Ischemia facts for kids

Quick facts for kids Ischemia
Synonyms	ischaemia, ischæmia
Vascular ischemia of the toes with characteristic cyanosis

Ischemia is when a part of your body, like a muscle or organ, doesn't get enough blood. This means it doesn't get enough oxygen, which is super important to keep it healthy and working.

It usually happens because of issues with your blood vessels. When blood flow is low, cells don't get enough oxygen. This can damage the tissues. Ischemia also means there's not enough oxygen in a body part because blood flow is blocked. This blockage can be from a blood vessel narrowing or a blood clot.

When a body part doesn't get enough blood, it also misses out on important nutrients. Plus, waste products can build up. Ischemia can be a partial blockage, meaning some blood gets through, or a total blockage. Doctors need to fix the cause of the low blood flow. Sometimes, they can also lower the body's need for oxygen. For example, if your heart isn't getting enough blood, doctors might give medicine. This medicine helps your heart work less hard.

What are the Signs of Ischemia?

The signs of ischemia can be different depending on where it happens. They also depend on how much blood flow is blocked. For example, if a limb (like an arm or leg) isn't getting enough blood, you might notice six main signs:

• Pain: The affected area hurts.
• Pallor: The skin looks pale.
• Pulseless: You can't feel a pulse in that area.
• Paresthesia: You might feel numbness or tingling.
• Paralysis: You can't move the limb.
• Poikilothermia: The limb feels cold.

If not treated quickly, ischemia can lead to tissue death. This can happen within just a few hours. If a limb becomes paralyzed, it means the nerves are severely damaged. Nerves are very sensitive to a lack of oxygen. Even after treatment, nerve damage might remain.

Heart Ischemia

Sometimes, the heart muscle doesn't get enough blood flow. This is called cardiac ischemia. It can cause chest pain, known as angina pectoris. This often happens because of atherosclerosis. This is when fatty plaques build up in the heart's arteries. In many countries, heart ischemia is a leading cause of death.

Bowel Ischemia

Both the large and small intestines can be affected by ischemia. If the large intestine (colon) doesn't get enough blood, it's called ischemic colitis. If the small bowel is affected, it's called mesenteric ischemia.

Brain Ischemia

Brain ischemia means the brain isn't getting enough blood. This can happen suddenly or over time. A sudden blockage, often from a blood clot, causes an ischemic stroke. If the brain has long-term low blood flow, it can lead to a type of dementia. A very short episode of brain ischemia is called a transient ischemic attack (TIA). People often call it a "mini-stroke." TIAs can be a warning sign for future, more serious strokes.

Limb Ischemia

When an arm or leg doesn't get enough blood, it can lead to acute limb ischemia. This means the blood flow stops suddenly. It can also lead to chronic limb threatening ischemia, which is a long-term problem.

Skin Ischemia

If the skin layers don't get enough blood, the skin might look blotchy or uneven. This is called mottling.

Kidney Ischemia

Kidney ischemia is when the kidney cells don't get enough blood. This can cause the kidneys to shrink. It can also lead to high blood pressure or kidney failure. This is a serious condition. If not treated, it can cause long-term kidney disease.

What Causes Ischemia?

Ischemia is a problem with blood vessels. It means the blood supply to a tissue, organ, or limb is interrupted. If not treated, this can cause the tissue to die.

Common causes include:

• Blood clots: A thromboembolism is a blood clot that forms and then travels.
• Foreign bodies: Sometimes, other things can block blood flow.
• Trauma: An injury to a limb can squeeze or tear a blood vessel. This can block blood flow.
• Aneurysm: This is a bulge in a blood vessel. It can be a common cause of sudden arterial ischemia.
• Heart problems: Conditions like a heart attack or irregular heartbeat can cause clots to form. These clots can then travel and block blood flow elsewhere.

Blood Vessel Blockages

Blood clots can break off and travel through your body. They can go anywhere in the circulatory system. If they block a vessel, the oxygen and blood supply beyond that point suddenly drops. How bad the symptoms are depends on the clot's size and location. It also depends on if the clot breaks into smaller pieces.

Other Causes

Sometimes, low blood flow can be caused by other things:

• Narrowed arteries: Atherosclerosis is when fatty plaques build up inside arteries. This narrows the space for blood to flow.
• Low blood sugar: Very low glucose levels.
• Fast heartbeat: An abnormally rapid heartbeat.
• Radiation: Radiation used to treat cancer can sometimes damage blood vessels over time.
• Low blood pressure: Very low blood pressure can mean not enough force to push blood around.
• Outside pressure: A tumor or other growth can press on a blood vessel.
• Sickle cell disease: This condition causes red blood cells to be abnormally shaped. They can block small blood vessels.
• G-forces: Strong forces, like in acrobatics, can push blood away from certain body parts.
• Extreme cold: Conditions like frostbite can restrict blood flow.
• Tourniquets: These medical devices are used to stop bleeding but also block blood flow.
• Bleeding: A serious bleed from a blood vessel can mean less blood reaches tissues.
• Anemia: When you don't have enough healthy red blood cells, your body might narrow blood vessels in your limbs. This sends more blood to vital organs, but leaves the limbs with less oxygen.
• Certain medications: Stopping blood-thinning medicines too soon can cause clots.
• Unusual body positions: If someone is unconscious, they might lie in a way that cuts off blood flow to a limb.

How Ischemia Harms Tissues

When tissues don't get enough blood, they get damaged. This happens because waste products build up. Cells also can't keep their outer layers healthy. Tiny powerhouses inside cells, called mitochondria, get damaged. Eventually, harmful chemicals leak out of the cells.

Sometimes, restoring blood flow to damaged tissues can cause even more harm. This is called reperfusion injury. When oxygen returns, it can create harmful molecules called free radicals. These molecules damage cells. Also, more calcium can rush into cells, which can be dangerous. Restoring blood flow also makes the body's inflammation response stronger. This can cause white blood cells to destroy cells that might have been saved.

Treating Ischemia

Getting treatment early is very important to save the affected body part. Doctors have several ways to treat ischemia:

• Anticoagulants: These are medicines that prevent blood clots from getting bigger.
• Thrombolysis: This involves injecting medicine directly into the blood clot. This medicine helps to dissolve the clot over a day or two.
• Embolectomy: This is a surgery to remove the blood clot.
• Surgical revascularization: This means surgery to restore blood flow. It might be needed if a blood vessel is damaged, for example, from an injury.
• Amputation: In very severe cases, if the limb cannot be saved, it might need to be removed.

If a patient is at risk for more blood clots, like from an irregular heartbeat, they might need to take blood-thinning medicine long-term.

Lowering the body temperature can help. It reduces how much oxygen the affected cells need. This helps reduce the immediate harm from lack of oxygen. It also helps reduce inflammation and reperfusion injury. For frostbite, doctors might wait to warm the tissues. This can help reduce damage when blood flow returns.

After an ischemic stroke, patients might be given medicines called statins. These medicines help lower the risk of future problems.

Organizations and Ischemia

The Infarct Combat Project (ICP) is a group started in 1998. It works to fight heart ischemia through education and research.

What Does "Ischemia" Mean?

The word ischemia comes from ancient Greek. It means "staunching blood" or "keeping back blood." It combines two Greek words: iskhο, meaning "keep back," and haima, meaning "blood."

See also

• Infarction

Images for kids

• 

  This graph shows how the heart's pumping ability changes after ischemia. Curve A shows a heart that is very weak after ischemia. Curve B shows that short periods of ischemia before a long one can help the heart recover better.