Failing phrenics

Abstract

Introduction:Idiopathic phrenic nerve palsy is a rare cause of exertional dyspnea. We present a case of a patient presenting with worsening dyspnea of an unknown etiology found to be related to bilateral phrenic nerve palsy.Discussion:Forty-two-year-old man presented to our emergency department with exertional dyspnea, orthopnea, and a left lower lobe consolidation treated initially as bronchitis by his primary physician as an outpatient, then subsequently as pneumonia at another institution, with no improvement in symptomatology. After admission to our hospital, CT chest demonstrated only supradiaphragmatic atelectatic changes. Echocardiography was normal. Bronchoscopy was contemplated however the patient could not lie flat. A fluoroscopic sniff test demonstrated diaphragmatic dysfunction and pulmonary function tests revealed restrictive pulmonary disease with evidence of neuromuscular etiology. Nerve conduction studies confirmed bilateral phrenic neuropathy. He was referred to a specialized neuromuscular disease center where subsequent workup did not demonstrate any specific etiology. A sleep study confirmed sleep disordered breathing suggestive of diaphragmatic paralysis and he was discharged on bi-level positive pressure ventilation.Conclusion:This is a unique case of exertional dyspnea and orthopnea from diaphragmatic paresis caused by bilateral phrenic nerve palsy where the initial workup for pulmonary and cardiovascular etiologies was essentially unremarkable. Shortness of breath and orthopnea caused by phrenic neuropathy is a rare condition, yet has a variety of etiologies. Our case suggests a template to the diagnostic approach, management, and follow up of bilateral phrenic nerve palsy.

“De Novo” Hypercapnic Respiratory Failure Unmasking Neuromuscular Disorders: Experiences From a Tertiary Care Center and Review of Literature

“…Functional respiratory recovery has been documented in nearly 43% of patients after 1 year in patients with unilateral or bilateral isolated diaphragm paralysis. 17,25 Hence, the extent of involvement as assessed by phrenic nerve conductions and diaphragm thickening need not necessarily indicate a poor prognosis as observed in our study. The role of respiratory rehabilitation and gradual titration of the newer advanced NIV/BIPAP machines needs special mention in improving the prognosis of these patients.…”

“…Antecedent infections including pneumonia and herpes zoster could cause phrenic nerve palsies secondary to a postinfectious inflammatory process. 17 The spectrum of adult-onset chronic hypercapnic respiratory failure is expanding and includes diseases such as late-onset central hypoventilation syndrome due to mutations in PHOX2B gene. 18…”

“…Antecedent infections including pneumonia and herpes zoster could cause phrenic nerve palsies secondary to a postinfectious inflammatory process. 17 The spectrum of adult-onset chronic hypercapnic respiratory failure is expanding and includes diseases such as late-onset central hypoventilation syndrome due to mutations in PHOX2B gene. 18 during triage was noted in 4 patients, and this could be attributed to further suppression of central respiratory drive and could potentially precipitate respiratory arrests.…”

Peripheral nervous system and neuromuscular disorders in the emergency department: A review

“…Isolated phrenic neuropathy with diaphragmatic weakness has been associated with GBS, neuralgic amyotrophy, pneumonia, herpes zoster, drugs (e.g., amiodarone and chemotherapy), and malignancy and in the postoperative setting. 66,67 Patients with unilateral phrenic palsies are usually asymptomatic and often diagnosed due to an incidental radiological finding of an elevated hemidiaphragm.…”