Sepsis

Key Takeaways

Sepsis is a life-threatening medical emergency caused by a dysregulated host response to infection that results in organ dysfunction. It is not synonymous with uncomplicated infection, bacteremia, or “severe infection.” For clinicians, the practical priorities are early recognition, rapid source evaluation, prompt antimicrobial therapy when indicated, frequent and ongoing hemodynamic assessment, and paying close attention to evolving organ dysfunction.  

Early symptoms are often nonspecific, and the initial presentation may include fever or hypothermia, tachycardia, tachypnea, hypotension, altered mentation, decreased urine output, mottled or clammy skin, or rising oxygen needs rather than an obvious “sepsis look.”  

Current Sepsis-3 definitions identify sepsis as suspected or documented infection plus acute organ dysfunction, commonly operationalized as an increase in SOFA (Sequential Organ Failure Assessment) score of 2 points or more; septic shock is the subset with vasopressor dependence to maintain mean arterial pressure (MAP) of 65 mmHg or greater, and serum lactate greater than 2 mmol/L despite adequate volume resuscitation. Mortality varies widely by population and severity, but septic shock remains associated with hospital mortality greater than 40% in the original Sepsis-3 framework.  

Introduction

Sepsis remains one of the most consequential syndromes in acute care because delayed recognition and treatment can rapidly lead to shock, multiple organ failure, and death. CDC describes sepsis as the body’s extreme response to an infection and emphasizes that it is a medical emergency. The World Health Organization (WHO) similarly defines sepsis as a life-threatening condition in which the body’s response to infection injures its own tissues and organs.  

Sepsis is a syndrome of infection-associated organ dysfunction, not simply a positive blood culture or a high fever. It can arise from community-acquired or healthcare-associated infection and may evolve from apparently routine presentations, including pneumonia, urinary tract infection, intra-abdominal infection, skin and soft tissue infection, or device-related infection.  

Sepsis symptoms and early signs

Early sepsis symptoms are often nonspecific, which is part of why diagnosis is frequently delayed. The CDC materials list fever, shivering or feeling very cold, shortness of breath, high heart rate or low blood pressure, clammy or sweaty skin, extreme pain or discomfort, and new confusion or disorientation among the concerning signs. Increased breathing rate and laboratory evidence of infection or organ dysfunction may be part of the diagnostic picture.  

At the bedside, the “early signs” that matter most clinically are change from baseline and evidence of emerging organ dysfunction. A patient with infection plus new confusion, rising respiratory rate, hypotension, oliguria, hypoxemia, or lactate elevation may be declaring sepsis even before shock is obvious. That is consistent with the Sepsis-3 emphasis on organ dysfunction rather than inflammation alone.  

Causes of sepsis

Sepsis is caused by infection, but the syndrome reflects the host response as much as the pathogen itself. Bacterial infections are common causes, but viral and fungal infections can also precipitate sepsis. The National Institute of General Medical Sciences (NIGMS) notes that sepsis can follow infections, serious injury, or other insults to the body, and the CDC emphasizes that any infection can lead to sepsis.  

Common clinical sources include pneumonia, urinary tract infection, intra-abdominal infection, skin and soft tissue infection, and bloodstream infection. In practice, source identification is central because management hinges on both prompt antimicrobials and source control when needed. That treatment priority aligns with Surviving Sepsis Campaign guidance for adult sepsis and septic shock.  

Classification of sepsis

Clinicians still encounter older terms such as “severe sepsis,” but the current adult consensus framework is Sepsis-3. Under Sepsis-3, sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, with organ dysfunction represented clinically by an acute increase in SOFA score of 2 points or more. Septic shock is the subset of sepsis with circulatory, cellular, and metabolic abnormalities severe enough to substantially increase mortality risk.  

This distinction matters because “infection,” “sepsis,” and “septic shock” are not interchangeable. Infection alone does not equal sepsis, sepsis requires organ dysfunction, septic shock is a more severe subgroup with persistent hypotension requiring vasopressors plus elevated lactate despite adequate resuscitation  

Sepsis criteria: SOFA, qSOFA, and SIRS

The Sepsis-3 task force recommends SOFA as the clinical construct for organ dysfunction in adults with suspected infection. An acute SOFA increase of 2 or more points is associated with increased in-hospital mortality. qSOFA (Quick Sequential Organ Failure Assessment) was introduced as a simple bedside prompt outside the intensive care unit, using altered mentation, respiratory rate 22 breaths/min or greater, and systolic blood pressure 100 mmHg or less.  

