Multi Organ Dysfunction Syndrome

Multisystem Organ Dysfunction Syndrome : 

Multisystem Organ Dysfunction Syndrome By Chest Department Ain-Shams University Hospital

Multiple organ dysfunction syndrome (MODS) : 

Multiple organ dysfunction syndrome (MODS) is defined as a clinical syndrome in which the development of progressive and potentially reversible physiological dysfunction in 2 or more organs or organ systems induced by a variety of acute insults, including sepsis, is characteristic.

the American College of Chest Physicians/Society of Critical Care Medicine definitions of the various stages of sepsis: : 

the American College of Chest Physicians/Society of Critical Care Medicine definitions of the various stages of sepsis: Infection : the invasion of normally sterile host tissue by microorganisms . Bacteremia: is the presence of viable bacteria in the blood. Systemic inflammatory response syndrome (SIRS): may follow a variety of clinical insults, including infection, pancreatitis, ischemia, multiple trauma, tissue injury, hemorrhagic shock, or immune-mediated organ injury. Sepsis: is a systemic response to infection.

Septic shock is sepsis with hypotension (systolic BP <90 mm Hg or a reduction of 40 mm Hg from baseline) despite adequate fluid resuscitation. : 

Septic shock is sepsis with hypotension (systolic BP <90 mm Hg or a reduction of 40 mm Hg from baseline) despite adequate fluid resuscitation. Concomitant organ dysfunction or perfusion abnormalities (e.g., lactic acidosis) MODS is the presence of altered organ function in a patient who is acutely ill such that homeostasis cannot be maintained without intervention. Primary MODS is the direct result of a well-defined insult in which organ dysfunction occurs early and can be directly attributable to the insult itself. Secondary MODS The inflammatory response of the body to toxins and other components of microorganisms causes the clinical manifestations of sepsis.

The sepsis syndrome is recognized clinically by the presence of 2 or more of the following: : 

The sepsis syndrome is recognized clinically by the presence of 2 or more of the following: Temperature greater than 38°C or less than 36°C Heart rate greater than 90 beats per minute Respiratory rate greater than 20 breaths per minute or a PaCO2 in arterial gas less than 32 mm Hg WBC count greater than 12,000 cells/mL, less than 4000 cells/mL, or greater than 10% band forms

Pathogenesis: : 

Pathogenesis:

Specific organ involvement: : 

Specific organ involvement: Circulation Vasoactive mediators, Nitric oxide and impaired secretion of vasopressin cause vasodilatation and increase the micro vascular permeability at the site of infection . Central circulation: Changes in both systolic and diastolic BP→cardiac output increased to maintain the BP. Regional circulation: ↓organs blood flow→↓ oxygen delivery. Microcirculation: Increased endothelial permeability leads to widespread tissue edema of protein-rich fluid. Redistribution of intravascular fluid→ reduced arterial vascular tone, diminished venous return from venous dilation, and release of myocardial depressant substances causes hypotension.

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Pulmonary dysfunction Endothelial injury in the pulmonary vasculature → interstitial and alveolar edema. Neutrophil entrapment within the pulmonary microcirculation initiates and amplifies the injury to alveolar capillary membranes. (ARDS) is a manifestation. Gastrointestinal dysfunction and nutrition Overgrowth of bacteria in the upper GI tract may be aspirated into the lungs, producing nosocomial pneumonia. The normal barrier function of the gut may be affected, allowing translocation of bacteria and endotoxins into the systemic circulation and extending the septic response. Septic shock usually causes ileus, and the use of narcotics and sedatives delays institution of enteral feeding. The optimal level of nutritional intake is interfered with in the face of high protein and calorie requirements.

Gut origin model of MODS : 

Gut origin model of MODS

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Liver The reticuloendothelial system of the liver acts as a first line of defense in clearing bacteria and their products; liver dysfunction leads to a spillover of these products into systemic circulation. Renal dysfunction Due to systemic hypotension, direct renal vasoconstriction, release of cytokines ( TNF), and activation of neutrophils by endotoxins and other peptides, which contribute to renal injury. Central nervous system dysfunction --→ encephalopathy and peripheral neuropathy.

