TOPIC: Signs and Symptoms of Chest Diseases
      TYPE: Medical Student/Resident Case Reports
      INTRODUCTION: Orthopnea is defined as shortness of breath or difficulty breathing in recumbent position. It occurs as a result of decreased lung compliance and vital capacity, causing pulmonary congestion due to the redistribution of body fluids. Orthopnea is most commonly associated with heart failure, but it can also be caused by massive ascites, diaphragm paralysis, pleural effusion, morbid obesity, pneumonia, or chronic obstructive pulmonary disease.
      CASE PRESENTATION: A 77 year old male presented to our institution with two months history of orthopnea, but denied paroxysmal nocturnal dyspnea, dyspnea on exertion, and leg swelling. Patient also did not have any history of trauma or surgery to the neck or chest. On presentation, patient was saturating well on room air and physical exam was only significant for decreased breath sounds in right lung base. Chest radiograph showed marked elevation of right hemidiaphragm with bowel loops interposed between diaphragm and liver as normal anatomic variant, which was better demonstrated on computed tomography of the chest without any underlying consolidation, effusion, or lesion. Transthoracic echocardiography showed ejection fraction of 40-45%, grade one diastolic dysfunction, and global hypokinesis. Despite borderline ejection fraction, according to both Framingham and Boston criteria, diagnosis of heart failure was unlikely for this patient.
      DISCUSSION: Although orthopnea is most commonly associated with heart failure, positive predictive value for orthopnea in diagnosis of heart failure is only 14.5% with likelihood ratio of only 2.2. It is imperative to be mindful of other differential diagnosis for early recognition and proper management. Unilateral diaphragmatic paralysis is one of the uncommon causes of orthopnea that occurs when a hemidiaphragm is unable to contract to allow proper inspiration. Some causes for diaphragm dysfunction include trauma, compression of phrenic nerve, neuropathic demyelinating disorders, or inflammatory etiology. Diaphragm plication has been reported to be effective and safe procedure for symptomatic unilateral diaphragm paralysis.
      CONCLUSIONS: Elevated hemidiaphragm is often asymptomatic and an incidental finding on chest radiograph; however, in severe cases, it can lead to respiratory failure and death.
      REFERENCE #1: Ekundayo OJ, Howard VJ, Safford MM, et al. Value of orthopnea, paroxysmal nocturnal dyspnea, and medications in prospective population studies of incident heart failure. Am J Cardiol. 2009;104(2):259-264. doi:10.1016/j.amjcard.2009.03.025
      REFERENCE #2: McGee, Steven. Chapter 19 - Respiratory Rate and Abnormal Breathing Patterns, Editor(s): Steven McGee, Evidence-Based Physical Diagnosis (Fourth Edition), Elsevier, 2018, Pages 145-156.e4, ISBN 9780323392761
      REFERENCE #3: Wang CS, FitzGerald JM, Schulzer M, Mak E, Ayas NT. Does this dyspneic patient in the emergency department have congestive heart failure? JAMA. 2005 Oct 19;294(15):1944-56. Review. PubMed PMID: 16234501.
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