Clinically, qSOFA is best understood as a warning tool rather than a definitive diagnostic rule. A high qSOFA should heighten concern for poor outcome and trigger further evaluation, but a low qSOFA does not exclude sepsis. Likewise, SIRS criteria may still identify physiologic derangement but are no longer the defining standard for adult sepsis under Sepsis-3. 

SOFA Chart

Use SOFA to assess organ dysfunction in a patient with suspected or confirmed infection. Under Sepsis-3, an acute increase of 2 points or more supports the diagnosis of sepsis in the appropriate clinical context.  

How to use it clinically: Calculate the total SOFA score and compare it with baseline. In adults with infection, a rise of ≥ 2 points is associated with a substantial increase in in-hospital mortality risk.  

qSOFA Chart

qSOFA is a rapid bedside prompt for identifying adults with suspected infection who may be at higher risk for poor outcomes, especially outside the intensive care unit. It is not the formal definition of sepsis and should not be used to rule sepsis out. 

A qSOFA score of 2 or more should raise concern, but clinicians should still assess for organ dysfunction with SOFA and not rely on qSOFA alone as a screening or exclusion tool.  

SIRS Chart

Systemic inflammatory response syndrome (SIRS) criteria are older inflammatory-response criteria and are no longer the defining standard for adult sepsis under Sepsis-3. They remain familiar to many clinicians and may still appear in workflows, order sets, and documentation discussions.  

Traditional interpretation: 2 or more SIRS criteria suggests a systemic inflammatory response, but SIRS lacks specificity and does not by itself establish sepsis.  

Quick comparison chart 

Sepsis rash and skin findings

A rash is not required for identifying sepsis, and many septic patients will never have one. Still, skin findings can be important clues. NIGMS public-facing sepsis guidance includes skin rash among possible early symptoms, and the CDC materials highlight clammy or sweaty skin as concerning signs.  

For clinicians, the more useful concept is that skin changes may reflect either the source of infection or evolving shock physiology. Petechiae or purpura can suggest invasive meningococcal disease or disseminated intravascular coagulation, while mottling, cool extremities, or delayed capillary refill can indicate impaired perfusion.  

Risk factors for sepsis

Anyone can develop sepsis, but the CDC identifies several groups at increased risk, including adults aged 65 years and older, children younger than 1 year, people with weakened immune systems, people with chronic conditions such as diabetes or lung disease, and those with recent severe illness, surgery, or hospitalization.  

Risk stratification matters because it should lower the threshold for escalation. An older adult with pneumonia and mild confusion, a dialysis patient with fever and hypotension, or an immunocompromised patient with subtle tachypnea may be much closer to decompensation than their initial presentation suggests. That inference follows directly from the CDC’s risk framework and the Sepsis-3 emphasis on organ dysfunction.  

Mortality rate and prognosis

Mortality in sepsis is highly dependent on illness severity, source control, comorbidity burden, age, and setting, so there is no single universally applicable “sepsis mortality rate.” The WHO has reported that sepsis can lead to shock, multiple organ failure, and death, and older WHO burden estimates linked sepsis to roughly 11 million deaths globally in 2017. More recent global modeling suggests that sepsis-related deaths increased in 2020 and 2021, though methods differ across datasets.  

For clinicians, the most actionable mortality figure is often the one attached to septic shock. In the Sepsis-3 consensus work, the combination of vasopressor requirement to maintain MAP of 65 mmHg or greater plus lactate greater than 2 mmol/L despite adequate fluids was associated with hospital mortality greater than 40%.  

What clinicians should know

The first clinical reality is that sepsis is frequently missed because its early features overlap with many common presentations. Fever may be absent, leukocytosis may be absent, and the initial clue may be delirium, mild tachypnea, or unexpected hypotension. CDC’s sepsis messaging emphasizes acting fast, while Sepsis-3 emphasizes identifying organ dysfunction rather than waiting for a classic inflammatory picture.  

The second is that early management is time-sensitive. Surviving Sepsis Campaign guidance continues to prioritize rapid evaluation, prompt antimicrobials for likely sepsis or septic shock, fluid resuscitation guided by hemodynamics, vasopressors when needed, and source control. The specific pathway varies by setting, but delay worsens risk.  