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Coagulopathy Sub clinical coagulopathy signified by → thrombin or activated partial thromboplastin time (aPTT) or ↓ platelet count , but disseminated intravascular coagulation (DIC) is rare. Deficiencies of coagulation system proteins, including protein C, antithrombin 3, and tissue factor inhibitors, cause coagulopathy .

Clinical: : 

Clinical: History: Symptoms of Sepsis Physical examination : The vital signs Investigate signs of systemic tissue perfusion Signs of infection: CNS ,Head and neck, Chest and pulmonary,Cardiac, Abdominal and GI, Pelvic and genitourinary, Bone,soft tissue and Skin infections .

Lab Studies: : 

Lab Studies: CBC count with differential →Maintain the hemoglobin at a level of 8 g/dL, Platelets and WBC count. Metabolic assessment: serum electrolytes, including magnesium, calcium, phosphate, and glucose. Renal and hepatic function assessment. ABG PT and aPTT Blood cultures Urinalysis and urine culture

Imaging Studies: : 

Imaging Studies: chest radiograph Supine and upright or lateral decubitus abdominal films Ultrasound →biliary tract sepsis. CT scan for excluding intraabdominal abscess or a retroperitoneal source of infection The detection of sepsis may require surgical exploration.

Procedures: : 

Procedures: lumbar puncture to diagnose meningitis or encephalitis. Cardiac monitoring, noninvasive BP monitoring, and pulse oximetry. Supplemental oxygen is provided during initial stabilization and resuscitation . A central venous line also can be used to monitor central venous pressure to assess intravascular volume status.

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urinary catheter to monitor urinary output and as a marker for adequate renal perfusion and cardiac output. Patients who have developed septic shock require right heart catheterization with a pulmonary artery (Swan-Ganz) catheter . Pulmonary dysfunction of sepsis (ARDS) also may occur. These patients need intubations and mechanical ventilation for optimum respiratory support.

Staging: Two well-defined forms of multiorgan dysfunction syndrome : : 

Staging: Two well-defined forms of multiorgan dysfunction syndrome : 1-the lungs are the predominant, and often the only, organ system affected until very late in the disease. Encephalopathy or mild coagulopathy may accompany pulmonary dysfunction. 2-These patients often have an inciting source of sepsis in organs other than the lungs, the most common being intraabdominal sepsis, extensive blood loss, pancreatitis, or vascular catastrophes. Acute lung injury or ARDS develops early, and dysfunction in other organ systems also develops.

Criteria for Organ Dysfunction : 

Criteria for Organ Dysfunction

Treatment: : 

Treatment: -Medical Care: consists of the following 3 major goals: (1) Resuscitate the patient from septic shock using supportive measures to correct hypoxia, hypotension, and impaired tissue oxygenation. (2) Identify the source of infection and treat with antimicrobial therapy, surgery, or both. (3) Maintain adequate organ system function guided by cardiovascular monitoring and interrupt the pathogenesis of multiorgan system dysfunction.

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- General supportive care Initial treatment includes support of respiratory and circulatory function, supplemental oxygen and mechanical ventilation. - Intravascular volume resuscitation sodium chloride 0.9% or Ringer lactate with repeat clinical assessments after each bolus. A total of 4-6 L may be required. Monitor patients for signs of volume overload. Colloid resuscitation (with albumin) has no proven benefit over isotonic crystalloid resuscitation .

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-Empirical antimicrobial therapy Must be broad spectrum and cover gram-positive, gram-negative, and anaerobic bacteria because all classes of these organisms produce identical clinical pictures (parenterally). -Vasopressor supportive therapy If the patient remains hypotensive despite volume infusion, initiate therapy with vasopressor agents (dopamine, norepinephrine, epinephrine, and phenylephrine).

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-Recombinant human-activated protein C -Corticosteroids -Surgical Care: when an infected focus persists. -Further Inpatient Care: -Temperature control -Metabolic support (hyperglycemia and electrolyte abnormalities,Correct anemia and coagulopathy

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Prevention. Prognosis: mortality ranging from 40-75% in patients with multiorgan failure of sepsis. The poor prognostic factors are advanced age, infection with a resistant organism, impaired host immune status, and poor prior functional status.

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Thank you