepinephrine immediately, titrating 0.1–1.3 µg/kg/min to achieve target MAP. 26
Dopamine is not recommended; norepinephrine has superior efficacy and safety. 26

Lactate Monitoring

An elevated lactate > 1 mmol/L identifies tissue hypoperfusion and defines severe sepsis, guiding the need for aggressive resuscitation. 25

Bicarbonate Therapy for Lactic Acidosis

Do not give sodium bicarbonate when arterial pH is ≥ 7.15, even in the presence of lactic acidosis. 27
Two randomized controlled trials found no hemodynamic improvement or reduction in vasopressor requirements with bicarbonate therapy. 27
Bicarbonate administration can cause sodium and fluid overload, raise lactate and PaCO₂, and lower ionized calcium. 27
The effect of bicarbonate when pH is < 7.15 remains uncertain; current guidance favors avoidance. 27

Source‑Control Considerations

Immunocompromise (e.g., HIV, diabetes, malignancy, immunosuppressive drugs) is a recognized risk factor for recurrent cellulitis and should prompt a thorough search for occult infection sources. 26

Antibiotic De‑escalation

Narrow the antimicrobial spectrum once the causative pathogen and susceptibilities are identified, typically after 48–72 hours of therapy. 25
Discontinue vancomycin if MRSA is ruled out by culture or molecular testing. 25
Transition to targeted therapy based on definitive culture results. 25

MRSA Colonization Screening

Perform MRSA colonization screening in patients with recurrent cellulitis and consider decolonization protocols when colonization is detected. 25