The third is that documentation and coding should match the clinical picture. “Sepsis,” “severe sepsis,” and “septic shock” carry different coding implications, and documentation should clearly identify the underlying infection, organ dysfunction, and whether shock is present.  

ICD-10-CM code for sepsis

There is not one single ICD-10-CM code that covers all sepsis. In ICD-10-CM, uncomplicated sepsis is usually coded first with the underlying systemic infection code, commonly from categories such as A40.- or A41.-, depending on the organism or whether the organism is unspecified. The Centers for Medicare & Medicaid Services coding guidance states that for septic shock, the underlying systemic infection code is sequenced first, followed by R65.21 for severe sepsis with septic shock, or T81.12- for postprocedural septic shock where applicable. For severe sepsis without septic shock, R65.20 is used as an additional code after the underlying infection, along with codes for acute organ dysfunction.  

For a clinician audience, the practical pearl is that documentation should not stop at “urosepsis,” which is imprecise and often not codable as intended. Document the infection source or organism when known, state whether the patient has sepsis, specify acute organ dysfunction, and state whether septic shock is present. That improves both coding accuracy and clinical communication.  

Clinical bottom line

Sepsis is best understood as infection-associated organ dysfunction with the potential to progress rapidly to shock, multisystem failure, and death. The symptoms can be subtle early, the skin findings are variable, the diagnostic criteria are syndromic rather than pathogen-specific, and the mortality risk rises sharply once shock develops. For clinicians, the essential tasks are to recognize early warning signs, identify organ dysfunction, investigate and control the source, initiate timely therapy, and document with enough precision to support both treatment and coding.  

FAQs

What are the earliest signs of sepsis?

Early signs can include fever or hypothermia, chills, tachycardia, tachypnea, new confusion, clammy skin, hypotension, and decreased urine output. The earliest clue is often a new change from baseline in a patient with known or suspected infection rather than a dramatic presentation.  

What is the difference between sepsis and septic shock?

Sepsis is infection-associated organ dysfunction. Septic shock is a more severe subset in which the patient requires vasopressors to maintain MAP of 65 mmHg or greater and has a serum lactate greater than 2 mmol/L despite adequate fluid resuscitation.  

Is there still a classification called severe sepsis?

Clinically, Sepsis-3 moved away from the term “severe sepsis” because sepsis already implies organ dysfunction. However, “severe sepsis” still appears in ICD-10-CM coding, particularly with R65.20 and R65.21, so clinicians still encounter it in documentation and coding workflows. 

What infections most commonly lead to sepsis?

Common sources include pneumonia, urinary tract infection, intra-abdominal infection, skin and soft tissue infection, and bloodstream infection. Bacterial infections are common, but viral and fungal infections can also lead to sepsis.  

Does sepsis cause a rash?

It can, but not always. Rash is not required for diagnosis. When present, skin findings may reflect the infectious source, coagulation abnormalities, or poor perfusion rather than a single classic “sepsis rash.”  

What are the criteria clinicians should use?

Adult clinicians should think in terms of suspected or documented infection plus acute organ dysfunction. SOFA is the formal Sepsis-3 framework, while qSOFA can be a quick bedside prompt for higher-risk patients outside the intensive care unit.  

What is the mortality rate for sepsis?

There is no single mortality rate that applies to all sepsis because case mix and severity vary widely. A widely cited benchmark from Sepsis-3 is that septic shock, defined by vasopressor need plus lactate greater than 2 mmol/L after adequate fluids, is associated with hospital mortality greater than 40%.  

What ICD-10 code should clinicians document for sepsis?

There is no single universal sepsis code. The correct ICD-10-CM approach is usually to document the underlying systemic infection first and then add R65.20 for severe sepsis without septic shock or R65.21 for severe sepsis with septic shock, along with organ dysfunction codes as appropriate.  

What is the single most important thing clinicians should know about sepsis?

Sepsis is a time-sensitive syndrome of infection plus organ dysfunction, and early presentations are often subtle. Waiting for classic shock physiology can delay care; new confusion, tachypnea, hypotension, oliguria, or other acute organ dysfunction in a patient with infection should trigger immediate aggressive resuscitation and frequent reassessments.