Dear Editor,
We read with interest the article titled “Analysis of regular screening of children in schools for the blind - Its importance” by Kavitha and Heralgi.[1] The authors have highlighted the importance of regular screening of children in blind schools to identify children with blindness due to treatable conditions. We appreciate the authors’ efforts and research. We would like to highlight few points regarding pyridoxine-dependent epilepsy (PDE), which is known to cause strabismus and incomplete/delayed myelination, thereby resulting in avoidable blindness.
Prematurity and its neurological sequelae, including seizures, should not stand against the likelihood of PDE as a possible diagnosis.[2] Chinta et al.[3] evaluated the etiology and clinical features of optic atrophy in 324 children (583 eyes) <16 years of age. Hypoxic-ischemic encephalopathy (HIE) was the most common cause of childhood optic atrophy (133 children) in this study. Twenty patients in the HIE group were preterm. Two patients had intracranial hemorrhage. Forty children had squint and defective vision. Our assumption is PDE should be considered as a differential diagnosis in this subset of children. Squint and incomplete/delayed myelination is a feature of PDE.[4] Our assumption is that PDE caused optic atrophy due to impaired myelination, resulting in defective vision and strabismus. PDE may be misdiagnosed as HIE.[5] To conclude, PDE (treatable inborn error of metabolism) should be considered in children with neurological sequelae of presumed HIE, strabismus, optic atrophy, and defective vision.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
- 1.Kavitha V, Heralgi MM. Analysis of regular screening of children in schools for the blind-Its importance. Indian J Ophthalmol. 2021;69:2540. doi: 10.4103/ijo.IJO_1836_21. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Al-Saman A, Rizk TM. A case of extreme prematurity and delayed diagnosis of pyridoxine dependent epilepsy. Neurosciences. 2012;17:371–3. [PubMed] [Google Scholar]
- 3.Chinta S, Wallang BS, Sachdeva V, Gupta A, Patil-Chhablani P, Kekunnaya R. Etiology and clinical profile of childhood optic nerve atrophy at a tertiary eye care centre in South India. Indian J Ophthalmol. 2014;62:1003–7. doi: 10.4103/0301-4738.145996. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Karnebeek CDM, Tiebout SA, Niermeijer J, Poll-The BT, Ghani A, Coughlin IICR, et al. Pyridoxine dependent epilepsy:An expanding clinical spectrum. Pediatr Neurol. 2016;59:6–12. doi: 10.1016/j.pediatrneurol.2015.12.013. [DOI] [PubMed] [Google Scholar]
- 5.Rahman S, Footitt EJ, Varadkar S, Clayton PT. Inborn errors of metabolism causing epilepsy. Dev Med Child Neurol. 2013;55:23–36. doi: 10.1111/j.1469-8749.2012.04406.x. [DOI] [PubMed] [Google Scholar]