by James Eckman, M.D. and Allan Platt, PA-C
Individuals with sickle cell trait are generally asymptomatic and have no abnormal physical findings. Their laboratory evaluation is normal with no anemia, no evidence of hemolysis, and no laboratory abnormalities other than hemoglobin AS on hemoglobin electrophoresis. Many individuals will have decreased ability to concentrate their urine. There may be an increased incidence of urinary tract infection during pregnancy. Painless hematurea does occur in 1 to 4 % of individuals with sickle cell trait . This complication is usually not a significant problem, however, a minority of individuals may have significant problems with recurrent hematurea requiring medical intervention, transfusion, and iron therapy. Complications such as splenic infarction, pain episodes, and sudden death may be induced by severe hypoxia, severe dehydration, and exertion at the limits of human endurance.
Present Illness. No symptoms
Past Medical History No medical problems
Family History. Document history of sickle hemoglobin, thalassemia, and other hemoglobin variants.
Review of Symptoms. Asymptomatic
- Physical examination is normal.
- Minimum Lab. CBC with reticulocyte count. Hemoglobin electrophoresis.
- Additional lab. None
- Sickle Cell Trait - The individual has no symptoms or physical findings that can be attributed to sickle cell trait. The diagnosis of sickle cell trait is established by an electrophoresis, isoelectric focusing or HPLC result that shows hemoglobin AS with about 55% hemoglobin A and 45% hemoglobin S. Hemoglobin, reticulocyte count and all laboratory tests are normal with sickle cell trait.
- Sickle Beta Plus Thalassemia - The individual with sickle beta plus thalassemia may have symptoms of sickle cell disease. Physical findings can include splenomegaly, retinopathy, avascular necrosis and other sickle cell complications. The hemoglobin may be normal or reduced, but the mean corpuscular volume is almost always reduced and the reticulocyte count is elevated. Elevated lactic dehydrogenase and indirect bilirubin levels are common. The diagnosis of sickle beta plus thalassemia is established by an electrophoresis, isoelectric focusing or HPLC result that shows hemoglobin SA with about 5 to 25% hemoglobin A and 65 to 90% hemoglobin S with elevated hemoglobin A2 and F.
- Sickle plus some other interacting hemoglobin structural variants. Individuals with hemoglobin SC disease are occasionally told that they have sickle trait by uninformed health professionals. Hemoglobin evaluation should be repeated if individuals with "trait" are symptomatic, anemic, or have evidence of hemolysis.
There are a number of hemoglobins that interact with sickle hemoglobin to cause symptomatic disease. These can be very difficult to differentiate from hemoglobin A on standard electrophoresis and isoelectric focusing. If a patient is symptomatic or has evidence of a hemolytic anemia and an HB AS pattern on electrophoresis or isoelectric focusing, further testing by reference laboratories may be indicated.
- Sickle Trait No therapy is required
- Sickle beta thalassemia and other Compound heterozygotes These are treated as sickle cell disease.
- Hematuria in Sickle Trait Microscopic or gross hematuria is an uncommon problem in individuals with sickle cell trait occurring in 1 to 4 % of individuals with Hb AS. When it occurs, it tends to be recurrent and can be severe and persistent. Iron deficiency, renal obstruction, infection, and other complications occur.
Treatment first requires a complete evaluation to exclude other causes of hematuria including cystitis, bladder, and renal tumors. Urine culture is always indicated. There is some evidence that medullary carcinoma of the kidney is more common in individuals with HB AS.
Initial treatment includes bed rest, vigorous oral hydration, administration of sodium bicarbonate to alkalinize the urine and diuretics and potassium if required. Individuals with persistent are admitted for strict bed rest and intravenous hydration with alkaline diuresis. Urologic intervention may be beneficial, however, nephrectomy to control bleeding is almost never indicated because of the high probability of recurrence in the contralateral kidney.
- Educate the carrier about the nature of sickle cell trait.
- Provide counseling of the risks of having children with sickle hemoglobin disorders.
- Inpatients with hematuria, monitor the patient fluid intake and output carefully, if fluid or sodium retention develops the doctor may order diuretics.
- Tell carriers to use caution during very strenuous exercise in hot weather or at high altitude. Inadequate fluid intake, and excessive perspiration can lead to dehydration with risk of splenic infarct or hematurea.
- Stress to the patient to continue taking the drug even when he feels better.
Individuals with sickle trait are at an increased risk of serious complications when exercising at the extremes of human endurance. Adequate hydration and avoidance of excessive fluid loss with minimize problems. With extreme hypoxia and dehydration, rarely complications like splenic infarction and pain episodes may occur. Hydration and grade exercise are important preventive measures. White individuals with sickle cell trait may be at higher risk for these complications. All individuals participating in sports, whether or not they have sickle cell trait, should have adequate hydration before during and after exertion in hot conditions.
Individuals with hematuria should actively hydrate themselves before during and after physical exertion. In individuals who have frequent, severe or persistent hematuria may need to avoid activities that regularly cause episodes. Hydration and bed rest may abort episodes if done imediately.
Parent and Patient Education
Patients and their families should be counseled about their risks of having a child with sickle cell disease based on their and their partners genotype. Both structural hemoglobin variants and beta thalassemia need to be excluded before providing such education.
Individuals with hematuria need to be educated about the benign nature of hematuria in sickle cell trait. Preventive measures and avoidance of precipitating activities need to be stressed in the rare individual with persistent or recurrent episodes. See our FAQ page on sickle cell trait by Clicking here
New Sports Guidelines for Sickle Cell Trait 8/17/2004 12:57:00 PM - New Youth Football Recommendations Emphasize Practice, Training Safety in the Heat; Expert Panel: Youth Football Coaches Key to Safety
-- Special precautions for sickle-trait football players should include no first-day preseason fitness runs, no timed distance runs, and no sustained sprints on the field, on hills, or on stairs. Assume that any cramping is due to red blood cell sickling until proven otherwise. Screening and precautions for sickle cell trait may readily reduce risk and save lives. See http://releases.usnewswire.com/GetRelease.asp?ReleaseID=34828
Sickle Cell Trait article by Dr. John Kark at http://sickle.bwh.harvard.edu/sickle_trait.html - An excellent and comprehensive review of potential problems facing those with sickle cell trait
Steinberg MH Sickle cell trait in Disorders of Hemoglobin: Genetics, Pathophysiology and Clinical Management. Steinberg MH, Forget BG, Higgs DR, Nagel RL. Cambridge University Press Cambridge UK 2001. Pp. 811-830.
Sears DA. Sickle Cell Trait in Sickle Cell Disease: Basic Principles and Clinical Practice Embury SH, Hebbel RP, Mohandas N, Steinberg MH eds. Raven Press NewYork pp. 381-394.
Sears DA. The morbidity of sickle cell trait: A review of the literature. Am J Med 64:1021-1036, 1978.
Kark JA, Posey DM, Schumacher HR et al. Sickle-cell trait as a risk factor for sudden death in physical training. New Engl J Med 317:781-787, 1987.
Kark JA, Ward FT. Exercise and hemoglobin S. Semin. Hematol 181-225, 1994.
McInnes BK III. The management of hamaturia associated with sickle hemoglobinopathies. J Urol 124:171-174, 1980.
Baldree LA, Ault BH, Chesney C, Stapleton FB. Intravenous desmopressin acetate in children with sickle cell trait and persistant macroscopic hematurea. Pediatrics 86:238-243, 1990.