Also called:
- bacteremic shock
- septicemic shock
Septic shock is a serious condition caused by an infection in the bloodstream (sepsis) that results in low blood pressure and low blood flow to vital organs.
During an infection, some types of bacteria make and release substances called toxins (endotoxins) that trigger an immune response. When endotoxins are released into the bloodstream they cause:
- large blood vessels to become wider (dilate)
- small blood vessels (capillaries) to leak, which allows fluid to seep from the bloodstream into tissues
As a result, blood pressure drops and the flow of blood to vital organs (e.g. kidneys, brain) is reduced. The body reacts by increasing the heart rate and the amount of blood being pumped. This weakens the heart, there is decreased output of blood and even less blood flow to important organs. Organs cannot function properly if they don't get enough blood.
Causes
- bacteria (most common)
- bacteria may be introduced into the bloodstream by catheters, intravenous equipment, surgical or medical procedures
- fungi and viruses
- weakened immune system, which can be caused by:
- the cancer itself
- cancer treatments such as chemotherapy or radiation therapy
- immunosuppressive therapy with drugs such as corticosteroids
- low white blood cell count (neutropenia)
- prolonged antibiotic therapy
- recent pre-existing infection such as urinary or gastrointestinal tract infections, or skin ulcers
- chronic diseases (e.g. diabetes)
Symptoms
The symptoms of septic shock depend on how severe it is. The first sign of septic shock is often confusion and reduced mental alertness. Other early signs may include:
- fever
- shaking chills
- low blood pressure
- rapid heart rate – because the heart works harder to compensate for a decrease in blood pressure and blood flow
- difficulty breathing or shortness of breath – because of fluid accumulation in the lungs or reduced oxygen level in the blood
- low or no urine output – because the kidneys may start to fail
- restlessness
- warm limbs (extremities)
Later signs of septic shock can include:
- cool, pale and clammy extremities
- below-normal temperature
- blood clotting problems causing an increased risk of bleeding or blood clots to form
Diagnosis
Diagnostic tests are done to find out the source of infection and evaluate the severity of septic shock:
- blood tests
- complete blood count (CBC) which may indicate an infection
- blood cultures to identify the bacteria or organisms causing the infection
- blood gases to measure the level of oxygen (oxygen saturation) in arterial blood
- applying a special sensor clip to a fingertip to estimate oxygen saturation in the blood (pulse oximeter)
- electrocardiogram (ECG) to measure heart beat and heart rhythm
- an inadequate blood supply to the heart can cause an irregular heart beat
- urinalysis or urine for culture and sensitivity (C & S) to check for urinary tract infection
- chest x-ray to check for possible pneumonia
- cultures of mouth sores, skin sores, stool samples or intravenous sites to check for sources of infection
Treatment
People with septic shock are usually treated in an intensive care unit. Treatment includes:
- frequent monitoring of blood pressure, heart rate and breathing
- intravenous fluids to increase blood pressure
- medications to increase blood pressure and blood flow to the brain, heart, and other vital organs
- intravenous antibiotics to kill the bacteria or other organisms causing infection
- the choice of antibiotics depends on the type of bacteria present
- 2 or more antibiotics may be used until the infecting organism is identified
- oxygen therapy
- mechanical ventilation for severe breathing problems
- removal of any catheters that could have started the infection
- surgery to drain an abscess or remove dead tissue that could have started the infection
Infections can rapidly progress and be life-threatening in some cancer patients if they are not successfully treated.