Sickle cell anemia

Alternative names:

anemia - sickle cell; Hemoglobin SS disease (Hb SS); Sickle cell disease

Treatment:

No cure is available for the disease. The objective of therapy is the comprehensive management and control of symptoms relating to crises.During a crisis, bed rest is recommended to reduce energy expenditure and oxygen needs. Maintaining adequate oxygen levels prevents the acidosis which causes sickling.

Supplementation with Folic acid, an essential element in producing cells, is required because of the rapid red blood cell turnover. Acute painful episodes are treated with analgesics and adequate liquid intake. Sometimes the spleen become damaged from these aberrant red blood cells and must be removed (splenectomy). Blood transfusions may be given for aplastic or hemolytic crises, but should not be given routinely. Patients who have had a splenectomy are given a pneumococcal vaccine to prevent overwhelming infection. Since this vaccine is not very effective in children, children with splenectomies receive penicillin to prevent infection until they are old enough for the vaccine to be effective. Oral or intravenous fluids are given to dilute the blood and replace lost electrolyte. Blood transfusions are given for symptomatic or severe anemia, low oxygen (hypoxia) accompanying acute chest syndrome, and to prevent recurrent strokes. It is possible for patients to become addicted to the narcotics used to treat painful episodes. However, patients with sickle cell are not more likely to become addicted than other patients taking analgesics for common pain. Nevertheless, this remains a real concern.

There are specific treatments available for the complications of sickle cell anemia. These include antibiotics for infection; partial exchange transfusion (and, rarely, intubation or even extracorporeal membrane oxygenation -ECMO-) for acute chest syndrome; potentially partial exchange transfusions or surgery for neurological events such as strokes; dialysis or kidney transplant for kidney disease; irrigation or surgery for priapism; surgery for eye problems; hip replacement for avascular necrosis of the hip (death of the joint); gallbladder removal if there is significant gallstone disease; wound care, zinc oxide or surgery for leg ulcers; drug rehabilitation and counseling for the psychosocial complications.

Hydroxyurea (Hydrea) was found to help some patients to produce a more normal blood protein reducing the frequency of painful crises and of acute chest syndrome, and reducing the need for blood transfusions. However, it may cause leukemia if used for extended periods of time. Therefore, is recommended only for those patients at great risk for complications of the disease.

Newer drugs are being developed to manage sickle cell anemia. Drugs such as clotrimazole may help prevent dehydration, which can cause sickling. One drug now being tested improves the shape of sickled cells so they can move through blood vessels more easily. Vasodilators (drugs which dilate blood vessels) such as nitric oxide (NO) may also keep blood vessels from becoming blocked, improving acute chest syndrome. Antioxidants may also help, but their role is not well understood.

About 1% of the hemoglobin produced in the human body is fetal hemoglobin (Hb F). Even people with sickle cell anemia produce normal Hb F. Drugs such as butyric acid, which cause the body to produce more Hb F than normal, can therefore help treat sickle cell anemia. Bone marrow transplants are currently the only potential cure for sickle cell anemia. However, it is difficult to find the right bone marrow donor, and the drugs needed to make the transplant possible are highly toxic. Also, bone marrow transplants are much more expensive than other treatments. Gene therapy may be the ideal treatment, but it has not yet been tested in humans.

Parents should encourage their children to lead normal lives, but in order to decrease the occurrence of sickle cell crises, the following precautions should be considered:
A. To prevent tissue deoxygenation, avoid the following:
1. strenuous physical activity, especially if the spleen is enlarged.
2. emotional stress
3. environments of low oxygen content (high-altitudes, non-pressurized airplane flights)
4. known sources of infection
B. To promote hydration:
1. recognize signs of dehydration
2. avoid excess exposure to the sun
3. provide access to fluids, both at home and away
C. To avoid sources of infection:
1. Keep child properly immunized as recommended by the health care provider.
2. Consider having the child wear a Medic Alert Bracelet.
3. Share above information with teachers and other caretakers as appropriate.
4. Be aware of the effects that chronic, life-threatening illnesses can have on siblings, marital relationships, parents, and the child.

Support groups:

Sickle cell anemia, like other chronic, life-threatening diseases, can cause great stress to the patient and family members. Joining a support group, where members share common experiences and problems, can relieve this stress. See sickle cell anemia - support group.

Expectations (prognosis):

In the past, death from organ failure occurred between the ages of 20 and 40. More recently, because of better understanding and management of the disease, patients live into their forties and fifties. Causes of death include organ failure and infection. Some people with the disease experience minor, brief, and infrequent episodes. Others experience severe, prolonged and frequent episodes resulting in many complications.

Complications:

• recurrent aplastic and hemolytic crises
• multisystem disease
• narcotic abuse
• splenic sequestration syndrome
• Acute chest syndrome (this occurs in 40% of patients. It is less common in adults than in children, but adults experience more severe episodes)
• Erectile dysfunction (as a result of priapism) · Blindness/visual impairment
• Stroke (10% of patients in childhood)
• Joint destruction (10-50% of patients)
• Gallstone disease
• Infection, including pneumonia, cholecystitis (gallbladder), osteomylitis (bone), and urinary tract infection
• Parvovirus B19 infection resulting in aplastic crisis
• papillary necrosis (tissue death) of the kidney
• removal of the spleen (splenectomy) if the spleen has atrophied.
• Miscarriage (6% of pregnant women)
• Leg ulcers (20% of patients)
• Death

Calling your health care provider:

Call your health care provider if acute painful crises occur or at the first sign of any infection.

References:

Miller ST, Sleeper LA, Pegelow CH, Enos LE, Wang WC, Weiner SJ, Wethers DL, Smith J, Kinney TR: Prediction of adverse outcomes in children with sickle cell disease. New England Journal of Medicine 342 (2): 83-9, 2000 Jan 13.

Steinberg MH: Management of sickle cell disease. New England Journal of Medicine 340(13): 1021-30; 1999 Apr 1.

Updated Date: 05/08/00

Updated by: Bradley G. Somer, MD, Division of Hematology-Oncology, Hospital University of Pennsylvania, Verimed Health Network