Diaphragm paralysis causing ventilatory failure in an adult with the rigid spine syndrome.

A syndrome consisting of a rigid spine and myopathy predominantly affecting proximal limb muscles has been previously described in children, and as with most neuromuscular disorders, the respiratory muscles appear to be affected only at an advanced stage in the disease. We describe an adult male with this syndrome who presented with ventilatory failure caused by severe respiratory muscle weakness and who demonstrated profound nocturnal arterial oxygen desaturation, particularly during rapid eye movement sleep. Treatment with negative pressure ventilation initially resulted in only modest improvements in symptoms, blood gas tensions, and nocturnal desaturation. The cause of this only partial improvement was upper airway obstruction provoked by the mode of ventilatory support used. After tracheostomy there was a dramatic and sustained improvement in symptoms and blood gas tensions and complete abolition of nocturnal arterial oxygen desaturation. This is the first report of an adult with the rigid spine syndrome presenting with ventilatory failure and cor pulmonale due to severe respiratory muscle weakness.