Diagnosing additional problems in MSers on DMTs

What have mothballs got to do with MS? #MSBlog #MSResearch

“Wow, what an interesting case. It shows that MSers are not immune to other neurological disorders including neurotoxins. In fact MSers are more likely to suffer the ill effects of neurotoxins; MS reduces brain reserve therefore MSers are more susceptible to any drug, toxin or process that affects brain function. This includes side effects of drugs, head injuries or other age-related diseases for example stroke of Alzheimer’s disease. The MSer described below was not doing well on natalizumab and was found to be ingesting a neurotoxin; a very unusual neurotoxin at that.”

“I was taught at medical school to always take a step backwards and ask the question can it be anything else? In this case it was; it was not MS but a toxin. A clue was encephalopathy; this refers to a clinical syndrome characterized by clouding of consciousness. The latter is very rarely due to MS.”

Epub: Hession et al. Multiple Sclerosis Disease Progression and Paradichlorobenzene: A Tale of Mothballs and Toilet Cleaner. JAMA Neurol. 2013 Dec 16.

IMPORTANCE: Environmental factors are thought to be critical in the initiation and perpetuation of multiple sclerosis disease activity. 

OBSERVATIONS: We describe the case of a woman in her late 30s with a diagnosis of relapsing-remitting multiple sclerosis, who continued to accumulate neurological disability despite long-term natalizumab treatment. The patient continued to have visual symptoms, left leg weakness, and gait instability. In addition, she subacutely developed an encephalopathy. Our investigations revealed that the patient had a long-standing history of chewing on toilet bowl deodorizing cakes. The main ingredient in this product is 99.9% paradichlorobenzene, which is also used in mothballs. 

CONCLUSIONS AND RELEVANCE: This case illustrates that environmental causes for neurological deterioration should be investigated in MSers who display a rapidly progressive disease course and in whom potent pharmacotherapies fail. One possible cause is the ingestion of paradichlorobenzene-containing mothballs and toilet cleaners.

About the author

Prof G

Professor of Neurology, Barts & The London. MS & Preventive Neurology thinker, blogger, runner, vegetable gardener, husband, father, cook and wine & food lover.


  • If this report is correct then giving MSers alemtuzumab could prove catastrophic, no? Alemtuzumab can cause very serious and devastating secondary neurological disorders, hence why NICE and the FDA are very sceptical of its benefits.

    A very momentous rethink is in order.

  • Chewing on toilet bowl deodorizing cakes, seriously? I thought I couldn't be surprised, but this one did.My compliments to the doctor who was thorough enough to investigate.

  • Okay, I'll bite: Why does anyone chew on toilet bowl deodorizing cakes? Is that a form of pica? Which leads to my next question…is chewing on odd things one of MS's odd symptoms?

By Prof G



Recent Posts

Recent Comments