Two Cases of Severe Type 2 Respiratory Failure Associated with Diffuse Idiopathic Skeletal Hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory process characterized by hyperostosis at tendon insertions and around joint capsules and ossification of the anterior longitudinal ligament of the spine. The flexibility of the spinal column is reduced in DISH and affects the movement of the thorax, leading to restrictive ventilatory function. In this report, we describe the first two cases of severe type 2 (hypercapnic) respiratory failure associated with DISH. Two older men presented with histories of shortness of breath. Radiography of the spine revealed DISH with coexisting ankylosis of the costovertebral joints. The patients' thoracic motion was severely restricted, reducing the mechanism of lung expansion to diaphragm contraction only. Both patients required non-invasive positive-pressure ventilation therapy to cope with their conditions. Our report sheds light on the risk of potentially life-threatening respiratory manifestations of DISH among older adults.