Serum lactate dehydrogenase level in children with sickle cell disease at Kenyatta National Hospital

Abstract

Background Sickle Cell Disease (SCD) an inherited condition caused by a point mutation in the β- globin gene of hemoglobin. The laboratory diagnosis of SCD at Kenyatta national hospital (KNH) is through hemoglobin electrophoresis. At KNH, the follow up of patients with Sickle SCD aims at preventing malaria, pneumococcal infections and folate deficiency. Hydroxyurea is also prescribed to reduce the occurrence of certain SCD complications. Low socio-economic status coupled with lack of awareness about the disease in many of SCD patients is a hindrance to early diagnosis and contributes to poor adherence to treatment, shortened life expectancy, frequent sickle cell crises and early occurrence of complications. This has stimulated studies looking into the use of already existing, less expensive, effective laboratory tests for the detection of complications with possibilities of recommending their use in the routine follow up of SCD patients. This study was undertaken to look at serum lactate dehydrogenase (LDH) in SCD to find out if as a marker of hemolysis, its elevation would correlate with the clinical manifestations of the disease and the occurrence of complications. Objective To characterize the patterns of serum LDH levels among children with SCD aged 1-13 years attending Kenyatta National Hospital (KNH). Study design and setting Descriptive cross-sectional study conducted at the pediatric hematology clinic, pediatric filter clinic and the pediatric wards of KNH. The biochemical laboratory tests were done at the KNHclinical chemistry laboratory and the hematology tests were done at the University of Nairobi (UON) hematology laboratory. Methods: A total of 145 children with SCD aged 1 to 13 years were recruited into the study after an informed consent was signed by their parents or guardians. A questionnaire to collect data on age gender, presenting complaint, current medication used and recent medical history in the last one year was filled. Blood samples were collected for the total blood cell count, peripheral blood film, reticulocyte count and the total serum LDH level. Data handling The generated data from the questionnaire, the medical examination and the laboratory tests was entered into a computer data base, cleaned and analyzed through statistical software for analysis: SPSS (version 17.0). The results were expressed in graphs and tables and presented in mean/median and percentages. Results A total of 145 children were recruited into the study. Males were 57.2% while females were 42.8% and the median age was 5years (IQR: 3.0 - 9.0). The disease duration had a median of 36 months (IQR: 13 - 36 months). Hydroxyurea therapy was documented in 43.4% of the participants. The complications diagnosed at the time of presentation were thrombotic events accounting for 47.4% and these were represented by painful crises in 31.6%, neurological complications in 10.5% and skin ulcers in 5.3%; hemolytic complications were documented in 5.2% of participants while the presence of infections was documented in 47.4% patients. Serum LDH levels were measured in all the participants and a mean of 628 IU/L (reference range: 180- 360 IU/L) recorded. Majority of participants (93.8%) had serum LDH levels values above the reference range. Anemia was present in 97% participants and leukocytosis in 59% patients. Platelets counts within reference range were recorded in 80 % of the participants. No significant correlation was demonstrated between the serum LDH levels with the disease severity or the presence of complications. The study findings established a significant relationship between the elevation of serum LDH level and gender whereby male participants were predominant in the group with high serum LDH level. There was a significant correlation between the elevated serum LDH levels and presence of anemia. No statistically significant correlation was found between the serum LDH level, the white blood cells, platelet or the reticulocyte count. Conclusion: This study established a mean serum LDH level of 628.8 IU/L in children with SCD attending KNH. The most commonly diagnosed complications at presentation were thrombotic events and infections each documented in 47.4% patients. These complications showed no correlation with serum LDH level. Although a significant correlation between elevated serum LDH with gender and presence of anemia was seen, no significant correlation was found between the serum LDH levels, the WBC count, platelets count or the reticulocyte count. This study demonstrated that in children with SCD at KNH the serum LDH level is not a marker for severity of the clinical manifestation or predictor of complications of the disease. Study recommendations: From this study findings, serum LDH level may be used to predict for the presence of severe anemia in children with SCD at KNH. It however cannot be used as a marker of severity or to predict for disease severity and occurrence of complications.