SEPSIS

✓ Medically ReviewedDISEASEID: MDBT0056🚨 TRIAGE: EMERGENCYICD-10: A41.9

📖

Definition

CLINICAL DEFINITION

Sepsis is life-threatening organ dysfunction due to infection. Organ dysfunction means organs fail to keep the body stable. It is caused by a dysregulated host response (harmful unbalanced immune reaction) to infection. Sepsis-3 consensus (2016 international redefinition) defines sepsis by infection plus acute organ failure. Organ failure is tracked as a rise in Sequential Organ Failure Assessment (SOFA - six-organ function score) by 2 or more points.

IN PLAIN ENGLISH

Sepsis is the body failing due to a severe infection. Germs trigger a harmful overreaction of the immune system (body defence system). Organs like lungs, kidneys and brain then stop working well. It is much more serious than a simple fever or cold. It needs emergency hospital care with antibiotics and fluids.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Sepsis is not simple infection without organ failure. Fever alone does not mean sepsis. Bacteraemia (germs in blood alone) without organ failure is not sepsis. Colonisation (germs living on skin without harm) is not sepsis. Systemic inflammation without proven or suspected infection is not sepsis.

🔤

Word Breakdown

seps-

=decay or putrefaction

-is

=condition or process

Literal Meaning: decay-condition meaning putrefaction leading to systemic illness

🏷️

Abbreviations

SOFA=Sequential Organ Failure Assessment - six-system score tracking lungs, clotting, liver, circulation, brain and kidneys

qSOFA=quick SOFA - bedside screen using mental state, systolic pressure and breathing rate

NEWS2=National Early Warning Score 2 - early warning score using vital signs and oxygen need

SSC=Surviving Sepsis Campaign - international group issuing sepsis care bundles

🔄

Synonyms & Variants

Septicaemia›Blood poisoning›

🎯

Category-Specific Context

Sepsis is a Disease because it is a harmful process with organ injury. It follows infection but adds immune harm and organ failure. It spans stages from sepsis to septic shock (sepsis with deep circulation failure). Care focuses on early recognition, cause finding and organ support.

🏥

Clinical Context & Usage

CLINICAL SETTINGS

Emergency DepartmentAcute Medical UnitIntensive Care UnitGeneral WardPrimary Care for follow-up

USAGE & DOCUMENTATION NOTES

Use sepsis when infection is suspected plus new organ failure is present. Common clues are confusion, fast breathing, low pressure, low urine and high lactate. Do not use sepsis for stable local infection alone. Reassess often because early sepsis can look mild.

🔬

Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

Infection exposes phased signals called PAMPs (germ alarm molecules) and DAMPs (injured cell alarm molecules). These activate immune cells to release cytokines (immune messengers). Cytokines injure endothelium (inner vessel lining) and cause vessel leak and clotting. Leak and microclots (tiny vessel clots) reduce tissue blood flow. Poor flow plus direct cell injury causes organ failure.

PRIMARY CAUSES

Pneumonia

Infected lung releases germs and immune messengers into blood. This triggers wide immune activation and vessel leak. Low oxygen from failing lungs worsens tissue injury.

Urinary tract infection including pyelonephritis (kidney infection)

Infected urine and kidney tissue allow germs to enter blood and lymph. Bacterial toxins (germ poisons) drive fever, vessel widening and kidney stress. Blocked urine flow raises pressure and spreads infection.

Intra-abdominal infection including peritonitis and cholangitis

Leaked gut germs flood the sterile belly cavity. This causes strong local and blood-wide immune activation. Bile block or bowel hole keeps feeding germs until drained.

Bloodstream and catheter-related infection

Germs on lines or in blood spread quickly to many organs. They directly activate clotting and vessel cells. Persistent source keeps immune storm going until removed.

Skin and soft tissue infection including cellulitis and necrotising infection

Broken skin lets streptococci and staphylococci invade deep tissue. Toxins destroy tissue and overstimulate immune cells. Dead tissue acts as ongoing toxin source.

Central nervous system infection including meningitis and encephalitis

Germs in brain coverings trigger intense local swelling. Swelling raises pressure and disturbs brain function. Spill of signals into blood can drive body-wide failure.

Infective endocarditis and infected devices

Infected heart valves or implants shed germ clumps into blood. Repeated showers seed lungs, brain and kidneys. Biofilm (germ slime on devices) resists clearing until removed.

🌍

Epidemiology

Prevalence:Sepsis is common worldwide and a leading cause of hospital death. Risk is highest in infants, older adults and immunocompromised people. Cases rise with pneumonia, urinary and abdominal infections and resistant germs.

Age Group:All ages can develop sepsis. Highest danger is in newborns and infants, older adults and frail people. Chronic illness and weak immunity raise risk further.

Geographic Distribution:Sepsis occurs worldwide in all health systems. Burden is higher where pneumonia, maternal and newborn infections are common. Limited access to vaccines, clean water and timely antibiotics raises risk.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 EMERGENCY

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Septic shock with low pressure despite fluids
Meningitis with rash and neck stiffness
Necrotising soft tissue infection with severe pain out of proportion
Intra-abdominal source needing surgery
Infected line or device needing removal

URGENT EVALUATION TRIGGERS

New confusion with suspected infection
Low systolic pressure with fast heart rate
Fast breathing with low oxygen
Low urine output with fever
Mottled skin with slow refill
High lactate with infection

Contraindications & Precautions

CONTRAINDICATIONS

Do not delay antibiotics for nonurgent tests or imaging
Do not give large fluid boluses without lung and volume checks in heart failure

SPECIAL PRECAUTIONS

Monitor fluid balance closely in heart failure and kidney disease
Adjust antibiotics for kidney and liver function
Watch for allergy and Clostridioides difficile diarrhoea after broad antibiotics
Use low threshold for escalation in infants, older adults and immunocompromised people

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Septic shock
Acute respiratory distress syndrome
Acute kidney injury
Disseminated intravascular coagulation
Multi-organ failure
Secondary and hospital acquired infection
Post-sepsis physical weakness and cognitive impairment

🔀

Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Asepsis

Sounds similar but means opposite. Asepsis is absence of germs from sterile technique, not infection with organ failure.

