Although SCD can cause life-threatening complications, its effects can vary greatly among patients, with some experiencing relatively few and/or mild symptoms and complications, and others needing to be hospitalized frequently. Symptoms and/or complications of SCD usually begin by early childhood.
All of SCD's signs, symptoms, and complications stem primarily from two characteristics of red blood cells that contain predominantly hemoglobin S:
- They block the blood vessels during vaso-occlusive events.
- They have extremely short life spans.
Symptoms characteristic of sickle cell disease include:
Chronic anemia. The short life span of red blood cells in patients with SCD leads to chronic anemia (low red-cell count), which can cause extreme fatigue, shortness of breath, and delayed growth and development in children. In addition, the accelerated breakdown of hemoglobin can produce jaundice (yellowing of the eyes and skin) and an accumulation of bilirubin stones, a type of gallstone. Most SCD patients have had their gallbladders removed by early to middle adulthood.
Although most patients can tolerate moderate anemia for a long time, the condition can eventually contribute to life-threatening complications such as congestive heart failure.
Acute pain episodes. Many SCD patients suffer from intermittent, unpredictable, and recurring severely painful episodes that result from abnormal red blood cells getting stuck in small blood vessels. Pain can occur anywhere these cells block the oxygen flow to tissues, organs, and joints.
In adults, pain frequently occurs in the arms, legs, back, and chest and can last hours to days. Pediatric patients often experience these painful episodes in their hands and feet ("hand-foot syndrome"), which become swollen. Patients are often hospitalized and treated with painkillers and intravenous fluids for vaso-occlusive crises.
Stroke. Beginning in early childhood, people with SCD are at lifelong increased risk for stroke. While most strokes are characterized by a sudden loss of ability to move one or more limbs or to talk, with or without headache, some do not affect these functions. These "silent" strokes can still damage one's ability to think, manage emotions, and exercise good judgment about daily activities.
Most strokes suffered during childhood are ischemic strokes, caused by blockages of large blood vessels that lead to the brain. As people age, however, strokes are more frequently of the hemorrhagic variety, in which there is bleeding into the brain. Great strides have been made in preventing stroke and identifying patients at risk for stroke.
Acute chest syndrome. Approximately 75 percent of patients with SCD will suffer from at least one episode of acute chest syndrome, one of the most common causes of SCD-related mortality. Characterized by chest pain, fever, and shortness of breath, acute chest syndrome often looks like a severe case of pneumonia on chest X-rays, but an infectious cause is not usually found. Prompt treatment of acute chest syndrome usually leads to recovery.
Splenic sequestration and autoinfarction. Misshapen hemoglobin S cells can become trapped in the spleen, resulting in sudden episodes of a condition called splenic sequestration. Associated with life-threatening anemia, splenic sequestration can occur when a large number of a person's red blood cells suddenly become caught in the spleen and cause it to swell. Over time, vaso-occlusive crises in the spleen cause areas of the organ to die (autoinfarction), and it eventually shrinks to a nonfunctional remnant.
Recurring infections. Because SCD patients are prone to vaso-occlusion in the spleen—an organ that destroys bacteria and helps the body fight infections—they are especially susceptible to severe bacterial infections. It is imperative that patients who develop a fever be seen immediately by a doctor familiar with SCD.
Many SCD-related complications stem from the issues listed above. These include:
• Widespread organ damage. This can lead to organ failure, typically as a gradual process rather than an acute event.
• Chronic pain. Many patients older than their teens and 20s begin to experience daily pain from progressive bone and organ damage caused by vaso-occlusive episodes.
• Bacterial infections. Among those frequently seen are urinary tract and bladder infections, and osteomyelitis, an infection of the bone.
• Dehydration and kidney damage. SCD causes the kidneys to lose the ability to conserve water for the body, making it easy for patients to become dehydrated and, in some cases, resulting in kidney failure that necessitates dialysis or kidney transplantation.
• Delayed growth. Because SCD forces the body to produce a markedly increased number of red blood cells throughout life, growing children are faced with metabolic demands that often result in slowed growth and development. Other SCD-related factors may contribute to delayed development, as well.
• Pulmonary hypertension. High blood pressure in the blood vessels that supply the lungs affects about one third of adult SCD patients and is associated with shortened survival.
• Avascular necrosis. This condition, damage to bones caused by vaso-occlusion, typically affects the arms and legs—particularly the head of the major arm bone (humerus) and upper leg bone (femur), causing pain in the shoulders and hips. Many patients require joint replacement surgery.
• Painful and prolonged erections. At least 30 percent of boys and men sometimes experience this condition, known as priapism, which can lead to impotence.
• Psychosocial strain. SCD itself, as well as the pain and brain damage it can cause, can lead to problems in cognition and result in depression, anxiety, and feelings of isolation.
• Leg ulcers. Caused by insufficient blood supply to the skin, these often occur near the ankles.
• Retinal damage. Inadequate blood supply damages the retina, leading to visual impairment and sometimes blindness. SCD patients also may experience hemorrhages into the retina.
It is important that SCD patients understand their risks and seek specialized medical attention immediately if they experience signs and symptoms of any of these serious medical complications.
Last reviewed on 1/28/10
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