Diaphragmatic dysfunction as the presenting symptom in neuromuscular disorders: A retrospective longitudinal study of etiology and outcome in 30 German patients

Diaphragmatic dysfunction is well-known in advanced stages of neuromuscular disorders. However, data on its presence as the presenting symptom in neuromuscular disorders is scarce. The goal of this retrospective longitudinal study was to evaluate the etiology and clinical outcome in patients, in whom uni- or bilateral diaphragmatic dysfunction was primarily diagnosed, before a specific neuromuscular disease was found. Patients with critical illness neuropathy/myopathy were excluded from this study. Analysis of the medical records of two tertiary referral centers for patients with neuromuscular diseases identified 30 corresponding patients with diaphragmatic dysfunction (17 unilateral; 13 bilateral). Phrenic neuropathy was found in 28 patients, one patient suffered from myasthenia gravis and another from Pompe disease. In 71% of patients with phrenic neuropathy a definite diagnosis could be established (iatrogenic lesion; amyotrophic lateral sclerosis; neuralgic amyotrophy; neuroborreliosis; multifocal motor neuropathy; chronic inflammatory demyelinating neuropathy; post-polio syndrome; spondylosis affecting the nerve root C4/5; and diabetes mellitus). When excluding all 5 patients with amyotrophic lateral sclerosis and further 3 with no follow-up data from outcome analysis, full or partial recovery was seen in 23% or 50% of patients, respectively. Early respiratory and electrophysiological work-ups are mandatory to ascertain the diagnosis and etiology of diaphragmatic dysfunction and to initiate therapy and counseling.