### Date : 2024-11-06 22:56 ### Topic : Septic Shock #medicine ---- **Septic Shock** is a severe and potentially fatal condition that occurs when **sepsis** (a body-wide infection) leads to a **dangerously low blood pressure** that cannot be maintained even with fluid resuscitation. This critical drop in blood pressure reduces blood flow to organs, causing tissue hypoxia and, if untreated, can rapidly lead to multiple organ failure and death. ### Pathophysiology of Septic Shock Septic shock develops as the body’s inflammatory response to an infection spirals out of control, leading to widespread damage and dysfunction: 1. **Systemic Inflammatory Response**: - In response to infection, the immune system releases pro-inflammatory cytokines like **TNF-alpha**, **IL-1**, and **IL-6**. This widespread inflammation can damage tissues and disrupt normal blood vessel function. 2. **Vasodilation and Capillary Leakage**: - Inflammatory mediators cause **vasodilation** (widening of blood vessels) and increased permeability of capillaries, allowing fluids to leak out of the bloodstream into tissues. This leads to **edema** and reduces blood volume within vessels, dropping blood pressure. 3. **Coagulopathy**: - The inflammatory response activates the **coagulation cascade**, causing microvascular clotting, which can obstruct blood flow to organs (a condition known as **disseminated intravascular coagulation, or DIC**). 4. **Reduced Oxygen Delivery**: - Low blood pressure, combined with reduced blood volume and microvascular thrombosis, leads to inadequate oxygen delivery to organs. Cells become hypoxic, impairing cellular metabolism and causing lactic acidosis. 5. **Organ Dysfunction**: - As oxygen delivery declines, organs fail to function properly, leading to shock and, eventually, **[[Multiple organ dysfunction syndrome (MODS)]]** if untreated. ### Causes and Risk Factors Septic shock is triggered by infections, with the most common sources being: - **Respiratory tract infections**: Pneumonia is a frequent cause. - **Urinary tract infections**: Particularly in elderly patients or those with indwelling catheters. - **Abdominal infections**: Infections like peritonitis, which spread throughout the abdominal cavity. - **Skin and soft tissue infections**: Including cellulitis, infected wounds, or surgical site infections. **Risk Factors** for developing septic shock include age (very young or elderly), weakened immune systems, chronic diseases (e.g., diabetes, kidney disease), recent surgery, and the use of invasive devices like central lines or urinary catheters. ### Clinical Presentation of Septic Shock Septic shock often presents with: 1. **Low Blood Pressure (Hypotension)**: - Persistent hypotension that does not respond to fluid resuscitation, requiring vasopressors to maintain adequate perfusion pressure (mean arterial pressure ≥ 65 mmHg). 2. **Signs of Organ Dysfunction**: - **Altered mental status**: Confusion, disorientation, or lethargy, often due to reduced brain perfusion. - **Respiratory distress**: Rapid, shallow breathing as the body tries to compensate for metabolic acidosis. - **Oliguria**: Reduced urine output, a sign of kidney dysfunction. - **Cyanosis or mottling**: Discoloration of the skin due to poor perfusion. 3. **Elevated Lactate Levels**: - Elevated **serum lactate (>2 mmol/L)** indicates tissue hypoxia and impaired cellular metabolism. Lactic acidosis is a key marker of septic shock severity. ### Diagnosis of Septic Shock The diagnosis of septic shock involves recognizing the signs of sepsis and hypotension, supported by laboratory and imaging tests: 1. **Clinical Criteria (Sepsis-3 Definition)**: - Septic shock is defined as sepsis with **persistent hypotension requiring vasopressors** to maintain a mean arterial pressure (MAP) of at least 65 mmHg and **serum lactate >2 mmol/L** after adequate fluid resuscitation. 2. **Laboratory Tests**: - **Blood cultures**: To identify the causative organism. - **Lactate levels**: An indicator of tissue hypoperfusion. - **Complete blood count (CBC)**: White blood cell (WBC) count may be elevated or decreased. - **Organ function tests**: Assessing kidney function (creatinine), liver enzymes, and coagulation markers. - **Inflammatory markers**: C-reactive protein (CRP) and procalcitonin levels may be elevated. 3. **Imaging**: - Imaging, such as chest X-ray, ultrasound, or CT scan, can help identify the source of infection. ### Treatment of Septic Shock Early and aggressive treatment is critical to improving outcomes in septic shock. The primary goals of treatment are to **control infection**, **restore hemodynamic stability**, and **support organ function**. 1. **Antibiotic Therapy**: - Broad-spectrum antibiotics are administered as soon as septic shock is suspected, typically within the first hour. Antibiotic choice may be refined once the causative organism is identified. 2. **Source Control**: - Draining abscesses, removing infected devices, or performing surgery may be necessary to eliminate the source of infection. 