Clinical and biological characterization of konzo forms in children in Kahemba/Democratic Republic of Congo

Abstract

Background Clinical and biological characteristics of three forms of konzo severity are still poorly documented. Objective Identify clinical as well biological and evolutive characteristics of three clinical patterns of konzo and associated disorders of other organs. Methods A literature review was undertaken in PubMed, Global Science.Org and Google scholar. In addition, data from 213 children including 124 cases and 89 controls from the NIH-DRC konzo project were used in the retrospective study. Sociodemographic factors, somatic, neurological and neuropsychological assessment data as well as biomarkers of malnutrition and cyanide intoxication were the variables of interest. Results The age of the children was higher in the severe form and lower in the mild form. Konzo disease severity was related to socio-economic distress, malnutrition and micronutrient deficiency (selenium, zinc and copper). Patellar and ankle exaggerated reflexes were more common in mild form thus ankle clonus, speech articulation disorders and Lhermitte sign were more frequent in moderate form. Socio-emotional, visual disorders and ankylosis had high frequency in severe form. Moderate form had shorter enzymatic detoxification rate thus higher urinary thiocyanate levels as well as some neurocognitive performances. Heart rate increased significantly with Konzo severity regardless of age. Frequently, severe form evolved towards mild form and vice versa. Conclusion Characteristics of three konzo clinical patterns within children suggest different models of adaptation to cyanide intoxication that require in-depth studies.