Article History
Received: 21 February 2019
Accepted: 19 August 2019
First Online: 17 September 2019
Compliance with ethical standards
:
: All authors declare that they have no conflicts of interest.
: This study was approved by the Research Ethics Committee, Faculty of Medicine, Cairo University, approval number R-7-2016. The current study followed the ethical standards of Helsinki declaration.
: The purpose of the study was explained to the guardians of children and they all signed an informed consent.