What Happens When Someone Loses Blood and What Causes It?

Causes of blood loss include wounds, underlying pathologies such as hemophilia and thrombocytopenia, menstruation and miscarriages. How blood loss affects the patient depends on the cause and how much blood they lose. However, in severe cases, they may experience unconsciousness and death, according to Healthline.

Some of the causes of blood loss include:

  • Wounds
  • Open wounds include surface grazes, puncture wounds, incisions and lacerations. Effects range from redness and swelling in the area to continuous blood loss resulting in dizziness and loss of consciousness.

  • Hemophilia
  • Hemophilia is a condition characterized by a lack of blood clotting factors. People with hemophilia are more likely to bleed severely because of injuries, including heavy internal bleeding.

  • Thrombocytopenia
  • Thrombocytopenia is characterized by having a low platelet count. As a result, people are prone to bruising, heavy nosebleeds and prolonged bleeding.

  • Menstruation
  • Most women who menstruate do not lose large amounts of blood. However, some suffer from menorrhagia, which includes extended periods of bleeding.

  • Miscarriage
  • Miscarriage is the loss of a pregnancy before 20 weeks. It is characterized by bleeding, which is heavier than menstruation.

When someone loses too much blood, they enter a state called hypovolemic shock. This is characterized by losing one-fifth or more of their normal blood volume, and as a result the heart is unable to pump hard enough to meet the body’s needs. People experiencing hypovolemic shock may become agitated, confused and weak. They also have low urine output, rapid breathing and cold or clammy skin. Eventually they experience unconsciousness, and if their blood supply is not replenished they will die.