A male in his 40s faced social embarrassment due to body malodor. A case of trimethylaminuria
A 41-year-old male presented with complaints of fishy odor from his body since the age of 13 years. The patient had received comments regarding his body malodor from his friends.
However, despite multiple comments by his friends, the patient himself and his family were not able to detect this malodor. Moreover, this emotionally disturbed the patient as it caused him considerable social embarrassment.
He reported using topical antiperspirants, however, those did not help much.
Past medical history revealed reflux esophagitis, a duodenal ulcer, and a minor head injury. Past surgical history revealed arthroscopy and meniscectomy and corneal foreign-body removal. Moreover, he also had a history of panic attacks for which he was taking propranolol hydrochloride.
The patient’s parents were cousins and he had 2 siblings. His brother had similar complaints whereas his sister had no such symptoms.
Initial examination revealed no malodor or skin abnormalities. However, the doctors had a clinical suspicion of trimethylaminuria (fish-odor syndrome), they evaluated him further.
His laboratory investigations revealed urinary trimethylamine (TMA) level of 14.7 μmol/mmol of creatinine while he was taking his usual diet. The TMA-N-oxide level was 34 μmol/mmol of creatinine, and the TMA/TMA-oxidase ratio was 0.43. Therefore, with the significantly high excretion of TMA coupled with a raised TMA/TMA-oxidase ratio, he received a diagnosis of primary trimethylaminuria.
Trimethylaminuria is a rare metabolic disorder inherited as an autosomal recessive trait. It results from a defective hepatic microsomal oxidase enzyme system responsible for metabolizing TMA. Individuals suffering from this disorder emit an odor similar to that of decaying fish.
With the diagnosis of trimethylaminuria, the doctors referred the patient to a dietitian for advice on foods that contain low amounts of choline and lecithin.
At the 2-month follow-up, his TMA level was 9.6 μmol/mmol of creatinine. Since the level has lowered it reflected successful dietary modification. However, his urinary TMA level increased to 102.8 μmol/mmol of creatinine; the TMA-N-oxide level was 263.4 μmol/mmol of creatinine, and the TMA/TMA-N-oxide ratio was 0.39 when investigations were subsequently repeated, possibly a reflection of dietary relaxation.
Therefore, the doctors prescribed him 500 mg of oral metronidazole for 10 days as a trial. With metronidazole, there was some improvement. Besides symptomatic improvement, the best improvement was that the patient was able to communicate with his family members and friends about the condition.
Source: Arseculeratne G, Wong AKC, Goudie DR, Ferguson J. Trimethylaminuria (Fish-Odor Syndrome): A Case Report. Arch Dermatol. 2007;143(1):81–84. doi:10.1001/archderm.143.1.81