3. **Fluid Resuscitation**: - Intravenous fluids, usually crystalloids, are given to restore blood volume and support blood pressure. - Fluids are carefully monitored, as excessive fluid administration can worsen edema and tissue oxygenation. 4. **Vasopressors**: - If hypotension persists despite fluid resuscitation, vasopressors (such as **norepinephrine**) are administered to maintain adequate MAP (≥65 mmHg). - In some cases, **vasopressin** or **epinephrine** may be added if blood pressure remains low. 5. **Corticosteroids**: - Low-dose corticosteroids (e.g., hydrocortisone) may be used if blood pressure is unresponsive to fluids and vasopressors. - Steroids help reduce inflammation and support hemodynamic stability. 6. **Organ Support and Monitoring**: - **Respiratory Support**: Oxygen therapy or mechanical ventilation may be necessary if respiratory failure occurs. - **Renal Support**: Dialysis may be required in cases of acute kidney injury. - **Monitoring**: Continuous monitoring of vital signs, lactate levels, urine output, and organ function is essential to assess treatment response and adjust therapies. ### Complications of Septic Shock Septic shock can lead to multiple severe complications, including: - **Multiple Organ Dysfunction Syndrome (MODS)**: As blood flow and oxygenation decrease, organs fail progressively, leading to high mortality. - **Disseminated Intravascular Coagulation (DIC)**: A coagulation disorder causing microvascular clotting and hemorrhage. - **Long-Term Sequelae**: Survivors may suffer from post-sepsis syndrome, which includes long-term physical, cognitive, and emotional difficulties. ### Prognosis Septic shock has a high mortality rate, with estimates ranging from 30% to 50%, depending on patient age, health status, and the speed of diagnosis and treatment. Early recognition and aggressive management are critical to improving survival outcomes. ### Summary - **Septic Shock**: A life-threatening condition where sepsis causes a dangerously low blood pressure and leads to organ dysfunction. - **Symptoms**: Persistent hypotension, altered mental status, respiratory distress, low urine output, and elevated lactate levels. - **Diagnosis**: Based on persistent hypotension and elevated lactate after fluid resuscitation, with additional lab and imaging support. - **Treatment**: Prompt antibiotics, source control, fluid resuscitation, vasopressors, corticosteroids, and organ support. Septic shock is a critical emergency requiring immediate, coordinated medical intervention to reduce mortality and improve outcomes. --- **Case Presentation:** **Patient:** 72-year-old female **Chief Complaint:** Fever, confusion, and shortness of breath --- **History of Present Illness:** - Onset: Symptoms began 2 days ago with fever and chills. - Progression: Increasing confusion and lethargy over the last 24 hours. - Associated Symptoms: Productive cough with yellow-green sputum, shortness of breath, and decreased urine output. - Past Medical History: Type 2 diabetes mellitus, hypertension, and chronic kidney disease (Stage 3). --- **Physical Examination:** - **Vital Signs:** - BP: 80/50 mmHg (hypotensive) - HR: 120 bpm (tachycardic) - Respiratory Rate: 24 breaths/min - Temperature: 39°C - Oxygen saturation: 88% on room air - **General Appearance:** - The patient appears acutely ill, diaphoretic, and disoriented. - **Lungs:** Crackles bilaterally, decreased air entry at the bases. - **Cardiovascular:** Tachycardic with a regular rhythm, weak peripheral pulses. - **Abdomen:** Mildly tender with no guarding or rebound. --- **Laboratory Results:** - CBC: Elevated WBC (17,000 cells/µL), increased neutrophils - Lactate: 4.5 mmol/L (elevated) - Serum creatinine: 2.0 mg/dL (elevated from baseline of 1.3 mg/dL) - Blood culture: Pending - Sputum culture: Pending **Imaging:** - **Chest X-ray:** Bilateral infiltrates, suggestive of pneumonia. --- **Diagnosis:** - **Septic Shock** secondary to **community-acquired pneumonia** --- **Management Plan:** 1. **Initial Resuscitation:** - **Fluids:** Rapid infusion of IV crystalloid fluids (30 mL/kg) to improve perfusion. - **Vasopressors:** Start norepinephrine if MAP (mean arterial pressure) remains <65 mmHg after initial fluids. 2. **Antibiotic Therapy:** - Broad-spectrum antibiotics (e.g., piperacillin-tazobactam and vancomycin) initiated promptly to cover likely pathogens pending culture results. 3. **Supportive Measures:** - Oxygen therapy to maintain SpO₂ > 92%. - Monitor urine output closely to assess kidney function. 4. **Monitoring:** - Serial lactate measurements to gauge response to therapy. - Repeat blood cultures if there’s no clinical improvement within 48–72 hours. --- **Teaching Points:** 1. **Sepsis and Septic Shock:** Defined by hypotension needing vasopressors and elevated lactate despite adequate fluid resuscitation. 2. **Management:** Early recognition and aggressive fluid resuscitation are critical; antibiotics should be started within 1 hour. 3. **Complications:** Multiorgan failure (e.g., kidney injury, respiratory distress) if not managed promptly. --- ### Reference: - ### Connected Documents: -