Vocal Cord Paralysis and Hypercapnic Respiratory Failure in a Patient with Familial Amyloidotic Polyneuropathy

We herein report a patient case with familial amyloidotic polyneuropathy (FAP) who presented with vocal cord paralysis (VCP). A 60-year-old man with FAP (Gly89Gln) presented with hoarseness and snoring for the previous two years. A chest X-ray demonstrated cardiomegaly and bilateral diaphragmatic elevation. The findings of a restrictive pattern on spirometry and daytime hypercapnia were consistent with respiratory muscle weakness related to neuropathy [ forced expiratory volume (FEV1): 38%, forced vital capacity (FVC): 39%, FEV1/FVC: 77, partial pressure of arterial oxygen (PaO2): 80 mmHg, partial pressure of carbon dioxide in arterial blood (PaCO2): 52 mmHg]. An ear-nose-throat examination showed VCP. Polysomnography revealed severe obstructive sleep apnea (OSA). FAP may cause OSA by VCP and hypercapnic respiratory failure by respiratory muscle weakness. Therefore, an ear-nose-throat examination, spirometry, arterial blood gases analysis and polysomnography are important for these patients.