A RARE CASE OF CHEMOTHERAPY-INDUCED PHRENIC NEUROPATHY

Abstract

SESSION TITLE: Tuesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM INTRODUCTION: Chemotherapy induced peripheral neuropathy is a well described sequela of several chemotherapeutic agents, which can lead to permanent symptoms and disability in up to 40% of cancer survivors1. Large sensory nerve fibers are most commonly affected; however, motor neuropathy can also develop. Up to 20 to 40% of patients receiving platinum compounds have been reported to experience sensory neurotoxicity, however motor neuropathy is uncommon. Furthermore, motor impairment of the phrenic nerve has rarely been encountered with only four prior case reports being found in the literature2,3,4,5. Only one possible case of platinum associated phrenic neuropathy has been described4. CASE PRESENTATION: A 34 year old male with a metastatic right testicular cancer presented with a three month history of progressive dyspnea on exertion. He had undergone right orchiectomy & had received 4 cycles of chemotherapy with bleomycin, cisplatin and etoposide. Symptoms were first noted during the final cycle of chemotherapy, which continued to progress over the next two months. Physical exam was notable for clear lungs on auscultation with no evidence of diaphragmatic paradox. Pulmonary function tests showed a restrictive pattern, with low maximal inspiratory and expiratory pressures (Figure 1). Repeat CT showed bibasilar atelectasis with low lung volumes on scout film when compared to prior chest x-ray (Figure 2). Fluoroscopic sniff evaluation demonstrated evidence of right greater than left diaphragmatic weakness, and phrenic nerve EMG, while within normal limits, was notable for asymmetric right side predominant nerve conduction discrepancies consistent with possible fascicular phrenic neuropathy. Constellation of findings was most concerning for drug induced phrenic neuropathy leading to diaphragmatic weakness. DISCUSSION: Chemotherapy induced phrenic motor neuropathy leading to diaphragmatic weakness or paralysis is a rarely described phenomenon. Of the four prior case reports, two were associated with vincristine, which is more associated with motor neuropathies2,3. Only one these case reports described a phrenic neuropathy associated with a regimen that included a platinum based agent4. However, this case also involved radiation therapy, which has been associated with phrenic neuropathy in prior case reports. Here we describe a clear case of platinum associated phrenic neuropathy leading to symptomatic diaphragmatic weakness. CONCLUSIONS: Platinum based chemotherapy is a possible cause of phrenic neuropathy leading to diaphragmatic impairment. Reference #1: Park SB, Goldstein D, Krishnan AV, Lin CSY, Friedlander ML, Cassidy J, Koltzenburg M, Kiernan MC. Chemotherapy-induced peripheral neurotoxicity: A critical analysis. Ca Cancer J Clin. 2013;63: 419-437 Reference #2: Stevens WW, Sporn PHS. Bilateral diaphragm weakness after chemotherapy for lymphoma. Am J Respir Crit Care Med. 2014;189(7):12 Reference #3: Gilliland P, Holguin M. Phrenic nerve paralysis due to vincristine. Leuk Lymphoma. 2007;48(12): 2452-2453 DISCLOSURES: No relevant relationships by Vivek Iyer, source=Web Response No relevant relationships by Mark Norton, source=Web Response