Sickle cell disease (SCD) is a blood disorder that is passed through the genes and results in abnormal hemoglobin. Hemoglobin is a part of the red blood cells that carry oxygen through the body. People with SCD have red blood cells that sickle, or change shape when exposed to low oxygen levels in the cell.
These sickled cells also become stiff and sticky compared to normal red blood cells. They can block blood flow, leading to tissue damage and pain. Over time, these blockages can lead to organ dysfunction and result in other serious medical complications.
Sickle Cell Disease Types
There are several different forms of sickle cell disease, and it is different for each person. Three types of SCD exist most often in the United States:
- Hemoglobin SS, also known as sickle cell anemia
- Hemoglobin SC disease
- Hemoglobin sickle beta-thalassemia
The most common and usually the most severe form is sickle cell anemia.
The SCD type affects the severity and frequency of complications. The type of SCD also impacts the timing of complications. Some people have symptoms at a very young age while others will not show symptoms until adulthood. In Wisconsin, screening and diagnosis shortly after birth became the standard in 1989. This is why people before 1989 have been diagnosed at different ages due to the timing of their symptoms prompting testing.
Sickle Cell Disease Symptoms, Crises and Complications
Symptoms and complications of SCD include:
- Anemia: Sickled blood cells are less able to carry oxygen, leading to anemia. Symptoms can include fatigue, weakness, dizziness, headache, shortness of breath and chest pain.
- Bone Pain: Decreased blood flow to the bones leads to periodic spikes in bone pain known as bone crises. SCD can also cause a-vascular necrosis, which is a breakdown of the bone and joint.
- End-Stage Organ Disease: Decreased blood flow can lead to organ failure, potentially affecting the kidneys, liver and heart.
- Eye Disease or Blindness: Sickled blood cells can damage the fragile blood vessels in the back of the eye, leading to retina damage called retinopathy. This can lead to blindness.
- Genital and Hormonal Issues: Complications include painful, unwanted erections of the penis, as well as delayed puberty.
- Heart Murmur or Enlargement: Restricted blood flow can lead to heart problems, such as murmur (an unusual sound that can mean a heart disorder) or an enlarged heart because your heart has to pump harder with SCD.
- Infections: The spleen fails in SCD patients at a young age, decreasing the body’s ability to fight infections.
- Liver and Gallbladder Issues: Gallstones, liver disease and jaundice, which is yellowing of the skin and eyes due to elevated bilirubin (liver values)
- Kidney Issues: Blood in the urine (papillary necrosis), frequent urination, kidney disease.
- Lower Extremity Ulcers: Older children and adults with SCD can develop sores on the lower leg.
- Lung Disease such as:
- Acute Chest Syndrome: Sickled cells in the lungs cause decreased blood flow, inflammation and acute lung injury. Patients may need to be on a ventilator (a machine to help them breathe).
- Pulmonary Hypertension: High blood pressure in the vessels that supply blood to the lungs.
- Pain: Can occur in many locations (such as the bones) and is the most common complication
- Stroke: Children with SCD between the ages of 6 and 10 are at high risk of stroke. Older patients have a lower overall risk of stroke, but they have a higher risk of dying from a stroke. Children with SCD tend to experience symptoms on an episodic basis. As patients enter adulthood, they tend to have chronic (occur all the time) symptoms and organ dysfunction (organs don't work as they should).