A Telephonic Single Breath Count Test for Screening of Exacerbations of Myasthenia Gravis: A Pilot Study

Muscle Nerve. 2020 May 24. doi: 10.1002/mus.26987. Online ahead of print.

Abstract

Background: Patients with myasthenia gravis (MG) may experience worsening symptoms outside of a clinical setting. A method of diagnosing and triaging such individuals would be valuable. This study gauged the viability of a nurse-administered single breath count test (SBCT) over the telephone for assessing MG exacerbations.

Methods: This was a retrospective, single-center review of a pilot study of 45 telephone calls from patients with MG who had worsening baseline symptoms. SBCTs were administered over the telephone to patients by trained nurses. Patients with a breath count of 25 or less were sent to the emergency department.

Results: Using a cutoff count of 25, the nurse-administered telephonic SBCT had a positive predictive value of 71%, sensitivity of 80%, and specificity of 60% in diagnosing an MG exacerbation.

Conclusions: SBCT administered by trained nurses by means of telephone may be a useful screening tool for assessing decreased respiratory function in patients with MG.

Keywords: SBCT; breath count; exacerbation; myasthenia gravis; myasthenic crisis; telemedicine.