Volatile Gases Of Diarrhea May Diagnose Infectious Cause

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Laurie Barclay, MD

Dec. 31, 2003 — It may be possible to diagnose the cause of

infectious diarrhea from the accompanying volatile gases, according

to the results of a study published in the January issue of Gut.

" The microbiological diagnosis of infectious diarrhoea may take

several days using conventional techniques, " write C. S. J. Probert,

from the Bristol Royal Infirmary in the U.K., and

colleagues. " Depending on the patient's circumstances, the results

of a diagnostic delay is likely to range from lost productivity to

prolonged hospitalisation or death. There is a pressing need to make

a rapid accurate diagnosis in all patients. "

The investigators collected stool samples from 35 patients

hospitalized with infectious diarrhea and from six healthy controls,

and they used solid phase microextraction (SPME) from a headspace as

well as gas chromatography and mass spectroscopy (GC-MS) to extract

and analyze volatile gases.

The main causes of infectious diarrhea were associated with

characteristic patterns of gas composition: furan species without

indoles in Clostridium difficile, ethyl dodecanoate in rotavirus,

ammonia without ethyl dodecanoate in other enteric viruses, and the

absence of hydrocarbons and terpenes in Campylobacter infection.

Because these findings may be method-dependent, the authors suggest

that changing the SPME fiber and the protocol for GC-MS could reveal

even more sensitive and specific markers and could improve the speed

of vapor analyses.

" These results could be the basis of rapid near patient diagnosis of

infectious diarrhoea, " they write. " It remains to be seen whether

this approach can be applied to non-infectious gastrointestinal

disorders; this is an area of active exploration.... The development

of an inexpensive device capable of near patient testing will hasten

diagnosis, saving time and money. "

The United Bristol Hospitals' Charitable Trust funded this study.

Gut. 2004;53:58-61

Reviewed by D. Vogin, MD