Etiologic Profile of Spastic Quadriplegia in Children

Correspondence Etiologic Profile of Spastic Quadriplegia in Children To the Editor: Regarding “Etiological Profile of Spastic Quadriplegia in Children” by Venkateswaran and Shevell (Pediatr Neurol 2007; 37:203-208), I was attracted by the title, but greatly disappointed by the contents, of this article. The authors appear to confuse pathology with etiology. In their Table 2, 26 of the 82 “etiologies” appear to refer to the pathologic substrate of spastic quadriplegia (periventricular leukomalacia, malformation, intraventricular hemorrhage, and hydrocephalus), rather than any etiological agent. It is hardly surprising that the proportion “unexplained” is so small, or that the cause of almost all preterm cases is labeled as “explained.” They are not alone in this confusion: in their Discussion, Edebol-Tysk is said to identify microcephaly as a prenatal cause [1]. If microcephaly were present at birth, it would suggest a prenatal cause, but it is a sign and not a cause in itself. I do not understand what is meant by “predictors of etiological determination” (Table 4), but I am sure that the inclusion of all births before 37 weeks of gestation in “perinatal complications” renders this table fairly meaningless. The premature births in these cases must have been a result of some prenatal complication (unless they had unknown lengths of gestation combined with poor obstetric judgment), which may or may not have been compounded by further perinatal complications. Articles such as these suggest that the etiologies of childhood disability are known, and are largely perinatal, whereas the causal pathways to the majority of cases are very poorly understood, but are thought to include many prenatal factors. Eve Blair, PhD Centre for Child Health Research University of Western Australia West Perth, Western Australia, Australia

Reference [1] Edebol-Tysk K, Hagberg B, Hagberg G. Epidemiology of spastic tetraplegic cerebral palsy in Sweden: II. Prevalence, birth data and origin. Neuropediatrics 1989;20:46-52.

We concur with Dr. Blair that “microcephaly” is a sign and not an etiologic cause. We do not make this error in our article, and we do not endorse it in any way in other publications. Regarding “predictors of etiologic determination,” we suggest that the identification of these factors may increase a clinician’s success of finding a possible underlying etiology. These factors, features, or predictors can then be utilized to guide the physiciandirected evaluation and workup. Premature birth can indeed be considered a perinatal complication. By definition, it occurs only at the moment of actual birth, and cannot be accurately foretold (hence perinatal in timing). Its occurrence results in increased scrutiny from a medical perspective, even if the subsequent course turns out to be entirely benign. Thus it is considered a “complication.” In our article, we do not suggest, as Dr. Blair puts forward, that “the etiology of childhood disability is known.” Indeed, we emphasize in our discussion that one in six children with spastic quadriplegia still has an unknown cause, despite significant neuromotor impairment. Future efforts, as we noted in the text, should be directed at identifying causations in this significant subset, and at identifying the underlying mechanisms for stroke and cerebral dysgenesis. In addition, we did not state that the etiology of childhood disability is “largely perinatal,” as suggested by Dr. Blair. In the setting of spastic quadriplegia, the two major causes, responsible collectively for less than half of the documented cases, indeed occur in the perinatal period. These causes are intrapartum asphyxia and periventricular leukomalacia. Their occurrence perinatally offers the potential for future therapeutic efforts that may lessen subsequent morbidity. In addition, it is evident that many perinatal occurrences have their root cause in a prenatal disposition that somehow enhances perinatal vulnerability. We appreciate the comments of Dr. Blair, and hope that we have clarified matters to a fuller extent. Michael Shevell, MD, CM Department of Neurology Department of Neurosurgery and Pediatrics McGill University Division of Pediatric Neurology Montreal Children’s Hospital Sunita Venkateswaran, MD Division of Pediatric Neurology Montreal Children’s Hospital Montreal, Quebec, Canada Reference

Response: We are sorry that Dr. Blair is disappointed by the contents of our article. We think that much of her disappointment stems from a difference in conceptualization of the word “etiology.” Throughout publications from our institution addressing various aspects of etiology in neurodevelopmental disabilities, the following definition of etiology (first put forward by Schaeffer and Bodensteiner) has been employed: “a specific diagnosis that can be translated into useful clinical information for the family, including providing information about prognosis, recurrent risk and preferred modes of available therapy” [1]. For those engaged in active clinical practice, this conceptualization is pragmatic and relevant, and is of considerable importance to the patient.

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[1] Schaefer GB, Bodensteiner JB. Evaluation of the child with idiopathic mental retardation. Pediatr Clin North Am 1992;929-943.

Clarification of the Term “Status Gelasticus” and Treatment and Prognosis of Gelastic Seizures To the Editor: Shahar et al. describe a cohort of only 10 Israeli children with gelastic seizures, and discuss the outcomes and treatments of this clinical condition [1]. Based on the retrospective data from their small cohort of patients, they make some fairly dramatic, broad

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