Septicaemia

Old term often confused with sepsis. It implied germs in blood alone, while sepsis now means organ failure from unbalanced immune reaction.

Severe sepsis

Historical stage now retired. It meant sepsis with organ failure, now simply called sepsis under Sepsis-3.

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Anaphylaxis

Key Distinguishing Feature: Sudden exposure trigger with hives, swelling and wheeze that improves fast with adrenaline, cultures negative.

Cardiogenic shock

Key Distinguishing Feature: Cold clammy skin with lung crackles and raised neck veins, weak heart pump on echo, no infection source.

Hypovolaemic shock

Key Distinguishing Feature: Clear bleeding or fluid loss history with empty veins, responds to fluids alone without infection signs.

Pulmonary embolism

Key Distinguishing Feature: Sudden chest pain and breathlessness with clear lungs, clot on imaging, no fever source.

Adrenal crisis

Key Distinguishing Feature: Low sodium with high potassium and low sugar in steroid user, improves with steroids not antibiotics alone.

Acute pancreatitis

Key Distinguishing Feature: Severe upper belly pain with high lipase (pancreas enzyme) and swollen pancreas on imaging, often sterile at first.

💎

Clinical Pearls

💎

Assume sepsis in infection with new confusion, fast breathing or low pressure, even if fever is absent in older adults.

💎

Take blood cultures first but never delay antibiotics more than needed to get them.

💎

Recheck lactate, urine output and lung signs often to guide fluids and vasopressors (vessel tightening drugs).

💎

Always seek source control (drain pus, remove infected line, treat blockage) alongside drugs.

💎

After recovery, screen for weakness, kidney injury and brain fog because post-sepsis issues are common.

📝

Example Usage & SOAP

CLINICAL SENTENCE

""Older man with fever, confusion and low pressure meets sepsis criteria from suspected pneumonia.""

IN A SOAP NOTE

S: 72-year-old with cough, fever and new confusion, reduced urine. O: Temp 39.1C, HR 124, BP 86/54, RR 28, SpO2 92 percent on air, crackles right base, drowsy but rousable. Lactate high, WBC high, blood cultures taken. A: Sepsis likely from pneumonia with organ failure. P: Broad antibiotics now, fluids with lung checks, lactate recheck, chest film and urine tests, ICU review.

DIFFERENTIAL DIAGNOSIS CONTEXT

Fever with low pressure suggests sepsis, but consider mimics when source is unclear. Anaphylaxis favours exposure with hives and wheeze. Cardiogenic shock favours lung fluid and poor pump function without infection.

📊

Classifications & Scoring

GRADING SYSTEM

Sequential Organ Failure Assessment (SOFA)

Six-organ dysfunction score tracking lungs, clotting, liver, circulation, brain and kidneys. Acute rise by 2 or more points after infection marks sepsis under Sepsis-3.

SCORING TOOL

Sequential Organ Failure Assessment (SOFA)

Six-organ dysfunction score used to confirm sepsis when rise is 2 or more points after infection.

SCORING TOOL

quick SOFA (qSOFA)

Bedside screen using mental state, systolic pressure and breathing rate. Positive screen prompts urgent sepsis workup.

SCORING TOOL

National Early Warning Score 2 (NEWS2)

Track-and-trigger vital sign score using breathing, oxygen need, pressure, pulse, consciousness and temperature. Rising score prompts escalation.

📈

Prognosis

SHORT-TERM OUTCOME

Short term risk depends on speed of care and organ failure level. Early antibiotics, fluids and source control improve survival. Delay, low pressure and high lactate signal higher danger.

LONG-TERM PROGNOSIS

Survivors may face weakness, breath issues, kidney problems and memory fog. Mood changes and fatigue can last months. Follow-up and rehab help recovery after severe illness.

📚

References & Coding

ICD-10 DIAGNOSTIC CODE

A41.9

LITERATURE CITATIONS & GUIDELINES

[1]Singer et al Sepsis-3 JAMA 2016

[2]Evans et al Surviving Sepsis Campaign 2021 Crit Care Med

[3]NICE NG51 Sepsis 2017 updated

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.

SEPSIS

Definition

Word Breakdown

Abbreviations

Synonyms & Variants

Category-Specific Context

Clinical Context & Usage

Primary Causes & Pathophysiology

Epidemiology

Red Flags & Triage ★

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

URGENT EVALUATION TRIGGERS

Contraindications & Precautions

CONTRAINDICATIONS

SPECIAL PRECAUTIONS

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Confused With (LASA & DDx) ★

Clinical Pearls

Example Usage & SOAP

Classifications & Scoring

Sequential Organ Failure Assessment (SOFA)

Sequential Organ Failure Assessment (SOFA)

quick SOFA (qSOFA)

National Early Warning Score 2 (NEWS2)

Prognosis

SHORT-TERM OUTCOME

LONG-TERM PROGNOSIS

Related Terms

References & Coding