A 60-year-old paraplegic man came to the emergency department with a 1-day history of chest pain and shortness of breath. Physical exam revealed tachycardia, heart sounds (heard best on the right), and the presence of bowel sounds in his left hemithorax.

The patient’s intermediate probability for pulmonary embolism prompted a computed tomography of the chest (Figure 1). He was subsequently diagnosed with a non-ST-segment elevation myocardial infarction.

Unilateral diaphragmatic paralysis is usually asymptomatic in sedentary individuals and is frequently discovered incidentally. The most common causes are trauma, surgery, tumours, aortic aneurysm, herpes zoster, pleurisy, and diabetic neuropathy though occasionally it is idiopathic. More active patients may present with orthopnoea or exertional dyspnoea once they develop the unilateral paralysis.

Since our patient was wheelchair-bound due to his paraplegia, he was asymptomatic until he developed another condition which caused dyspnoea. The diagnosis can be made with the conventional chest radiographs (Figure 2) and confirmed with a fluoroscopic or ultrasound sniff test with a sensitivity of 90%.

Unilateral diaphragmatic paralysis usually does not require treatment unless it causes significant symptoms and its prognosis depends on the underlying cause. The only treatment available is surgical or thoracoscopic plication of the paralyzed diaphragm.

Author information: Gerson D Valdez, Internal Medicine Resident, East Tennessee State University, Johnson City, Tennessee, USA; Roger D Smalligan, Assistant Professor of Medicine, East Tennessee State University, Johnson City, Tennessee, USA

Correspondence: Gerson D Valdez MD, Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37604, USA. Email: sondavis92000@yahoo.com