Complications of Sickle Cell Disease

Reviewed by: HU Medical Review Board | Last reviewed: January 2021

People with sickle cell disease (SCD) can experience many complications of the disease. Symptoms and complications are different for each person and can range from mild to severe. Complications tend to worsen over time.

Causes of complications

People with SCD have an abnormal form of hemoglobin inside red blood cells. This abnormal hemoglobin builds up and causes red blood cells to become rigid and sickle-shaped.1

Sickle cells get stuck because they are not flexible enough to bend through small blood vessels. They also tend to stick more to each other and the walls of blood vessels. This can block blood flow and prevent oxygen from reaching many different organs. Lack of oxygen because of blocked blood flow can lead to:2

Sickle cells also live about 85 percent shorter than normal red blood cells (20 days compared to 120 on average). The body cannot make enough red blood cells to make up for this. This lack of red blood cells causes anemia. People with SCD can experience many complications of anemia, which may be severe.3

When too many sickle cells burst, they release contents that can cause inflammation and narrowing of blood vessels.2

Common complications

Acute pain crisis

Acute pain crises (also known as sickle cell or vaso-occlusive crises) are the most common cause of hospital visits for people with SCD. They happen when sickle cells block blood flow and oxygen delivery, causing pain in the muscle and bones. Acute pain crises usually affect the:2,4

  • Abdomen
  • Arms
  • Back
  • Chest
  • Legs

Acute chest syndrome

Acute chest syndrome is the second-most common cause of hospital visits for people with SCD. It happens when a lack of oxygen damages the lungs. It often follows an acute pain crisis. Acute chest syndrome can be life-threatening and should be treated in a hospital.4,5


People with SCD can experience clinical and silent strokes. This means they may or may not show outward signs of a stroke. It is usually caused by blocked blood flow to the brain and can occur alone or with acute chest syndrome. Children have the highest risk of acute stroke, and 25 percent of adults with SCD have a stroke by age 45.4,6

Delayed growth and puberty

Anemia causes children with SCD to grow slower than their peers. They will reach sexual maturity, but usually a couple years later than normal.4,7

Eye problems

Sickle cells can block blood vessels in the retina. This is the area of the eye that sends visual signals to the brain. When the retina is damaged, vision loss and blindness can occur.8


Red blood cells release hemoglobin when they burst. In the blood, hemoglobin breaks down to a pigment called bilirubin. When too many cells burst, bilirubin builds up and collects in the gallbladder, forming clumps. This is called gallstones, or cholelithiasis.2


People with SCD have a higher risk of infection because the spleen is often damaged and cannot protect against infections. Infections were a leading cause infant mortality until the use of preventive antibiotics and additional vaccinations.2,9

Splenic sequestration

The spleen filters out blood and destroys old blood cells. Since sickle red blood cells die early and quickly, they can get stuck in the spleen. This makes the spleen grow too large and leads to splenic sequestration crisis and severe anemia. This is a leading cause of infant mortality.2,4

Joint pain

Sickle cells can decrease oxygen delivery to the hip joints. This can lead to a condition called avascular necrosis, and it can severely damage joints. It can also happen to the joints of the shoulders, knees, and ankles. This can cause chronic pain and problems with movement.4,10

Kidney problems

One-third of people with SCD develop chronic kidney disease, and some require dialysis or a kidney transplant. This usually happens because SCD prevents the kidneys from making urine properly.4,11

Leg ulcers

Sores can develop on the lower part of the leg. Some heal quickly, but others can last for long periods of time. They are most common in people 10 to 50 years old. Infection, inflammation, and blocked blood flow in the leg can lead to leg ulcers.4,8

Liver failure

Severe liver damage can occur when blood vessels in the liver are blocked. For some adults with SCD, chronic problems can lead to liver failure.4


Priapism is a prolonged, painful erection. It can happen when blood flow out of the penis is blocked. Over time, this can cause permanent damage and infertility.4

Depression and anxiety

Depression and anxiety are very common in people with SCD. They are linked to greater sensitivity to pain, greater healthcare use, and lower sleep quality.2,12

Sleep disorders

Sleep-disordered breathing is common in children and adults with SCD. In children, this can lead to behavioral problems and learning difficulties. In adults, it can increase pain severity and risk of developing chronic pain.13,14

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