INTRAMEDULLARY GAS: A NEW FEATURE THAT PORTENDS A POOR PROGNOSIS IN COVID-19?

ABSTRACT

SESSION TITLE Lessons Learned from Critical Care Cases SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 1225 pm - 0125 pm INTRODUCTION: Air outside the lungs, bowel, or paranasal cavities suggests critical pathology. Pneumoperitoneum is a classic example in which free abdominal air may signify hollow viscus injury and the need for emergent surgical management. Ectopic gas can also be secondary to barotrauma secondary to mechanical ventilation and concurrent lung injury;the latter being findings often observed in COVID pneumonia (1,2,3). Our case of extensive intramedullary gas in the setting of COVID pneumonia is an example of extensive dissecting air related to barotrauma, but also illustrates how it mimics dire cases of pneumoperitoneum. Therefore, it is an imaging finding that intensivists caring for COVID pneumonia patients should be aware of. CASE PRESENTATION A 52-year-old male with mild restrictive lung disease from congenital scoliosis developed COVID pneumonia and hypoxic respiratory failure requiring intubation. Clinical course was complicated by renal failure, deep venous thromboses, and radial artery occlusion. CT evaluation revealed large volume upper abdominal pre-peritoneal gas, pneumoperitoneum, soft tissue and intramedullary gas within bilateral ribs and multiple vertebral bodies. Despite reassuring abdominal exams, the patient deteriorated. The patient was placed on comfort care and expired. DISCUSSION: Intramedullary gas refers to the presence of air within the cortical or trabecular bone, bone marrow, or medullary cavity. It is an exceedingly rare imaging finding which was first described in ischemic vertebral collapse and osteomyelitis (4,5). Differential diagnosis includes infection, trauma, degenerative and iatrogenic causes (5,6). Embryologically, fascial layers of the thorax and periosteal coverings of the thoracic osseous structures are derived from the mesoderm, thus creating a continuum between the lungs, surrounding soft tissues, peritoneum, and surrounding osseous structures, and therefore allowing gas to travel between the lung and intramedullary space (7). As cases of COVID pneumonia with ARDS increase, we are becoming aware of the increasing incidence of ectopic air, and the poor prognosis and increased mortality that results (1). Therefore, the finding of intramedullary gas is an important prognostic indicator that the clinician should be aware of. CONCLUSIONS: Several recent studies demonstrate increased mortality in COVID patients who develop ectopic gas as a result of barotrauma and/or acute lung injury (1,2,3). As such the clinician should be aware of these findings, which include pneumomediastinum, subcutaneous emphysema, pneumoperitoneum, pre-peritoneal air, and intramedullary gas for early recognition. Reference #1 1. Lemmers DHL, Abu Hilal M, Bnà C, Prezioso C, Cavallo E, Nencini N, Crisci S, Fusina F, Natalini G. Pneumomediastinum and subcutaneous emphysema in COVID-19 barotrauma or lung frailty? ERJ Open Res. 2020 Nov 16;6(4)00385-2020. doi 10.1183/23120541.00385-2020. PMID 33257914;PMCID PMC7537408. Reference #2 2. Guven BB, Erturk T, Kompe Ö, Ersoy A. Serious complications in COVID-19 ARDS cases pneumothorax, pneumomediastinum, subcutaneous emphysema and haemothorax. Epidemiol Infect. 2021 Jun 8;149e137. doi 10.1017/S0950268821001291. PMID 34099076;PMCID PMC8207553. Reference #3 3. Tetaj N, Garotto G, Albarello F, Mastrobattista A, Maritti M, Stazi GV, Marini MC, Caravella I, Macchione M, De Angelis G, Busso D, Di Lorenzo R, Scarcia S, Farina A, Centanni D, Vargas J, Savino M, Carucci A, Antinori A, Palmieri F, D'Offizi G, Ianniello S, Taglietti F, Campioni P, Vaia F, Nicastri E, Girardi E, Marchioni L, Icu Covid-Study Group. Incidence of Pneumothorax and Pneumomediastinum in 497 COVID-19 Patients with Moderate-Severe ARDS over a Year of the Pandemic An Observational Study in an Italian Third Level COVID-19 Hospital. J Clin Med. 2021 Nov 29;10(23)5608. doi 10.3390/jcm10235608. PMID 34884310;PMCID PMC8658701. DISCLOSURES Researc support relationship with 4D Medical Please note March 2021 Added 04/04/2022 by Anu Brixey, value=Grant/Research Support No relevant relationships by raluca mccallum