Shock occurs when there is severely diminished blood flow (hypoperfusion) to the body’s tissues and organs. It is caused by major medical events.
Shock can begin suddenly, such as immediately after a serious injury involving rapid blood loss or with an acute cardiac episode. It can also develop gradually, such as with a chronic illness that prevents blood from traveling through the body as it should.
Situations that cause shock include:
- Dehydration: Lack of body fluid
- Hemorrhage: Bleeding within the body or blood loss from the body
- Anaphylaxis: A major, possibly fatal, allergic reaction
- Neurogenic problems: Difficulty controlling blood pressure and pulse due to brain and/or spine damage
- Heart attack: A sudden disruption in the heart function and heartbeat
- Pericardial tamponade: Physical pressure around the heart muscle
- Pneumothorax: A collapsed lung
During major physical stress, such as that caused by sepsis, neurological damage, and anaphylaxis, the body cannot maintain normal control over blood pressure and pulse. This is described as hemodynamic instability, and it interferes with blood flow to the tissues.
Being severely dehydrated or having an infection or heart failure can make you more prone to shock.3 That said, shock can affect anyone at any age.