Fish-Odor Syndrome Presenting as Dysosmia

Abstract

We describe a patient who had perceived an unpleasant odor or taste for at least 20 years. Several other physicians had unsuccessfully treated her for infections, mucus membrane dryness and inflammation, chronic tonsillitis, and psychiatric disorders. Her workup at the State University of New York Health Science Center at Syracuse Olfactory Referral Center included a thorough history, examinations (including endoscopic studies of her nose, pharynx, and lungs), roentgenograms, taste testing, olfactory testing, and selective anesthesia of her chemosensory areas. The perception occurred only during exhalation, and appeared to be binasal. These findings, together with her morning mucus sample having a strong fishlike odor, prompted us to suspect a metabolic problem. Further testing at the Monell-Jefferson Chemosensory Clinical Research Center, Philadelphia, Pa, confirmed that she had trimethylaminuria. It is important to consider this and other treatable conditions when evaluating individuals with olfactory complaints.

Non‐Oral Etiologies of Oral Malodor and Altered Chemosensation

“…The persistent foul taste/odor reported by these patients may be due to the presence of trimethylamine; however, excess amounts of other volatiles in the saliva and lung air of these patients are also seen. 34 We could detect the odor of TMA on the saliva/sputum of these patients.…”

The scent of human diseases: a review on specific volatile organic compounds as diagnostic biomarkers

“…However, persons with trimethylaminuria have a reduced ability to oxidize trimethylamine into trimethylamine N‐oxide, which leaves trimethylamine unmetabolized in the body. This is then excreted in urine, sweat, breath, saliva and reproductive fluids and has a strong rotten fish‐like smell …”

Trimethylaminuria (Fish-Odor Syndrome)

“…Local causes of altered olfactory perception need to be excluded because trimethylaminuria has been reported in association with dysosmia. 28 Fishy odors may be perceived by individuals with cacosmia (ie, abnormal odors perceived by persons exposed to neutral odors). The main confirmatory test is the estimation of free urinary TMA excretion.…”