What is Shock?
Shock is a critical condition caused by a failure in blood circulation, which is dangerous to life. This failure leads to a lack of oxygen reaching cells and tissues, resulting in cell death and damage to major organs. In the early phases, the effects of shock can be reversed. However, if diagnosis or the start of treatment is delayed, it may bring irreversible changes including failure of multiple organs and even death.
What Causes Shock?
Shock occurs when your body isn’t getting enough oxygen. This can be because your body isn’t getting enough oxygen delivered to your cells, or because your body is using up oxygen too quickly. It’s a very serious condition that can cause your blood pressure to drop really low, and without quick treatment, shock could lead to death. Doctors describe four main types of shock: distributive, hypovolemic, cardiogenic, and obstructive. Each one is caused by different problems, but they all result in the same thing: your body not getting the oxygen it needs. Shock can be called “undifferentiated” if the doctors have figured out that you’re in shock, but haven’t yet found out why.
1. Distributive Shock:
This kind of shock happens when your blood vessels expand too much.
There are several types:
Septic Shock: This happens when your body’s response to an infection gets out of control. You can think of it as a “system crash”. It can lead to very low blood pressure and high levels of lactic acid in your blood (more than 2 mmol/L). You might need medicines to bring your blood pressure back up. The most frequent bacteria causing septic shock in the US are a type known as gram-positive bacteria, including pneumococcus and enterococcus.
Systemic Inflammatory Response Syndrome (SIRS): SIRS is when your body has an extreme reaction to infection or some non-infectious causes. Some of these non-infectious triggers can be pancreatitis, burns or different forms of embolism (blocks in the blood vessels caused by displaced fat, air or amniotic fluid).
Anaphylactic Shock: This is a severe allergic reaction that can make your blood pressure drop and cause breathing problems. This extreme reaction can happen within seconds to minutes after coming into contact with whatever you’re allergic to. Common triggers include certain drugs (like antibiotics or NSAIDs), foods, insect stings, and latex.
Neurogenic Shock: This can happen if you have a severe injury to your spinal cord or brain. It affects your nervous system, causing your blood vessels to expand and changing your heart rate.
Endocrine Shock: This happens when there’s a problem with your endocrine system, like adrenal failure (Addisonian crisis) or hypothyroidism (myxedema).
2. Hypovolemic Shock:
This kind of shock happens when you lose a lot of blood or other body fluids. At first, your body tries to keep blood flowing to your organs by narrowing your veins. But as you keep losing fluid, your heart can’t pump enough blood to your body, and your blood pressure drops. Hypovolemic shock could be caused by loss of blood (hemorrhagic) or loss of other body fluids (non-hemorrhagic).
Common reasons for blood loss could be gastrointestinal bleeding (bleeding in your digestive system), trauma, problems with your blood vessels, or bleeding caused by taking blood thinners.
Common reasons for losing other body fluids might be because of vomiting, diarrhea, taking diuretics (water pills), certain hormone disorders, burns, specific syndromes like Stevens-Johnson syndrome or Toxic epidermal necrolysis, heatstroke, fever, medical procedures or certain diseases like pancreatitis, cirrhosis or blockage of your intestines.
3. Cardiogenic Shock:
This kind of shock happens when your heart can’t pump enough blood to the rest of your body. It can caused by heart diseases (like myocardial infraction), heart rhythm problems ( arrhythmias), or mechanical problems inside your heart.
4. Obstructive Shock:
This kind of shock happens when something is blocking blood from flowing out of your heart. It might be because of a blocked blood vessel in your lung (like a clot or pulmonary embolism), severe high blood pressure in the arteries of your lungs, a buildup of air or fluid around your heart, or heart diseases causing your heart to stiffen.
Risk Factors and Frequency for Shock
Distributive shock is the most frequent type of shock, followed by hypovolemic and cardiogenic shock. Obstructive shock is relatively rare. Septic shock, which is a type of distributive shock, is the most common and has a death rate of 40 to 50%.
Signs and Symptoms of Shock
In order to understand a patient’s risk for shock, it’s important to examine their history, take a look at previous medical records, and consider their current health status. This includes studying their vital signs such as blood pressure. Symptoms and signs can differ based on the type of shock a patient might be experiencing. Generally, patients in shock may show signs such as:
- Low blood pressure (hypotension)
- Rapid heart rate (tachycardia)
- Rapid breathing (tachypnea)
- Being obtuse or having an abnormal mental status
- Cold, unusual skin texture, or an extreme drop in urine
- Acid build-up in the body (metabolic acidosis)
- Elevated lactate in the body (hyperlactatemia)
Different types of shock may show specific signs:
Patients with hypovolemic shock may additionally have orthostatic hypotension, pale skin, flat jugular veins, or show signs of chronic liver disease if a variceal bleed is the source.
Those with septic shock might show symptoms that point to the source of an infection, like certain skin conditions, or symptoms associated with blood infection.
Anaphylactic shock is usually associated with exposure to allergens a patient is sensitive to, and symptoms may include low blood pressure, skin flushing (redness), hives, rapid breathing, voice changes, face or mouth swelling, wheezing or a high-pitched noise when breathing in, and respiratory stridor.
