False positive perfusion lung scintiscans in tetraplegic patients: A case series

An accurate diagnosis of pulmonary embolism is essential to prevent excessi ve morbidity and mortality from either inappropriate therapy or failure to institute anticoagulation. The diagnosis of pulmonary embolism in tetrapleg ic spinal cord injury patients is complicated by frequent inability to perf orm the ventilation portion of the ventilation-perfusion scintiscan (V/Q sc an) and by controversy regarding classification of defects on perfusion-onl y scans, as well as by coexisting pulmonary disease, systemic illness, rela ted injuries, and the tendency for tetraplegic patients to have unexplained fever. This report describes three tetraplegic ventilator-dependent patien ts with hypoxic respiratory failure and normal chest radiographs who had la rge defects on perfusion-only lung scans. Ventilation scintiscans were not performed because the patients were ventilator-dependent with tracheostomie s. Pulmonary angiography findings were normal in all patients, and all thre e responded to aggressive pulmonary toilet. Even large defects on perfusion -only scans despite normal chest radiographs should not be used to establis h a diagnosis of pulmonary embolism in tetraplegic patients, and further di agnostic imaging is warranted. (C) 1999 by the American Congress of Rehabil itation Medicine and the American Academy of Physical Medicine and Rehabili tation.