Recurrent Pneumonia in a Patient With Oculopharyngeal Muscular Dystrophy (OPMD) due to GCN Expansion in the PABPN1 Gene: A Diagnostic Challenge

Abstract

Oculopharyngeal muscular dystrophy (OPMD) is a rare neuromuscular disorder that may present with respiratory complications, yet it is seldom considered in this context.

We report a 68-year-old institutionalized man, independent in daily activities, who presented with exertional dyspnea, fever, productive cough, hypoxemia, and bibasilar crackles. Laboratory tests showed normocytic anemia, lymphopenia, and elevated C-reactive protein; chest imaging revealed an alveolo-interstitial pattern. Despite empirical antibiotics, he experienced recurrent relapses with fever and radiological worsening. Immunological studies showed T-cell lymphopenia, reduced NK cells, and isolated anti-SSA/Ro52 positivity. Pneumocystis jirovecii was detected in an initial bronchoalveolar lavage but not confirmed, and no significant immunosuppression was found. Later, bilateral ptosis, proximal weakness, and oropharyngeal dysphagia prompted neuromuscular evaluation. Muscle MRI showed symmetric atrophy, and quadriceps biopsy revealed rimmed vacuoles. Genetic analysis confirmed OPMD (GCN repeat expansion in PABPN1). This case emphasizes the need to consider neuromuscular causes of recurrent pneumonia and the value of multidisciplinary, genetic-based diagnosis.