What are blood clotting disorders?

Clotting is the result of a series of chemical changes in the blood. Blood clots help repair damaged blood vessels and stop bleeding. Special blood cells called platelets and proteins called clotting factors are involved in blood clotting.

Blood clots may also form when there is no injury or bleeding. They may block veins or arteries. This may interrupt blood flow to part of the body. The clots may prevent blood flow to organs, such as the brain, lungs, and heart.

Clotting disorders are a group of conditions in which people have excessive clotting. These disorders may be diagnosed in childhood, but are usually identified during the teen years and young adulthood. They are often genetic, meaning they are inherited and present at birth.

Some of the clotting disorders are:

  • Factor V Leiden. This inherited disorder increases the risk for deep vein thrombosis, a clot that develops deep in the body, usually in the leg. It also increases the risk of complications with pregnancy, such as miscarriage. It is the most common inherited clotting disorder. And it occurs most often in children whose families are from Europe. Although many people have this disorder, most never develop harmful blood clots.
  • Prothrombin thrombophilia. This clotting disorder is the second most common type. It also increases the risk for deep vein thrombosis and pregnancy complications, including slowed fetal development and miscarriage. It is also most likely to occur in those with families from Europe. And, only a small percentage of people with this disorder will ever develop harmful clots.
  • Protein C deficiency. The severity of this condition varies from mild to severe. Most people have no symptoms or have an increased risk for deep vein thrombosis. An infant with the severe form can develop tiny blood clots throughout his or her body. The clots may prevent blood flow and may cause tissue death.
  • Protein S deficiency. The severity of this condition also varies. As with protein C deficiency, most people have no symptoms or have increased risk for deep vein thrombosis. Those with the severe form can develop tiny blood clots that may lead to tissue death.
  • Antithrombin deficiency. This inherited disorder greatly increases the chance of developing blood clots. These clots may cause deep vein thrombosis or pulmonary embolism, a blood clot in the lungs.

What causes blood clotting disorders?

Clotting disorders are usually inherited conditions. Some illnesses may increase the risk of blood clot.

What are the risk factors for blood clotting disorders?

Many children with clotting disorders do not have blood clots. There are factors that increase the risk of getting clots as children get older. They include:

  • Use of birth control pills
  • Surgery
  • Injuries
  • Cancer
  • Being confined to bed for a long time
  • Pregnancy and postpartum, the time right after having a baby 

What are the symptoms of blood clotting disorders?

There are no symptoms of clotting disorders. However, if a deep vein thrombosis forms the symptoms are:

  • Swelling in an arm or leg
  • Soreness or pain in an arm or leg
  • Red, pale, or bluish skin color
  • Coolness or warmth over an area of an arm or leg

If a pulmonary embolism occurs the symptoms include:

  • Trouble breathing
  • Chest pain
  • A fast heartbeat
  • Coughing
  • A slight fever
  • Fainting

Pulmonary embolism is an emergency. If you think your child may have a clot in his or her lung, call 911 or go to an emergency room right away.

How are blood clotting disorders diagnosed?

In children, the diagnosis of a clotting disorder is based on medical history, current symptoms, and family history. Your child's provider will also examine your child. And blood tests include the following:

  • Complete blood count (CBC).  A complete blood count checks the red blood cells, white blood cells, and blood clotting cells (platelets). Sometimes, young red blood cells (reticulocytes) are also checked. It includes hemoglobin and hematocrit and more details about the red blood cells.
  • Clotting tests. This test determines the level of clotting factors in the child's blood and how long it takes to clot.
  • Genetic tests. To check gene defects known to cause clotting disorders.

How are blood clotting disorders treated?

Your child's provider will probably refer you to a hematologist. This is a specialist in blood disorders. Medications are the main treatment for clotting disorders. They include:

  • Anticoagulants, commonly called blood thinners, may be given intravenously (IV) or in your child's vein.
  • Aspirin may be used with anticoagulants.

Your child might need to take an anticoagulant for a long time. And, during high-risk periods (for example, if your child is confined to bed or has surgery), your child may need other medications to help manage or prevent clots.

What are the complications of blood clotting disorders?

Serious complications from clotting disorders are not common in children. But problems can occur. Complications include:

  • Problems with pregnancy and delivery, as girls get older
  • Pulmonary embolism
  • Stroke, if a clot blocks blood flow in the brain
  • Death 

How are blood clotting disorders managed?

Work with your child's health care provider to help prevent clots. As your child gets older, help him or her avoid things that further increase the risk of blood clots. These include:

  • Being overweight
  • Being inactive
  • Taking hormone contraceptives
  • Smoking

Since there are risks associated with pregnancy, women should get counseling before considering pregnancy.

For more information on blood clotting disorders or to schedule an appointment with a pediatric hematologist, call St. Louis Children's Hospital at 314.454.5437 or 800.678.5437 or email us.