Shock is a life-threatening medical condition that occurs when the body’s organs and tissues do not receive enough blood flow. This prevents them from getting enough oxygen and nutrients to function properly. There are several different types of shock, each with their own causes, symptoms, and treatments.
What is Shock?
Shock is characterized by low blood pressure and the failure of the circulatory system to provide adequate perfusion (blood flow) to vital organs. Without enough oxygen and nutrients, the cells of the body’s tissues and organs begin to die. This can lead to serious organ damage or even death if left untreated.
Some of the key characteristics and symptoms of shock include:
- Low blood pressure
- Rapid, weak pulse
- Rapid, shallow breathing
- Pale, clammy, cool skin
- Confusion or loss of consciousness
- Nausea and thirst
Shock requires immediate emergency medical treatment to restore blood flow and oxygen/nutrients to the body’s organs. It can arise from a number of different causes, which determines the type of shock and how it is treated.
Types of Shock
There are several different classifications of shock that can occur:
Hypovolemic Shock
Hypovolemic shock is caused by a significant loss of blood or fluids, resulting in insufficient volume circulating to provide adequate perfusion. Causes include:
- Major external or internal bleeding from trauma
- Severe burns involving large surface area
- Severe dehydration from vomiting, diarrhea, sweating, etc.
- Excessive urination from diabetes insipidus
Treatment involves stopping any bleeding, replacing lost fluids through IV infusion, and potentially blood transfusion if there is extensive blood loss.
Cardiogenic Shock
Cardiogenic shock occurs when the heart is unable to pump strongly enough to meet the body’s circulatory needs. Causes include:
- Heart attack
- Congestive heart failure
- Cardiomyopathy
- Arrhythmias
- Heart valve disorders
Treatment involves medications to improve heart function, insertion of a balloon pump to mechanically assist circulation, or placing the patient on ECMO (extracorporeal membrane oxygenation).
Septic Shock
Septic shock is triggered by an overwhelming systemic infection leading to dangerously low blood pressure. Causes include:
- Bacterial infection (e.g. appendicitis, pneumonia)
- Viral infection (e.g. influenza, coronavirus)
- Fungal infection
- Parasitic infection (e.g. malaria)
Treatment involves high-dose IV antibiotics, draining any abscesses, and supporting vital organ function with fluids/medications until the infection is under control.
Anaphylactic Shock
Anaphylactic shock is caused by a severe systemic allergic reaction to a food, medication, or insect sting toxin. The immune system releases flood of chemicals that result in lowered blood pressure and breathing difficulties. Epinephrine injection is urgently needed to counteract the immune system reaction and support circulation/breathing.
Neurogenic Shock
Neurogenic shock is caused by damage to the nervous system that disrupts signals to blood vessels, preventing them from constricting appropriately and leading to pooling of blood in peripheral tissue. Causes include:
- Spinal cord injury
- Brain trauma
- Drug overdose
Treatment involves IV fluids to stabilize blood pressure and support to ensure adequate oxygenation/perfusion to organs.
Recognizing Shock
The key to survival in shock is rapid recognition and prompt emergency treatment. Symptoms can appear at different rates depending on the cause of shock:
- Early signs: Restlessness, thirst, pale/cool damp skin, nausea, dizziness, rapid breathing
- Progressing signs: Weak/rapid pulse, low blood pressure, confusion, weakness, loss of consciousness, collapse
Any symptoms of shock require activation of the emergency response system to get the patient transported immediately to the nearest hospital for assessment and treatment.
Most Common Causes
The most common causes of shock requiring emergency medical treatment include:
Hypovolemic Shock
Around 5% of trauma patients and up to 30% of burn patients experience hypovolemic shock from blood/fluid loss. Car accidents, falls, gunshot wounds, and other traumatic injuries that cause significant external or internal bleeding are frequent triggers. Severe vomiting, diarrhea and heavy sweating leading to dehydration can also result in hypovolemic shock.
Septic Shock
Septic shock has a mortality rate of around 40-50% and requires rapid treatment with IV fluids and antibiotics. While sepsis can occur from many different infections, common sources include pneumonia, kidney infection (pyelonephritis), bowel perforation, pancreatitis, and sepsis from a central IV catheter.
Cardiogenic Shock
Around 7-10% of patients who have heart attacks affecting a large area of heart muscle will develop cardiogenic shock. Heart failure patients are also susceptible during acute exacerbations of their condition. According to the AHA, cardiogenic shock complicates about 6% of heart failure cases.
