An odd case of orthopnea

SESSION TITLE: Pulmonary Manifestations of Systemic Disease Case Report Posters 4 SESSION TYPE: Case Report Posters PRESENTED ON: 10/09/2023 12:00 pm - 12:45 pm INTRODUCTION: Orthopnea is a particular form of dyspnea that occurs while lying flat. Heart failure and pulmonary disease are common diagnoses, but other causes exist. CASE PRESENTATION: A 50-year-old male patient developed insidious orthopnea associated with left shoulder and neck pain over 3 months with no associated symptoms. History included hypertension, class 1 obesity and tobacco use. On examination, marked dyspnea was observed when asking the patient to lay down; breath sounds were present and symmetrical, and the neurological examination was normal. The chest radiograph showed elevated right hemidiaphragm, but no active cardio-pulmonary process. Echocardiogram was normal. On pulmonary function testing (PFT), forced vital capacity (FVC) was 3,06 L (61% of expected) while sitting and 1.11 L (22%) while supine, a 63% positional change. Both maximal inspiratory and expiratory pressures were reduced, –41 cm of water (33%) and 135 cm of water (57%) respectively. The sniff test showed a faint symmetrical decreased respiratory diaphragmatic motion. Electromyogram (EMG) was consistent with neuromuscular weakness involving both brachial plexus and diaphragmatic muscle (Parsonage and Turner syndrome). DISCUSSION: Compared to unilateral, bilateral diaphragmatic paralysis may be more challenging to diagnose. Patients often have more marked orthopnea and more frequent complications such as atelectasis and hypercapnic respiratory failure (1). Yet, chest radiograph and sniff test may be misleading because the upward movement of the ribs by the accessory inspiratory muscles may result in false downward movement of the diaphragm. On PFT, reduced maximal respiratory pressures, especially the maximal inspiratory pressure is suggestive. A supine FVC should be ordered in case of doubt (2). EMG can be useful to distinguish neuropathies from myopathies. Parsonage and Turner syndrome is rare, usually with unilateral diaphragmatic paralysis but bilateral cases have been reported (3). CONCLUSIONS: Diaphragmatic paralysis can present with orthopnea that requires specific testing. Bilateral paralysis can be a diagnostic challenge. REFERENCE #1: Skatrud J, Iber C, McHugh W, Rasmussen H, Nichols D. Determinants of hypoventilation during wakefulness and sleep in diaphragmatic paralysis. Am Rev Respir Dis 1980; 121(3):587-593 REFERENCE #2: Ward NS, Hill NS. Pulmonary function testing in neuromuscular disease. Clin Chest Med 2001; 22(4):769-781 REFERENCE #3: Odell JA, Kennelly K, Stauffer J. Phrenic nerve palsy and Parsonage-Turner syndrome. Ann Thorac Surg 2011; 92(1):349-351 DISCLOSURES: No relevant relationships by Philippe Bauer, value=Grant/Research Support Removed 02/19/2023 by Philippe Bauer, source=Web Response No relevant relationships by Philippe Bauer, value=Grant/Research Support Removed 02/19/2023 by Philippe Bauer, source=Web Response No relevant relationships by Mohamad El Labban No relevant relationships by Syed Khan