In hospitalized patients, an elevated hemidiaphragm on chest x-ray is not a rare finding and is frequently asymptomatic. It has many potential causes, including lobar collapse or surgical resection of the lung, diaphragmatic eventration, distention of stomach or colon, or phrenic nerve paralysis (1).
Among patients with a paralyzed hemidiaphragm, damage to the phrenic nerve caused by surgery (e.g. cardiac), mediastinal tumors, cervical spine pathology, diabetes, autoimmune (e.g. vasculitis) and infectious causes (e.g. herpes zoster and polio viruses) are often cited as potential causes; most may be idiopathic, however (1,2,3).
Chest x-ray has a high negative predictive value (93%) but a poor positive predictive value for diagnosis of hemidiaphragm paralysis (1). When in doubt, the fluoroscopic “sniff” test should be used for confirmation.
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1. Chetta A, Rehman AK, Moxham J, et al. Chest radiography cannot predict diaphragm function. Resp Med 2005;99:39-44
2. Curtis J, Nawarawong W, Walls J, et al. Elevated hemidiaphragm after cardiac operations: incidence, prognosis, and relationship to the use of topical ice slush. Annals of Thoracic Surgery 1989;48:764-8.
3. Crausman RS, Summerhill EM, McCool FD. Idiopathic diaphragmatic paralysis: Bell’s palsy of the diaphragm? Lung 2009;187:153-157.
Contributed by Ethan Balgley, Harvard Medical Student
Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis or its affiliate healthcare centers. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!