Parker Nguyen, MD
Resident Physician
NewYork-Presbyterian
New York, New York, United States
Ymi Ton, MD, MS
Resident Physician
NewYork-Presbyterian
New York, California, United States
Jack Haberl, MD, MBA
Resident Physician
NewYork-Presbyterian
New York, New York, United States
Kuntal Chowdhary, MD
Attending Physician
NewYork-Presbyterian
New York, New York, United States
Christopher J. Visco, MD
Attending Physician
NewYork-Presbyterian
New York, New York, United States
Phrenic nerve entrapment secondary to brachial neuritis
Case Description:
A 41-year-old man with history of cannabinoid hyperemesis syndrome (CHS) was referred to the sports medicine clinic with chronic exertional shortness of breath (SOB) that began one year ago after an episode of CHS requiring hospitalization. He also reported right-sided neck pain before the onset of SOB throughout the past year. Recent fluoroscopic sniff test and chest x-ray demonstrated elevation and decreased movement of the right hemidiaphragm. During the evaluation, ultrasound of the right neck, axilla, and arm revealed post-foraminal dilation of the upper trunk (C5-C6) with an area of focal enlargement and notching of the phrenic nerve (PN) over the thyrocervical trunk, just proximal to the upper trunk. Subsequent MR neurogram revealed an hourglass constriction involving the PN at the C7 vertebral body.
Discussions:
This case emphasizes the utility of diagnostic ultrasound in the evaluation of complex neurologic pathologies. Evidence of focal entrapment of the PN was seen on both ultrasound and MR neurogram. The notable enlargement of the C5/C6 nerve roots and upper trunk on ultrasound are common findings of brachial neuritis (BN). His dyspnea was likely caused by PN entrapment in the setting of BN. His right neck pain and BN may have been sequelae of his CHS episode one year prior. He was referred to cardiothoracic surgery and ultimately received surgical decompression of the right PN. These sonographic findings helped guide the referring thoracic surgeon during surgical intervention.
Recent studies have shown that ultrasound is useful for providing diagnostic clues of BN. This case is novel because it is the first to report the use of ultrasound in the diagnostic workup of PN entrapment secondary to BN.
Conclusions:
Diagnostic ultrasound can guide the diagnosis and surgical intervention of PN entrapment and BN causing chronic exertional dyspnea and right neck pain.
