Diaphragmatic weakness; Phrenic nerve palsy; Respiratory muscle weakness
Definition and Characteristics
Inspiratory muscle weakness that results from any disease process affecting the diaphragm or the neural structures that innervate the diaphragm. Disorders of the lower motor neuron (Phrenic nerve, neuromuscular junction or muscle) are most common, but diaphragmatic paralysis may also result from injury to upper motor neuron pathways.
There are no epidemiological studies, in part because diaphragmatic paralysis is not a unitary disease entity, but rather a clinical syndrome with many diverse causes.
Diaphragmatic paralysis may be associated with a number of different genetic disorders including the hereditary motor and sensory neuropathies (Charcot-Marie Tooth disease)  and the metabolic myopathies, notably acid maltase deficiency [2,3]. Although diaphragmatic weakness may be found in several of the autosomal dominant