Subclinical peripheral neuropathy in stable middle-aged patients with chronic obstructive pulmonary disease

INTRODUCTION: Presently, there are few studies addressing the subject of peripheral neuropathy in patients with chronic obstructive pulmonary disease (COPD). Consequently, there is a dearth of evidence and awareness of subclinical neuropathy in stable COPD patients with no significant hypoxaemia, particularly in the age group of 40-60 years. The present study was designed to evaluate the subclinical peripheral neuropathy in this study group. METHODS: 60 subjects were included in the study. The COPD group comprised 30 male smokers with stable COPD, aged between 40 and 60 years and with no clinical neuropathy; and 30 age-matched healthy male volunteers served as the control group. The following nerves were evaluated for latency, amplitude and conduction velocity: for motor nerve conduction - median nerve, ulnar nerve, and common peroneal nerves; and for sensory nerve conduction - median nerve, ulnar nerve, and sural nerves. RESULTS: Five out of 30 COPD patients had peripheral nerve impairment on electrophysiological evaluation. In these patients, we found decreased amplitude and conduction velocity in all examined sensory nerves; however, the conduction velocity was found to be more than 70 percent of the predicted value. These findings were suggestive of predominantly sensory (with milder involvement of motor nerves) axonal polyneuropathy. CONCLUSION: We observed five out of 30 COPD patients to have predominantly sensory axonal peripheral neuropathy. These five COPD patients had significantly higher consumption of cigarettes, longer duration of illness and advanced airflow obstruction when compared to COPD patients with no peripheral neuropathy.