What is the role of fluoroscopy in the workup of diaphragmatic paralysis?

Updated: Oct 10, 2018
  • Author: Justina Gamache, MD; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Answer

Because accessory muscle contraction may create the appearance of diaphragmatic movement, this study may mislead the physician when diagnosing bilateral diaphragmatic paralysis (see the image below).

Fluoroscopy of elevated left hemidiaphragm in a pa Fluoroscopy of elevated left hemidiaphragm in a patient with unilateral diaphragmatic paralysis. The diaphragm moves paradoxically upward during inspiration.

In fluoroscopic sniff testing, paradoxical elevation of the paralyzed diaphragm is observed with inspiration and confirms diaphragmatic paralysis (see the image below). [14] However, the sniff test is not very specific; 6% of normal persons exhibit paradoxical motion on fluoroscopy. [9] Due to compensatory respiratory strategies, apparently normal decent of diaphragms may also be seen with sniff test in bilateral diaphragmatic paralysis. [3]


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