Uhthoff's phenomenon in multiple sclerosis and neuromyelitis optica

Area of Science:

• Neuroimmunology
• Clinical Neurology
• Ophthalmology

Background:

• Uhthoff's phenomenon is a transient worsening of neurological symptoms triggered by increased body temperature.
• This phenomenon is commonly associated with demyelinating diseases like multiple sclerosis (MS).
• Its occurrence in neuromyelitis optica-related disorders (NMOrd) requires further investigation.

Purpose of the Study:

• To compare the incidence and clinical characteristics of Uhthoff's phenomenon in Japanese patients diagnosed with MS versus NMOrd.
• To determine if there are significant differences in the presentation of heat sensitivity between these two neurological conditions.

Main Methods:

• A cohort of 135 consecutive patients with MS and NMOrd were surveyed.
• Participants were asked about experiencing exacerbated neurological symptoms following a rise in body temperature.
• Data from 54 MS patients and 37 NMOrd patients were analyzed.

Main Results:

• Uhthoff's phenomenon was reported by 48.1% of MS patients and 54.1% of NMOrd patients.
• The incidence of Uhthoff's phenomenon was statistically similar between the MS and NMOrd groups.
• Motor and sensory symptoms were more prevalent than visual symptoms in both disease cohorts.

Conclusions:

• The incidence of Uhthoff's phenomenon is comparable in Japanese patients with MS and NMOrd.
• Clinical features, particularly the predominance of motor and sensory over visual symptoms, are similar in both conditions regarding heat sensitivity.
• These findings suggest a shared susceptibility to temperature-induced symptom exacerbation in these distinct neuroinflammatory diseases.