Bilateral phrenic neuropathy responsive to intravenous immunoglobulin treatment

Paolo Ripellino,Claudio Gobbi,Marco Pons,Mikael Gian Andrea Izzo

doi:10.1177/2514183x19891606

Abstract

The aetiology of phrenic neuropathy is often unknown, but immune mechanisms may play a role. In a typical case of bilateral phrenic neuropathy with paradoxical breathing (video), an inflammatory pathogenesis was suggested by prolonged distal latency of phrenic nerve compound muscle action potentials in nerve conduction studies and a clear-cut albumin-cytologic dissociation. This encouraged us to treat the patient with a standard dose of intravenous immunoglobulin. After obtaining a strong improvement at spirometry, we repeated the second cycle of intravenous immunoglobulin and observed normalization of symptoms within few weeks and no relapse after 3 years. This case suggests that lumbar puncture should be performed in the acute phase of phrenic neuropathies to detect potential responders to immunomodulatory treatment.

Highlights

The diaphragm is innervated bilaterally by the phrenic nerve and is the main respiratory muscle
While unilateral diaphragm paralysis is usually asymptomatic, a bilateral palsy often leads to orthopnoea and dyspnoea, especially during exercise or when lying supine, and a typical sign known as ‘paradoxical breathing’
This sign can be better appreciated in supine position and corresponds to the paradoxical inward motion of the abdomen during inspiration due to the contraction of accessory inspiratory muscles while the abdominal wall moves inwards (Supplemental Video)

Summary

Introduction

The diaphragm is innervated bilaterally by the phrenic nerve and is the main respiratory muscle. It is important to compare the pulmonary function tests obtained in upright and supine position, because in bilateral phrenic neuropathy, there is typically moderate-to-severe restrictive dysfunction (30–50% of the predicted value for total lung capacity) that becomes more severe when the patient is supine. This decline of function in supine position is due to the cephalad displacement of abdominal contents in concert with ineffective activity of the accessory inspiratory muscles and may account for a decrease in vital capacity up to 50%. The patient had no relapse after more than 36 months of follow-up

Discussion

Findings

Declaration of conflicting interests