Sepsis

Sepsis is a potentially life-threatening condition triggered by the body's response to an infection, causing injury to its own tissues and organs. It can progress rapidly and requires immediate medical attention. Early recognition and treatment are very important to reducing mortality.

Signs and Symptoms

Individuals with sepsis may present with a range of symptoms, including fever, low body temperature, rapid breathing, fast heart rate, confusion, and oedema. Early signs include a rapid heart rate, decreased urination, and high blood sugar. Established sepsis may lead to metabolic acidosis, low blood pressure, and disorders in blood clotting, which may cause organ failure. Fever is common, although it may be absent in the elderly or immunocompromised. A drop in blood pressure can cause lightheadedness, leading to septic shock. Oxidative stress, diastolic blood pressure reduction, and increased pulse pressure are other notable features.

Cause

Infections leading to sepsis are usually bacterial but can also be fungal, parasitic, or viral. Before antibiotics, gramme-positive bacteria were primary causes; after antibiotics, gramme-negative bacteria became predominant. Fungal sepsis, often from Candida species, accounts for 5% of severe cases, while parasitic causes include Plasmodium, Schistosoma, and Echinococcus. Common infection sites are the lungs, abdomen, and urinary tract, with the lungs being the most frequent.

Pathophysiology

Sepsis involves a combination of microbial factors and host immune responses. Bacterial virulence factors, such as glycocalyx and adhesins, play a role. The immune response to microbial antigens and damage-associated molecular patterns (DAMPs) triggers an uncontrolled immune response, leading to organ dysfunction. This involves increased lung vessel permeability, impaired liver oxygenation, acute kidney injury, heart failure, and altered mental status. Inflammatory cytokines can provoke blood clotting and endothelial damage, leading to multiple organ failure.

Diagnosis

Early diagnosis is essential. Within three hours of suspected sepsis, diagnostic studies should include white blood cell counts, serum lactate measurements, and obtaining cultures. Blood cultures, using bottles for aerobic and anaerobic organisms, help identify the causative organism. Other potential sources such as urine or cerebrospinal fluid should also be cultured. The sequential organ failure assessment (SOFA) score and quick SOFA (qSOFA) criteria, including respiratory rate, systolic blood pressure, and mental status, are used for diagnosis.

Management

Initial Management

Early recognition and intervention are very important. The "Sepsis Six" bundle, used in the UK, recommends administering antibiotics within an hour, obtaining blood cultures, measuring lactate and haemoglobin, monitoring urine output, providing high-flow oxygen, and administering intravenous fluids. Surgical drainage of infected fluid collections and organ support, such as hemodialysis and mechanical ventilation, are often necessary.

Antibiotics

Broad-spectrum antibiotics are recommended initially, and the choice should be re-evaluated daily. Treatment duration is typically 7–10 days, guided by culture results. For fungal infections, echinocandins or triazoles may be used.

Intravenous Fluids and Vasopressors

The Surviving Sepsis Campaign recommends an initial fluid resuscitation of 30 mL/kg in adults. If blood pressure remains low, vasopressors like norepinephrine are used.

Other Medications

The use of steroids in sepsis is controversial but may be considered if fluid resuscitation and vasopressors are inadequate. Mechanical ventilation, blood product transfusion, and nutritional support are very important components of ongoing management. Vitamin C administration may reduce sepsis mortality.

Prognosis

Sepsis has a high mortality rate, with approximately 24.4% fatality within 30 days and 34.7% in cases of septic shock. Elevated lactate levels indicate a worse prognosis. Cognitive decline may occur post-sepsis.

Epidemiology

Sepsis affects millions globally, with significant mortality rates, especially among the very young and elderly. It is the most common cause of death in hospitalised patients and the second leading cause of death in non-coronary ICUs.

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Self-assessment MCQs (single best answer)

Which of the following is NOT a common sign or symptom of sepsis?

What is the primary cause of sepsis?

Which score is used to diagnose sepsis by assessing respiratory rate, systolic blood pressure, and mental status?

Which of the following is NOT part of the "Sepsis Six" bundle?

What is the preferred initial fluid resuscitation volume for adults according to the Surviving Sepsis Campaign?

Which type of bacteria became a more predominant cause of sepsis after the introduction of antibiotics?

What is indicated by elevated lactate levels in a patient with sepsis?

Which of the following is a potential fungal cause of sepsis?

Which of the following is NOT typically considered in the initial management of sepsis?

Which cytokine action can lead to blood clotting and endothelial damage in sepsis?