Patients who are discovered to have a vocal cord palsy with no obvious cause on history or examination routinely undergo investigations to exclude an underlying pathology. Cross-sectional imaging of the relevant recurrent laryngeal nerve is required, but considerable variability has been noted in clinical practice with regard to the use of blood tests. This paper reports the results of a retrospective chart review for 231 patients with vocal fold paralysis managed by the senior author. A comprehensive battery of laboratory tests was routinely performed as part of their work-up, and the study sought to determine the prevalence of abnormal blood test results in this cohort relative to the general population.
Statistically significant differences were noted in abnormal blood test results for white blood count (high or low), syphilis serology, Lyme disease serology and tests for myasthenia gravis.
No significant differences were noted for haemoglobin, TSH, anti-TPO antibodies, fasting blood glucose, ANA or rheumatoid factor. The authors acknowledge that the abnormal blood test results found in this cohort do not necessarily imply causality. Nevertheless, Lyme disease, syphilis and myasthenia gravis are all documented causes of vocal cord palsy that are potentially reversible with appropriate medical treatments. As such, testing for these conditions should be considered for all patients presenting with a vocal cord palsy in the appropriate clinical context.