SEPTIC SHOCK

Septic shock is a condition caused by an infection in the bloodstream (sepsis) in which blood pressure falls dangerously low and many organs malfunction because of inadequate blood flow.
There are several causes of shock, one of which is sepsis.
Septic shock occurs most often in newborns, people older than age 50, and people with a weakened immune system. People whose white blood cell counts are low (such as those who have AIDS or cancer or are receiving chemotherapy) and people who have a chronic disease (for example, diabetes or cirrhosis) are at greater risk of developing septic shock.
Septic shock is caused by cytokines (substances made by the immune system to fight an infection ) and by the toxins produced by some bacteria. These substances cause the blood vessels to widen (dilate), which results in a drop in blood pressure. Consequently, blood flow to vital organs—particularly the kidneys and brain—is reduced. This reduction in blood flow occurs despite the body's attempts to compensate by increasing both the heart rate and the volume of blood pumped. Eventually, the toxins and the increased work of pumping weaken the heart, resulting in a decreased output of blood and even poorer blood flow to vital organs. The walls of the blood vessels may leak, allowing fluid to escape from the bloodstream into tissues and causing swelling. Leakage and swelling can develop in the lungs, causing difficulty breathing (respiratory distress).
Symptoms and Diagnosis
Often, the first indications of septic shock are confusion and reduced mental alertness; these symptoms may be evident 24 or more hours before blood pressure drops. Other early symptoms may include a shaking chill; a rapid rise in temperature; warm, flushed skin; a rapid, pounding pulse; excessively rapid breathing; and blood pressure that rises and falls. Urinary output decreases. Tissues with poor blood flow release excess lactic acid into the bloodstream, causing the blood to become more acidic, which results in malfunction of many different organs. In later stages, the body temperature often falls below normal.
As septic shock worsens, several organs may fail. For example, the kidneys may fail, resulting in very low or no urine output and the accumulation of metabolic waste products (such as urea nitrogen) in the blood. The lungs may fail, resulting in breathing difficulties and a reduction in the level of oxygen in the blood. The heart may fail, resulting in fluid retention and swelling of tissues. Additionally, blood clots may form inside blood vessels.
To confirm the diagnosis of septic shock, a doctor may take and analyze blood samples. High or low levels of white blood cells, a decrease in the level of oxygen, a reduction in the number of platelets, excess lactic acid, and increased levels of metabolic waste products are all signs that a person may be in septic shock. A doctor may also use a fingertip sensor to monitor the level of oxygen in the blood. An electrocardiogram (ECG) may show irregularities in heart rhythm, indicating inadequate blood supply to the heart. Blood cultures are performed to identify the infecting organisms. Because there are other causes of shock besides sepsis, additional tests may be needed.
Treatment and Prognosis
As soon as symptoms of septic shock are apparent, the person must be admitted to an intensive care unit for treatment. Large amounts of fluid are given intravenously to increase the blood pressure. Drugs are given to increase blood flow to the brain, heart, and other organs. Extra oxygen is given. If the lungs fail, the person may need a mechanical ventilator to help breathing.
High doses of intravenous antibiotics are given as soon as blood samples have been taken for laboratory cultures. Until the laboratory identifies the infecting bacteria, two or more antibiotics are usually given together to increase the chances of killing the bacteria.
Any abscesses are drained, and any catheters that may have started the infection are removed. Surgery may be performed to remove any dead tissue, such as gangrenous tissue of the intestine. Despite all efforts, more than 25% of people with septic shock die.
(Merck Manual)