Eosinophilia-myalgia syndrome

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**Eosinophilia-myalgia syndrome**
*Classifications and external resources*
ICD-9	710.5
DiseasesDB	32044
eMedicine	derm/891

Eosinophilia-myalgia syndrome (EMS) is an incurable and sometimes fatal flu-like neurological condition that is believed to have been caused by ingestion of L-tryptophan supplements. Similar to regular eosinophilia, it causes an increase in eosinophil granulocytes in the patient's blood.

1 History
2 Recent developments
3 Reference
4 See also
5 External links

[edit] History

Eosinophilia-myalgia syndrome was first recognized after an outbreak of the condition in 1989. Epidemologists first traced the cause to consumption of a single brand of tryptophan supplement. There was some evidence that new batches of this brand had been improperly prepared. The bacterial culture used to synthesise tryptophan had recently been genetically engineered to greatly increase tryptophan production, and shortcuts had been taken in the purification process to reduce costs. For example, a purification step that used charcoal absorption to remove impurities had been modified to reduce the amount of charcoal used. It is possible that one or more of these modifications allowed new or greater impurities through the purification. The specific impurity (or impurities) responsible for the toxic effects was never firmly established, although several impurities were proposed as the cause, and their chemical structures determined. Regardless of the origin of the toxicity, tryptophan was banned from sale in the US, and other countries followed suit. In February 2001, the FDA loosened the restrictions on the marketing of tryptophan (though not on importation).

[edit] Recent developments

Recent research from FDA has shown that the association of EMS with the a specific brand of tryptophan supplement may be false (Smith & Garrett, 2005). Many brands of tryptophan supplements are now known to be associated with this medical condition, which may be caused by tryptophan interference with toxic histamine metabolism. It is suggested that histamine then accumulates and causes the EMS syndrome.

[edit] Reference

Smith MJ, Garrett RH. A heretofore undisclosed crux of eosinophilia-myalgia syndrome: compromised histamine degradation. Inflamm Res. 2005 Nov;54(11):435-50. See: [1]

Walker,Larry, Carl Edwin Lindgren, Penni Bolton. (1991). L-Tryptophan induced eosinophilia-myalgia syndrome. The Journal of the Royal Society of Health, Volume 111, Number 1: 29-30.