Septic Shock

Septic shock is a potentially life-threatening condition.

• Septic shock describes a catastrophic situation where infection overwhelms the body's immune system and potentially causes organ failure and death.
• By definition, blood pressure is low, organs like the heart, lung, kidney, and liver fail to work properly, and medications are required to support and maintain blood pressure in a normal range
• Infections that cause sepsis and shock usually arise from the lung (pneumonia), abdomen, or urinary tract.
• Patients in septic shock need treatment in the ICU (intensive care unit).
• Early administration of intravenous antibiotics is the mainstay of treatment.
• Mortality rates are as high as 50% for people in septic shock.

The definition of septic shock is ever changing as the medical community learns more about how the body fails in the face of overwhelming infection. The Society of Critical Care Medicine and the European Society of Intensive Care Medicine agreed upon the most recent definitions in 2017.

Sepsis is a life-threatening bacterial infection that causes a generalized inflammatory response in the body that affects the immune system and causes it to not respond properly to the infection. This may result in the failure of the body's organs.

The formal definition of sepsis: "life-threatening organ dysfunction caused by a dysregulated host response to infection." The SOFA score (sequential sepsis related organ failure assessment -- a scoring system to assess and track a patients severity of sepsis) needs to be 2 or more.

Septic shock is a worsening of sepsis and hypotension (low blood pressure) requiring medications (vasopressors) to increase blood pressure into the normal range and elevated lactate levels in the blood (lactate is a measure of waste products on the blood) define it. Vasopressors are intravenous medications that are continuously infused that increase blood pressure by narrowing arteries and increasing the heart's pumping capabilities.

The formal definition of septic shock: "circulatory, cellular, and metabolic abnormalities are associated with a greater risk of mortality than with sepsis alone. These patients can be clinically identified by a vasopressor requirement to maintain a MAP ≥ 65mmHg and serum lactate >2mmol/L in the absence of hypovolemia."

SOFA criteria assign points for blood pressure, platelet count, lung function (oxygen levels in the blood), brain function (Glasgow Coma Scale), and liver and kidney function.

The quick SOFA score (qSOFA) measures blood pressure, respiratory rate, and Glasgow Coma Scale).

Doctors do not understand the exact mechanism as to why sepsis and septic shock occur.

Bacterial infections that invade the body and overwhelm the immune system cause sepsis and septic shock.

Most commonly, the initial infection arises in the lung (pneumonia), kidneys (urinary tract infection), or abdomen (GI=gastrointestinal) tract.

Less commonly, infections may begin in the skin (cellulitis or abscess), central nervous system (meningitis), and bone (osteomyelitis).

Risk factors for developing septic shock include the following:

• Patients at extremes of age, including the elderly and the very young
• Those with underlying medical illnesses like diabetes, liver disease, kidney disease, or cancer
• Patients with immune compromise: This may include those on chemotherapy or other medications that affect the body's ability to fight infection.
• IV drug users
• Delay in making the diagnosis of an infection
• Delay in starting antibiotic treatment increases the risk of developing sepsis

Patients in septic shock are critically ill. In addition to the signs and symptoms of the underlying infection, they may also have

• low blood pressure,
• rapid heart rate,
•  increased breathing rate,
• fever,
• shakes,
• chills (Some very ill patients may be cold and no longer able to mount a fever response to infection.),
• confusion,
• lethargy,
• anxiety,
• nausea, and
• vomiting.

An initial diagnosis begins with the care provider taking a history and performing a physical exam to try to find the source of the infection. Because these patients are critically ill and unstable, the history and physical often occur at the same time as medical professionals take blood tests and X-rays, and start the patient on intravenous fluids.

Initial blood tests may include a complete blood count (CBC), chemistries to look at electrolyte levels, kidney and liver function, coagulation tests, and blood lactate levels.

Searching for the source of infection may include getting a urine sample and chest X-ray. Other X-rays and CT scans will depend upon where the search for the source of infection takes the provider and patient.

Medical professionals perform blood cultures and urine cultures to try and identify the type of bacteria causing the infection.

Your doctor may perform a lumbar puncture to obtain a sample of cerebral spinal fluid if there is concern for meningitis or encephalitis. Medical professionals will then culture the cerebral spinal fluid.

The initial treatment for septic shock incorporates the ABCs of resuscitation (airway, breathing, circulation). Patients in septic shock need to be admitted to an intensive care unit for treatment. This may include intubating the patient and using a ventilator to help with breathing.

Intravenous fluids support blood pressure. By definition, for it to be septic shock, a vasopressor medication (for example, dopamine, dobutamine, epinephrine, norepinephrine) also needs to be required to help elevated blood pressure.

Early intravenous antibiotics are important to fight the underlying infection and empiric broad spectrum antibiotic therapy is recommended. Even if the source of infection is known, the type of bacteria, and how susceptible it might be to a specific antibiotic is not. For that reason, your doctor will start you on multiple antibiotics, and as test results return, only those antibiotics that work against a specific infection will be continued.

The cause of the original infection, as well as what organs are failing, will determine other treatment options.

By definition, septic shock requires that various organs in the body fail to work. These include the heart, lungs, liver, and kidneys among others. If the infection cannot be controlled and treated, at the same as vital signs are being restored (circulation and breathing), the patient may die.

Septic shock is a catastrophic worsening of sepsis. The prognosis is dire, even with the best of intensive care, with mortality rates approaching 50%. With early diagnosis and aggressive treatment, mortality rates may be closer to 10%.