title: Functional asplenia in hemoglobin SC disease.
abstract: The incidence of functional asplenia in sickle-hemoglobin C (SC) disease has not been defined, and the use of prophylactic penicillin to prevent life-threatening septicemia in this disorder is controversial. The percentage of red blood cells with pits (pit count) is a reliable assay of splenic function in other disorders but has not been validated in hemoglobin SC disease. To address these issues, we conducted a prospective, multicenter study of splenic function in persons with hemoglobin SC disease. Baseline clinical data were recorded, and red blood cell pit counts were performed on 201 subjects, aged 6 months to 90 years, with hemoglobin SC; 43 subjects underwent radionuclide liver-spleen scanning. Pit counts greater than 20% were associated with functional asplenia as assessed by liver-spleen scan, whereas pit counts less than 20% were found in subjects with preserved splenic function. Pit counts greater than 20% were present in 0 of 59 subjects (0%) less than 4 years of age, in 19 of 86 subjects (22%) 4 to 12 years of age, and in 25 of 56 subjects (45%) greater than 12 years of age. Other subjects with hemoglobin SC, who had previously undergone surgical splenectomy, had higher pit counts (59.7% +/- 9.5%) than splenectomized subjects without hemoglobinopathy (38.5% +/- 8.8%) or with sickle cell anemia (20.5% +/- 1.9%; P < .001). Two subjects with hemoglobin SC disease (not splenectomized), ages 14 and 15 years, with pit counts of 40.3% and 41.7% died from pneumococcal septicemia. These data indicate that functional asplenia occurs in many patients with hemoglobin SC disease, but its development is usually delayed until after 4 years of age. The pit count is a reliable measure of splenic function in hemoglobin SC disease, but values indicative of functional asplenia (> 20% in our laboratory) are higher than in other disorders. The routine administration of prophylactic penicillin to infants and young children with hemoglobin SC disease may not be necessary.
authors.affiliation: Colorado Sickle Cell Treatment and Research Center, University of Colorado School of Medicine, Denver, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Lane
authors.forename: J L
authors.initials: JL
authors.lastname: O'Connell
authors.forename: J L
authors.initials: JL
authors.lastname: Lear
authors.forename: Z R
authors.initials: ZR
authors.lastname: Rogers
authors.forename: G M
authors.initials: GM
authors.lastname: Woods
authors.forename: K L
authors.initials: KL
authors.lastname: Hassell
authors.forename: D L
authors.initials: DL
authors.lastname: Wethers
authors.forename: D W
authors.initials: DW
authors.lastname: Luckey
authors.forename: G R
authors.initials: GR
authors.lastname: Buchanan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000531:Altitude; D002648:Child; D002675:Child, Preschool; D003120:Colorado; D004198:Disease Susceptibility; D004906:Erythrocyte Count; D004913:Erythrocytes, Abnormal; D006450:Hemoglobin SC Disease / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000150:complications; D007223:Infant; D008875:Middle Aged; D012157:Mononuclear Phagocyte System / Q000503:physiopathology*; D011446:Prospective Studies; D011877:Radionuclide Imaging; D012306:Risk; D018805:Sepsis / Q000209:etiology*; D013154:Spleen / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014617:Vacuoles / Q000648:ultrastructure