Septic shock is a serious medical condition that occurs when sepsis, which is organ injury or damage in response to infection, leads to dangerously low blood pressure and abnormalities in cellular metabolism. The primary infection is most commonly caused by bacteria, management of hypovolemic shock pdf also may be by fungi, viruses or parasites.
Frequently, people with septic shock are cared for in intensive care units. It most commonly affects children, immunocompromised individuals, and the elderly, as their immune systems cannot deal with infection so effectively as those of healthy adults. Septic shock may be defined as sepsis-induced low blood pressure that persists despite treatment with intravenous fluids. Septic shock is a result of a systemic response to infection or multiple infectious causes. Sepsis may be present, but septic shock may occur without it.
Sepsis is a constellation of symptoms secondary to an infection that manifests as disruptions in heart rate, respiratory rate, temperature, and white blood cell count. The pathophysiology of septic shock is not entirely understood, but it is known that a key role in the development of severe sepsis is played by an immune and coagulation response to an infection. Both pro-inflammatory and anti-inflammatory responses play a role in septic shock. Most cases of septic shock are caused by gram-positive bacteria, followed by endotoxin-producing gram-negative bacteria, although fungal infections are an increasingly prevalent cause of septic shock. In gram-positive bacteria, these are exotoxins or enterotoxins, which may vary depending on the species of bacteria. These are divided into three types.
In gram-negative sepsis, free LPS attaches to a circulating LPS-binding protein, and the complex then binds to the CD14 receptor on monocytes, macrophages, and neutrophils. In response to inflammation, a compensatory reaction of production of anti-inflammatory substances such as IL-4, IL-10 antagonists, IL-1 receptor, and cortisol occurs. The hypoperfusion from the combined effects of widespread vasodilation, myocardial pump failure, and DIC causes multiorgan system failure that affects the liver, kidneys, and central nervous system, among other organ systems. Recently, severe damage to liver ultrastructure has been noticed from treatment with cell-free toxins of Salmonella. The ability of TLR4 to respond to a distinct LPS species are clinically important. Documented evidence of infection, may include positive blood culture, signs of pneumonia on chest x-ray, or other radiologic or laboratory evidence of infection.
This means that intravenous fluid administration alone is not enough to maintain a patient’s BP. Because lowered blood pressure in septic shock contributes to poor perfusion, fluid resuscitation is an initial treatment to increase blood volume. Treatment guidelines call for the administration of broad-spectrum antibiotics within the first hour following recognition of septic shock. Among the choices for vasopressors, norepinephrine is superior to dopamine in septic shock. While there is tentative evidence for β-Blocker therapy to help control heart rate, evidence is not significant enough for its routine use. There is tentative evidence that steroids may be useful in improving outcomes.
Tentative evidence exists that Polymyxin B-immobilized fiber column hemoperfusion may be beneficial in treatment of septic shock. Trials are ongoing and it is currently being used in Japan and Western Europe. 2011 Cochrane review was found not to decrease mortality and to increase bleeding, and thus, was not recommended for use. Sepsis has a worldwide incidence of more than 20 million cases a year, with mortality due to septic shock reaching up to 50 percent even in industrialized countries. Centers for Disease Control, septic shock is the thirteenth leading cause of death in the United States and the most frequent cause of deaths in intensive care units. The process of infection by bacteria or fungi may result in systemic signs and symptoms that are variously described.