What causes sickle cell anemia?
People with sickle cell anemia inherit the disease from their biological parents. In sickle cell anemia, the gene that helps make normal red blood cells mutates, or changes. People who inherit the mutated hemoglobin protein gene from both biological parents have sickle cell anemia. People who inherit the mutated gene from one biological parent have the sickle cell trait.
How does this mutation affect normal red blood cells?
Normal red blood cells contain hemoglobin. Hemoglobin is a protein and the main part of red blood cells. When the hemoglobin gene mutates, it creates sickled cells that can’t navigate the network of blood vessels that carry oxygen, nutrients and hormones throughout your body. Here’s why:
- Normal hemoglobin is soluble, meaning it dissolves in fluid. Abnormal hemoglobin isn’t as soluble and ends up forming solid clumps in your red blood cells.
- Red blood cells need to be flexible to squeeze and slide their way through narrow blood vessels. Red blood cells carrying abnormal solid hemoglobin can’t do that. Instead, blood cells with abnormal hemoglobin end up blocking blood vessels and blood flow.
- Normal red blood cells live about 120 days. Sickled cells self-destruct within 10 to 20 days. Normally, your bone marrow makes enough red blood cells to replace dying cells. When cells die earlier than usual, your bone marrow becomes like a factory struggling to match supply with demand. When the bone marrow factory can’t keep up, you don’t have enough red blood cells.
What are the signs and symptoms of medical conditions linked to sickle cell anemia?
Sickle cell anemia symptoms typically start when babies are 5 to 6 months old. As they grow older, most people with sickle cell anemia have increased risk for developing new medical conditions. Some of these conditions are life-threatening. But by learning about conditions and symptoms, people with sickle cell anemia can seek help at the first sign of trouble so healthcare providers can treat the condition.
Vaso-inclusive crisis (VOC)
Healthcare providers may call this condition acute pain crisis. VOC, or acute pain crises, is the most common reason why people with sickle cell anemia go to the emergency room or need to spend time in the hospital. Symptoms include:
- Sudden intense pain.
- Pain can be sharp or stabbing.
- VOC may affect any part of your body, but typically affects your abdomen, lower back, arms and legs.
Living with VOC is one of the more difficult aspects of having sickle cell anemia. Among other symptoms and complications, people who have sickle cell anemia may feel depressed or anxious because they’re dealing with certain stigmas associated with the condition.
Stigma and sickle cell anemia
Healthcare providers sometimes call VOC the invisible illness because people who are having a pain crisis many times don’t have symptoms other than sudden excruciating pain that’s only eased with opioid painkillers.
Studies show sickle cell anemia carries a stigma linked to people’s need for opioid painkillers to manage VOC. Other studies show people who are members of racial minorities receive less pain medication and have to wait longer for pain medication than people who are white. Combined, these stigmas are a one-two-punch, as sickle cell anemia commonly affects people who are Black or Hispanic.
Acute chest syndrome (ACS)
Acute chest syndrome is the most common complication of sickle cell anemia. It’s also the most common cause of death and the second most common cause of hospital admission. It happens when sickled cells clump and clog blood vessels in your lungs. Symptoms include:
- Sudden chest pain.
- Cough.
- Fever.
- Trouble breathing.
Anemia
People who have sickle cell anemia may have mild, moderate or severe forms of anemia. Symptoms include:
- Having skin color that’s more pale than usual.
- Fatigue. This is feeling too tired to manage daily activities.
- Trouble breathing.
In addition to these symptoms, babies with anemia may be unusually fussy or irritable. Children may not grow as fast as other children their age or may enter puberty later than children their age.
Stroke
Anyone who has sickle cell anemia is at risk for stroke, including babies. Approximately 11% of people with sickle cell anemia have strokes by age 20, and 24% have strokes by age 45. Here is information on stroke symptoms:
- Severe headache.
- Sudden weakness on one side of your or your child’s body.
- Change in alertness.
- Trouble speaking.
- Trouble seeing.
- Trouble walking.
Splenetic sequestration
This happens when sickled cells become stuck in your spleen, forcing your spleen to get larger. Splenic sequestration often causes acute anemia. Symptoms include:
- Pain in your upper left belly (abdomen).
- Sometimes, children’s enlarged spleens are visible or can be felt through their skin.
Bacterial infections
People with sickle cell anemia have an increased risk for infections caused by Streptococcus pneumoniae, Haemophilus influenzae and non-Typhi Salmonella species. Symptoms include:
- Fever.
- Coughing.
- Trouble breathing.
- Pain in bones.
- Headaches.
Priapism
About 35% of all people who are assigned male at birth (AMAB) who have sickle cell anemia develop priapism, or painful erections, that last four hours or more.
Leg ulcers
About 2% of people with sickle cell anemia develop leg ulcers, usually after age 10. Leg ulcers are more common in people AMAB and people age 65 and older. Symptoms are painful sores that don’t heal. People often develop these sores on their ankles.
Pulmonary hypertension (PH)
About 6% to 11% of people with sickle cell anemia develop pulmonary hypertension (PH). Symptoms include:
- Racing pulse.
- Fainting (passing out) or dizziness.
- Feeling short of breath during exercise or activity and difficulty breathing when at rest.
Chronic kidney disease
About 30% of people with sickle cell anemia have chronic kidney disease. Symptoms include:
- A need to pee (urinate) more often.
- Fatigue.
- Loss of appetite.
- Swollen hands, feet and ankles.
- Shortness of breath.
- Blood in pee (hematuria) or pee that looks foamy.
- Puffy eyes.
- Dry and itchy skin (pruritus).
- Trouble concentrating.
- Trouble sleeping.
- Numbness.
- Nausea or vomiting.
- Muscle cramps.
- High blood pressure (hypertension).
- Skin color that’s noticeably darker than usual.
Detached retina
Sickled cells can cause detached retinas by blocking blood vessels in your retinas. Common symptoms include:
- Seeing flashes of light.
- Seeing many floaters — flecks, threads, dark spots and squiggly lines that drift across your vision. (Seeing a few here and there is normal and not cause for alarm.)
- Darkening of your peripheral vision (side vision).
- Darkening or shadows covering part of your vision.
- Darkening or shadow covering part of your vision.
