Christopher P. Coppola, Alfred P. Kennedy, Jr. and Ronald J. Scorpio (eds.)Pediatric Surgery2014Diagnosis and Treatment10.1007/978-3-319-04340-1_55
© Springer International Publishing Switzerland 2014
Sickle Cell Anemia
(1)
Department of Pediatric Hematology/Oncology, Janet Weis Children’s Hospital, 100 N. Academy Av. MC 13-20, Danville, PA 17822, USA
Abstract
Sickle cell anemia is one of the first diseases understood at the molecular level. Valine substituted for glutamic acid in the beta globin subunit leads to decreased solubility in the de-oxygenated state. It may partially protect infants from cerebral falciparum malaria in the heterozygous state (sickle trait), and geographic distribution of the disease parallels the incidence of malaria.
Sickle cell anemia is one of the first diseases understood at the molecular level. Valine substituted for glutamic acid in the beta globin subunit leads to decreased solubility in the de-oxygenated state. It may partially protect infants from cerebral falciparum malaria in the heterozygous state (sickle trait), and geographic distribution of the disease parallels the incidence of malaria.
1.
Pathophysiology:
(a)
Hemoglobin S in the deoxygenated state polymerizes. This produces a change in the red blood cell from the biconcave disk to long rigid shapes: Polymerization and shape change is the disease and produces all the complications.
(b)
Acidosis, fever and dehydration increase the rapidity of polymerization/shape change and thus occlusion as well as the need to be treated aggressively in patients with sickle cell disease.
(c)
Sickle cells are damaged by repeated deoxygenation/shape changes and have a shortened life span. Sickle cell disease is one of the congenital hemolytic anemias with elevated reticulocyte count.
(d)
Disease severity is modulated by other hemoglobins:
(i)
Hemoglobin F (fetal) is elevated early in life which abolishes most complications.
(ii)
Hemoglobin C with hemoglobin S (HGB SC)- slightly milder form of disease
(iii)
Beta-thalassemia: presence of HGB A1 lessens severity of sickle cell disease complications. This effect is dependent on what percentage of hemoglobin is HGB A1.
(iv)
Sickle cell trait: HGB A1 > HGB S- patients are essentially asymptomatic.
2.
Diagnosis:
(a)
Hemoglobin electrophoresis is the gold standard; most new patients are diagnosed through newborn screening.
(i)
Newborn screening pattern depicts hemoglobin percentage in decreasing order.
1.
FA (normal): hemoglobin F percentage exceeds that of HGB A.
2.
FAS (sickle cell trait): Hemoglobin F is greater than HGB A, which is greater than HGB S.
3.
FSA (sickle cell/beta-thalassemia +): hemoglobin F is greater than HGB S, which is greater than HGB A.
4.
FSC (hemoglobin SC disease): hemoglobin F is greater than HGB S which is greater than HGB C.
5.
FS (hemoglobin SS or hemoglobin S/beta-thalassemia 0): hemoglobin F is greater than HGB S.
6.
These values will change as the infant ages; specifically the relative percentage of HGB F will decrease significantly to less than a few percent of the total hemoglobin.
3.
Clinical manifestations are highly variable:
(a)
Marked by the “sickle crisis”.
(b)
There are three major types:
(i)
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Vaso-occlusive crisis (VOC): acute often painful episodes caused by intravascular sickling with tissue infarction.
1.
Painful crisis: this is the major clinical manifestation of sickle cell disease. It affects bones, brain, liver, lungs, spleen, and penis. Pain is dull, throbbing, may or may not produce heat or redness. Patients often can differentiate sickle cell pain from pain secondary to other sources. Infants may present with hand-foot syndrome. Early onset (<age 1-year-old) correlates with increased later disease severity. Treatment includes analgesics, IV fluid, and transfusions.
2.
Acute chest syndrome (ACS): VOC affecting lungs. ACS is the leading cause of death over age 10-years-old. Hypoxia leads to further sickling which leads to worsening hypoxia. ACS treatment includes bronchodilators, incentive spirometry, pulmonary toilette, oxygen, transfusions, antibiotics including macrolides, and maintenance fluid.
3.
Abdominal pain: may mimic acute abdomen (patients may be able to differentiate acute abdomen from usual sickle cell abdominal pain). Common etiologies include gallstones and mesenteric sickling. Treatment: Fluids, analgesia, and antibiotics to “cool down” the gallbladder prior to cholecystectomy.
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