title: Avascular necrosis of the hip in children with sickle cell disease and high Hb F: magnetic resonance imaging findings and influence of alpha-thalassemia trait.
abstract: Avascular necrosis (AVN) of the hip is a common cause of morbidity in sickle cell disease (SCD). Its prevalence increases with age and predisposing factors include coexistent alpha-thalassemia trait, frequent vaso-occlusive crisis and a high hematocrit (Hct). SCD is relatively mild among Kuwaiti patients because of their elevated Hb F levels, but a subset exists with severe recurrent vaso-occlusive crises. We carried out a prospective magnetic resonance imaging (MRI) study of the hip in a group of patients being followed in the Pediatric Hematology clinics of Al-Mubarak and Al-Amiri Hospitals. The association of AVN with age, frequency of hospitalization, alpha-thal trait, steady-state Hb, Hct, Hb F, WBC and platelet counts was investigated. MRI was carried out with a 1.5-tesla GE unit with a super-conducting magnet. Thirty patients (19 males, 11 females) (23 SS and 7 SbetaThal) were studied. Their ages ranged from 6 to 17 years, with a mean of 9.8 +/- 3.5 years, and Hb F from 11 to 35% with a mean of 22.8 +/- 5.7%. Among the SS patients, 11 (47.8%) had coexistent alpha-thal trait (-3.7-kb deletion). A total of 8 (26.7%) patients (6 SS and 2 SbetaThal) had varying degrees of osteonecrosis of the hip. Four (36.4%) of the 11 SS patients with alpha-thal trait and 2 (16.7%) of those without alpha-thal trait had osteonecrosis. This difference is, however, not statistically significant (chi(2) = 0.3, p = 0.5). While there was also no significant difference in the mean age and hematological parameters (Hb, Hct, Hb F, WBC, platelets), the SS patients with osteonecrosis had a significantly higher number of hospitalizations for vaso-occlusive crisis in the preceding 3 years than those without osteonecrosis.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Kuwait University, Safat 13110, Kuwait. adekile@hsc.kuniv.edu.kw
authors.forename: A D
authors.initials: AD
authors.lastname: Adekile
authors.forename: R
authors.initials: R
authors.lastname: Gupta
authors.forename: F
authors.initials: F
authors.lastname: Yacoub
authors.forename: T
authors.initials: T
authors.lastname: Sinan
authors.forename: M
authors.initials: M
authors.lastname: Al-Bloushi
authors.forename: M Z
authors.initials: MZ
authors.lastname: Haider
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000235:genetics; D002648:Child; D005260:Female; D005271:Femur Head Necrosis / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology; D005319:Fetal Hemoglobin / Q000032:analysis*; D006579:Heterozygote; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017085:alpha-Thalassemia / Q000150:complications* / Q000235:genetics
chemical_list: D005319:Fetal Hemoglobin