Dyspnea as the Predominant Manifestation of Bilateral Phrenic Neuropathy

Abstract

Phrenic neuropathy associated with brachial neuritis has been well described; however, bilateral phrenic neuropathy with minimal or no involvement of the brachial plexus has not. We review the clinical features, as well as the results of radiographic studies, pulmonary function tests, and electrodiagnostic studies, of 3 patients in whom dyspnea was the presenting manifestation of bilateral phrenic neuropathy. All 3 patients had acute-onset dyspnea, which led to consideration of a pulmonary or cardiac etiology. Phrenic nerve conduction studies showed bilateral axonal degeneration of the phrenic nerves. Diaphragmatic paralysis should be considered in the differential diagnosis of acute-onset dyspnea. Dyspnea increases typically when the patient lies down, and paradoxical respiration may be present. Neck, shoulder, or upper limb pain may occur at onset. Inspiratory pressures may be reduced, but a comparison of the forced vital capacity when the patient is standing and supine is more specific for diaphragmatic weakness. Phrenic nerve conduction studies and diaphragmatic electromyography may provide evidence of bilateral involvement. Subclinical evidence of brachial plexus involvement may be present. The prognosis for patients with bilateral phrenic neuropathy may be more favorable than reported previously.

Travel to high altitude with pre-existing lung disease

“…They might not be able to raise their ventilation in response to the hypoxic conditions at high altitude and thus may develop profound arterial hypoxaemia and hypercapnia. Even if they do not have baseline hypercapnia, patients with bilateral diaphragmatic paralysis or bilateral phrenic neuropathy often have arterial hypoxaemia, particularly when supine [249,250]. As a result, they may desaturate to a significant extent at altitude, particularly during sleep.…”

Severe Acute Orthopnea: Ipilimumab-Induced Bilateral Phrenic Nerve Neuropathy

“…This case highlights the importance of physical examination in patients presenting with acute orthopnea [16,17] and the poor sensitivity of diaphragm fluoroscopy in bilateral diaphragmatic paralysis [18]. It emphasizes the emergence of diaphragmatic ultrasound as a bedside tool and spirometric lung function tests in diagnosing patients with neuromuscular disease [19,20].…”

A 54-Year-Old Man with Acute Onset Orthopnea and Sleep-Related Hypoxia

“…Long-term persistent deficit is also more consistent with BIPN. 2,3 Diaphragmatic weakness in BIPN is most often persistent, requiring lifelong noninvasive ventilatory support. However, successful relief of orthopnea and dyspnea symptoms in BIPN patients by surgical diaphragmatic plication has been reported.…”

“…14 BIPN presents as a painless paralysis of the diaphragm with relatively acute onset, and without antecedent factors such as infection or prior surgery. [2][3][4] NA is a distinct and painful brachial plexus neuropathy causing patchy, multifocal paresis and sensory loss in one or both arms, with rare involvement of the phrenic nerves. [5][6][7] A NA variant known as familial brachial plexus neuritis (hereditary neuralgic amyotrophy [HNA]) may lead to recurrent episodes of pain, numbness, and weakness in one or both upper extremities, with episodes triggered by extreme upper extremity movements or postures, infections, immunizations, or stress.…”

“…Daytime arterial blood gases showed pH 7.33, PCO 2 2) and diaphragmatic fluoroscopy confirmed bilateral diaphragmatic dysfunction and elevation. CT scan of the lung showed normal parenchyma with bilateral basal atelectasis without evidence of fibrotic changes.…”