title: Multiple sclerosis disease progression and paradichlorobenzene: a tale of mothballs and toilet cleaner.
abstract: OBJECTIVE
  Environmental factors are thought to be critical in the initiation and perpetuation of multiple sclerosis disease activity.
  
  
  METHODS
  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
  This case illustrates that environmental causes for neurological deterioration should be investigated in patients with multiple sclerosis 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.
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Hession
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Vibhash
authors.initials: V
authors.lastname: Sharma
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Spiegel
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Christine
authors.initials: C
authors.lastname: Tat
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Daniel George
authors.initials: DG
authors.lastname: Hwang
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Marisara
authors.initials: M
authors.lastname: Dieppa
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Zakraus
authors.initials: Z
authors.lastname: Mahdavi
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Ellen
authors.initials: E
authors.lastname: Marder
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas.
authors.forename: Olaf
authors.initials: O
authors.lastname: Stüve
mesh_terms: D000328:Adult; D002273:Carcinogens / Q000008:administration & dosage*; D002722:Chlorobenzenes / Q000506:poisoning*; D003902:Detergents / Q000506:poisoning*; D018450:Disease Progression; D005260:Female; D006801:Humans; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000139:chemically induced / Q000175:diagnosis*
chemical_list: D002273:Carcinogens; D002722:Chlorobenzenes; D003902:Detergents; C018511:4-dichlorobenzene