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ELECTRONIC ARTICLE:
Fermin Barrueto, Jr,, Helena H. Wang-Flores, Mary Ann Howland, Robert S. Hoffman, and Lewis S. Nelson
Acute Vitamin D Intoxication in a Child
Pediatrics 2005; 116: e453-e456 [Abstract] [Full text] [PDF]
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[Read P3R] Vitamin D intoxication - a second view
Jacek Lukaszkiewicz   (27 February 2006)

Vitamin D intoxication - a second view 27 February 2006
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Jacek Lukaszkiewicz,
Biochemistry
Mwdical University of Warsaw, Poland

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Re: Vitamin D intoxication - a second view

jacekluk{at}farm.amwaw.edu.pl Jacek Lukaszkiewicz

To the Editor.- Vitamin D intoxication although rare is unfortunately not the thing of the past and the existing cases call for a very specific treatment. Therefore I red with interest the paper by Barrueto et al (1) printed in September 2005 issue of Pediatrics and I have following comments:

The information about vitamin D metabolism given by Authors is inaccurate – sunlight does not metabolize vitamin D to active compounds – it is the liver which begins activation of vitamin (2). I think the reference the Authors cite here is not relevant. Another problem concerns the assessment of vitamin D status of the patient. Authors freely swap the names such as vitamin D and 25- hydroxyvitamin D whilst measuring only the concentration of the metabolite. Saying that Fig.1 presents “trends” of vitamin D concentrations is misleading – it shows only the 25-hydroxyvitamin D levels.

Are the Authors sure that their 25OHD assay kit is equally sensitive to 25OHD2 and 25OHD3? The maker’s website does not contain any information on that issue. Most of the antibody-based tests seriously underestimate the levels of 25-OHD2 (3). On his release from the hospital the patient could have his actual vitamin D status much higher than it was assessed with the kit. Statement that “the boy made a complete clinical recovery” sounds a bit optimistic, when the serum concentration of the factor which caused toxicity has not changed much during treatment, and considering the possible analytical error still might be even 10 times as high as the normal upper limit. At high concentrations 25OHD can interfere with vitamin D receptors disturbing mineral homeostasis at the body and cellular levels.

It seems to me, that treatment of vitamin D intoxication should involve some means of removing of the excess vitamin D. Fortunately human body with some pharmacological assistance can metabolize vitamin D to harmless, water soluble compounds which are readily disposable. Such treatments have already been tried with success resulting in a real “complete clinical recovery” (4,5).

References: 1. Barrueto F, Wang-Flores HH, Howland MA, Hoffman RS, et al. Acute vitamin D intoxication in a child. Pediatrics 2005;116:453-456 2. Holick MF. Sunlight and vitaminD for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr. 2004;80:1678S-1688S 3. Wootton AM. Improving the measurement of 25-hydroxyvitamin D. Clin Biochem Rev. 2005;26:33-36 4. Łukaszkiewicz J, Prószyńska K, Lorenc RS, Ludwiczak H. Hepatic microsomal enzyme induction: treatment of vitamin D poisoning in a 7 month old baby. Br Med J 1987;295:1173-1173 5. Iqbal SJ, Taylor WH. Treatment of vitamin D2 poisoning by induction of hepatic enzymes. Br Med J 1982;285:541-542

Yours, Prof. Jacek Lukaszkiewicz Medical University of Warsaw Pharmacy Faculty, Biochem. Dpt. Banacha 1 str., 02-097 Waszawa, POLAND

Conflict of Interest:

None declared