Anaphylactic Shock
Anaphylactic shock from an acute allergic reaction is less common, but when it occurs is it critical to treat rapidly with epinephrine. Foods (especially nuts), insect sting venom, and medications are the most frequent triggers. An estimated 1 in 200 inpatient hospitalizations involve anaphylaxis, with around 1,000 deaths per year in the U.S.
Mortality Rate from Shock
The mortality rate for shock depends significantly on the underlying cause and how rapidly it is treated. Some key statistics on death rates:
- Septic shock – 40-50% mortality
- Cardiogenic shock – 40-50% mortality
- Hypovolemic shock – Around 20% mortality if blood loss is severe
- Anaphylactic shock – less than 3% mortality if treated promptly with epinephrine
Overall, shock carries a high risk of death if not treated aggressively and rapidly. Heart disease and severe infection are the most common precipitating conditions.
Shock Prevention
While some causes of shock like anaphylaxis or hypovolemia from trauma are difficult to predict and prevent, there are measures that can reduce the risk of developing certain kinds of shock:
- Careful monitoring of heart health and control of conditions like congestive heart failure to lower cardiogenic shock risk
- Staying up to date on vaccinations, such as flu and pneumonia shots, to prevent infection
- Good wound care and infection control practices during procedures and hospitalization
- Medication adherence and glucose control for diabetes to prevent complications
- Avoiding known triggers for allergy or anaphylaxis when possible
Public awareness campaigns on recognizing shock symptoms early and activating EMS can also improve outcomes and lower mortality when shock does occur.
Shock Diagnosis
Doctors will rapidly assess a patient with suspected shock to evaluate symptoms and try to identify the type of shock involved. Tests may include:
- Blood pressure and pulse monitoring
- Checking temperature and skin condition
- Listening to heart and lung sounds
- Blood tests to assess cell counts, electrolytes, kidney function
- Urine output measurement
- ECG to evaluate heart rhythm and function
- Cultures to test for infection
- CT scans to identify internal bleeding or infection source
Rapid access to the patient’s medical history is also useful for identifying conditions like heart failure or severe allergies that could be contributing to shock.
Emergency Shock Treatment
Hospital emergency departments have specialized equipment and medications ready to initiate urgent resuscitation and treatment for shock patients. Steps include:
- Starting IV access and giving IV fluids to help stabilize blood pressure
- Giving supplemental oxygen
- Using a ventilator for breathing support if oxygen levels are critically low
- Administering ECG and cardiac monitors to evaluate heart rhythm and function
- Giving medications based on the suspected cause of shock such as epinephrine for anaphylaxis or antibiotics for septic shock
- Urgent surgery or procedures like imaging scans to stop internal bleeding or drain infection
- Monitoring kidney function and conducting dialysis if needed
- Transfusing blood products if required to address blood loss
Admission to intensive care for close monitoring and significant medication/device support is often required in severe shock cases.
Shock Follow Up Care
Patients who survive shock will require close follow up care to monitor for potential complications during their recovery:
- Ongoing lab testing to ensure organ function is stabilizing
- Medications tailored to the cause of shock, such as antibiotics after septic shock
- Heart monitoring and treatment of residual heart damage from cardiogenic shock
- Physical therapy to rebuild strength after prolonged hospitalization
- Nutritional support if needed to address deficits caused by shock
- Counseling for PTSD or depression which can occur after a traumatic shock episode
Some patients may require temporary placement in a skilled nursing facility before they can be discharged home, especially if they have weakness requiring rehabilitation. Close follow up is key during the weeks and months after significant shock.
Key Takeaways
- Shock is a life-threatening medical emergency requiring urgent treatment when blood flow to organs is compromised
- Symptoms like low blood pressure, confusion, and rapid heart rate signal shock
- Hypovolemic, cardiogenic, and septic shock are the most frequent types
- Prompt diagnosis and management of shock is crucial to improving the chances of survival and limiting organ damage
- Preventive healthcare like vaccines and heart disease control can reduce shock risk in some cases
- Patients recovering from shock require extensive follow up care to monitor for complications
The Bottom Line
Shock is a complex, dangerous condition that can result from various underlying medical causes. Hypovolemic, septic, and cardiogenic shock account for most cases. Rapid recognition of shock and initiation of emergency treatment is absolutely vital to save lives and give patients the best chance of recovery with limited organ dysfunction. Public awareness combined with prepared emergency services skilled in shock resuscitation are key factors in improving survival of shock. Patients who are stabilized following shock require extensive aftercare to manage residual issues and optimize restoration of their health.