In May issue of the Journal, Mehta et al. report two brothers with neurogenic diabetes insipidus and skeletal fluorosis(1). They regard fluorosis as a complication of diabetes insipidus. Whereas the authors' presumption that the development of fluorosis in these two patients could have been hastened by their large intake of water with a high fluoride content, fluorosis cannot be called a "complication" of diabetes insipidus per se. It is very likely that these children would have developed fluorosis even if they did not have diabetes insipidus. There can be little doubt that screening of inhabitants in the village in Rajasthan where these patients came from would identify other cases of fluorosis. The term "complication" implies a cause and effect relationship. For example, pneumothorax is a complication of status asthmaticus and encephalopathy that of lead intoxication. In both instances the complication would not occur unless the primary condi- tion were present.

The authors go on. to mention a most uninformed statement that "Further, severe crippling deformities due to skeletal fluorosis has not been reported in the literature to the best of our knowledge". Severe bony deformities are in fact quite commonly seen is endemic fluorosis. This has been well documented in the literature including Indian Pediatrics(2). The expression "to the best of our knowledge" cannot be a substitute for an elementary literature search.
 

R.N. Srivastava,
Consultant Pediatric Nephrologist
 Apollo Indraprastha Hospital,
New Delhi 110 044,
India.

1. Mehta MN, Raghavan K, Gharpure VP, Shenoy R. Fluorisis- A rare complication of diabetes insipidus. Indian Pediatr 1998; 35: 463-467.

2. Moudgil A, Srivastava RN, Vasudev A, Bagga A, Gupta A. Fluorosis with crippling skeletal deformities. Indian Pediatr 1986; 23: 767-773.