Explanation for the New Brunswick Mystery Illness Proposed in New Article

The cluster of cases initially identified as the New Brunswick neurological syndrome of unknown cause (NSUC) and thought to constitute a novel neurologic disorder is likely to be a combination of well-known and misdiagnosed disorders, according to results of a cross-sectional study published in JAMA Neurology. Following a reassessment of 25 patients provisionally diagnosed with New Brunswick NSUC, no new or unknown disease entity was identified, with patients instead receiving diagnoses of neurodegenerative disorders, functional neurological disorders, traumatic brain injury (TBI), and metastatic cancer, among other conditions. This finding counters the widely publicized speculation about a potentially fatal new disease caused by an environmental toxin, prion, or pathogen.

The study was conducted at 2 hospitals—the Horizon Health Network in New Brunswick, Canada and the University Health Network in Ontario, Canada—and included 25 individuals from a pool of 222 cases of New Brunswick NSUC submitted to Public Health New Brunswick (PHNB). Participants received an independent clinical evaluation (n=14) or postmortem autopsy evaluation (n=11) for neuropathological assessment.

• All 25 participants received a diagnosis of a known neurologic disorder.
• Diagnoses included neurodegenerative disorders (n=11), non-neurodegenerative disorders (n=10), and 1 patient with primary psychiatric illness and no significant pathologic abnormalities.
• The probability of the existence of a new disease was <.001, with a 95% CI of 87% to 100%.

According to the authors of this study, these results demonstrate the importance of a second, independent evaluation for complex conditions and also highlight the need for clear education and communication to patients.