Tension pneumothorax is a possible cause of unexplained shock, and symptoms can include rapid breathing, chest pain on one side, absent or faint breathing sounds, a shifting windpipe, bulging neck veins, and risk factors such as recent trauma, mechanical ventilation, or an underlying lung condition.
Pericardial tamponade can also cause undifferentiated shock, and symptoms can include shortness of breath, elevated jugular venous pressure, muffled heart sounds, low blood pressure, and pulses paradoxus (a drop in blood pressure during inhalation), especially in patients who have experienced trauma, previously had pericardial effusion, or underwent chest procedures.
Finally, in the case of cardiogenic shock, the patient may experience chest pain similar to that of a heart attack, narrow pulse pressure, elevated jugular veins, or lung crackles on examination, and abnormal heart rhythms on heart monitoring or electrocardiogram (EKG).
Testing for Shock
If you seem to be in a state of shock, doctors will immediately start trying to stabilize you before investigating what exactly is causing it. It’s crucial that doctors recognize and assess how severe the shock might be in order to know what treatments will be needed right away. To understand the situation, doctors will ask about your medical history and conduct a physical examination.
Along with real-time health monitoring, doctors will also take an electrocardiogram, or EKG, which is a test that can show if there is a problem with the way your heart is beating. An EKG can reveal signs of heart issues such as heart disease, irregular heartbeats, or evidence that might suggest you have had a heart attack or a blood clot in the lung.
The laboratory tests conducted on patients in shock usually include a complete blood count (CBC), tests to check how well your kidneys and liver are working, a test for lactate which can indicate if your tissues are receiving enough oxygen, a heart damage test, a blood clotting test, and a test to identify any possible infection. There will also likely be a blood test to determine your blood type in case you need a blood transfusion, particularly if you seem to be in shock due to severe blood loss. Initial scans recommended for patients in shock include chest x-rays that might reveal the source of an infection, such as pneumonia, or other clues that can aid in diagnosing the cause of the shock. CT scans can also be extremely helpful in pinpointing the cause of the shock. Ultrasound technology is another diagnostic tool regularly used by doctors.
Treatment Options for Shock
If you enter shock, the first steps that medical professionals will take is to stabilize your breathing. This might involve providing oxygen or using a machine to help you breathe. They will also establish a path to provide fluids and medications directly into your bloodstream. This can be done through a simple intravenous (IV) line in your arm, or in more severe cases, directly into your bone marrow or a large central vein.
The first priority is to ensure blood flow to your organs by filling up your blood vessels with fluids, and if necessary, they may use medications to help increase blood pressure and improve blood flow.
Depending on the cause of the shock, various treatments might be needed:
1) Septic shock (a severe infection): Doctors will start by giving large amounts of IV fluids quickly. Next, they will administer antibiotics to combat the infection. They might also use medications such as norepinephrine and vasopressin to help increase your blood pressure.
2) Anaphylactic shock (a severe allergic reaction): Treatment involves stopping exposure to the allergen, providing large amounts of IV fluids, and giving medications such as epinephrine, antihistamines, corticosteroids, and nebulized albuterol (a medicine you breathe in to help open up your airways).
3) Adrenal crisis (a severe deficiency in corticosteroids): This is typically treated with fluids and a corticosteroid medication called dexamethasone.
4) Hypovolemic shock (severe blood or fluid loss): The priority here is to quickly replace lost fluids through an IV. The use of red blood cell transfusions may be necessary in case of ongoing bleeding. Medical professionals will also act to stop the cause of your fluid loss.
5) Obstructive shock (blockage of blood flow to the heart): Treatment involves careful administration of IV fluids and additional medications like norepinephrine and vasopressin if needed. In some cases, like a major blood clot in the lungs (acute massive pulmonary embolism), they may need to use a clot-dissolving medication.
6) Cardiogenic shock (the heart can’t pump enough blood to provide for the body’s needs): Treatment may involve careful administration of IV fluids, medications to support heart function, or procedures to open blocked arteries or mechanically support the heart.
These treatments are designed to stabilize your condition and address the underlying cause of the shock.
What else can Shock be?
Identifying the cause of unexplained shock in a patient is extremely crucial. In such cases, the likely causes relate to the four main types of shock which were mentioned earlier. It’s also possible that the patient might be experiencing a mix of different shock syndromes. One other possible cause could be a condition known as “pharmacological shock” – this happens when certain medicines cause the blood vessels to widen or weaken the heart’s ability to pump blood. Such medicines could include benzodiazepines, beta-blockers, calcium channel blockers, opiates, anticholinergics, and sildenafil.
What to expect with Shock
Sepsis and septic shock are serious conditions that often lead to long-term health problems and sometimes death. Many survivors often need to be placed in facilities for long-term acute care or recover in centers for post-acute care.
Septic shock, a more severe form of sepsis, has a death rate between 40% and 50%. On the other hand, cardiogenic shock, which happens when the heart can’t pump enough blood to meet the body’s needs, has a death rate between 50% to 75%. Even though this is high, it’s actually an improvement from previous years.
There are less severe types of shock like hypovolemic and obstructive shocks, which occur respectively due to severe blood and fluid loss, and obstruction of blood flow in the heart. These types usually have much lower death rates and respond better to prompt treatment.
