ABSTRACT
TOPIC: Pulmonary Physiology TYPE: Fellow Case Reports INTRODUCTION: Respiratory muscle weakness is known to occur in neurodegenerative disorders, including Huntington's disease (HD), and causes 25% of deaths in this population. Though diaphragmatic dystonia has been described in some neurodegenerative diseases, it has not been in HD. In general, little published data exists on overall respiratory function and diaphragmatic movement in HD. CASE PRESENTATION: We describe a 58-year-old male with HD, presenting with progressive dyspnea over 1 year and an accompanying choking sensation upon awakening. Cardiac evaluation with echocardiogram and dobutamine stress test revealed only left ventricular hypertrophy. Family history includes HD in his mother, diagnosed at autopsy age 72;an older brother with HD onset at 53 that died at 62;a maternal aunt with onset in her 50s that died in her 70s. His maternal grandmother and 2 other family members also had involuntary movements believed to be chorea. Most died from respiratory complications. Physical exam showed adequate air entry bilaterally, with clear breath sounds and decreased chest wall expansion. No abdominal paradox or diaphragm dysfunction was appreciated in supine or seated position. On walking oximetry, he became tachypneic and dyspneic after 2 minutes of walking, prompting him to stop. His saturation on room air did not drop below 96%. Heart rate increased to 110 beats per minute. Laboratory panel revealed hemoglobin 13.8 g/dl. A venous blood gas revealed pH 7.38 and pCO2 of 49.A dynamic digital chest radiography (DDR) was performed during two tidal breaths and a forced inspiratory and expiratory maneuver. This revealed decreased bilateral lung inflation. Diaphragmatic contours were elevated bilaterally with a mildly reduced excursion. During the breathing cycle multiple independent diaphragmatic contractions were appreciated on forced inspiration and exhalation resulting in paradoxical motion and dyssynchrony. There was exaggerated use of accessory muscles in the shoulder girdle as a compensatory mechanism. Spasms in the upper airway were also noted throughout the test. Because of covid restrictions, the patient is awaiting pulmonary function tests. DISCUSSION: DDR uniquely provides the opportunity to interrogate respiratory physiology and identify diaphragmatic abnormalities, such as coordination impairments and dyssynchrony compared to static chest radiography;with lower levels of radiation as used in video fluoroscopy. As previously described1, we suggest that the understanding of dyspnea in patients with neurologic disease is enhanced using DDR. CONCLUSIONS: We report the first case of diaphragmatic chorea in a patient with HD using DDR. Future studies are needed to better understand this newly recognized phenomenon of diaphragmatic discoordination and its association with shortness of breath. REFERENCE #1: O'Sullivan M, Singh A, Prime D, Moore J, Zink S. A Whole New Chest X-Ray. ATS 2019 ePoster Viewing Site. Published May 2019. Accessed April 28, 2021. https://cslide-us.ctimeetingtech.com/ats2019_eposter/attendee/eposter/poster/6529 DISCLOSURES: No relevant relationships by Norma Braun, source=Web Response No relevant relationships by Jose Concepcion, source=Web Response No relevant relationships by Natasha Garg, source=Web Response No relevant relationships by Mary O Sullivan, source=Web Response No relevant relationships by Valeria Santibanez, source=Web Response