When Hearing Hoofbeats Is Actually Zebras: A Common Presentation of Uncommon Pathology

Since the beginning of the SARS CoV-2 pandemic two years ago respiratory complaints have been one of the most common presenting symptoms to the emergency departments across the United States. At this time, over 45 million Americans have tested positive for the SARS CoV-2 virus and the vast majority of the patients who present to the hospital with this infection are due to the consequences of systemic inflammation, most significantly in the lungs. We would like to share a case of a 79 year old female with known cystic lung disease (suspected Pulmonary Langerhans Cell Histiocytosis) on 4L oxygen via nasal cannula (NC) at baseline who presented to a community hospital from her nursing facility for hypoxia. Upon presentation to the hospital she was found to test positive for the SARS CoV-2 virus. In the course of her work up she received a CTA of the chest which did show mild ground glass changes consistent with a mild viral pneumonia, more significantly, the scan revealed numerous pulmonary arterio-venous malformations (AVMs) in bilateral lower lobes that were not present on previous imaging of the chest. A detailed work up of the patient was unable to be performed due to the patient declining invasive testing and wishing to pursue hospice. The patient was found to have an estimated shunt fraction >30% with a cardiac echo that confirmed an intrapulmonary shunt and an acute drop in the patient's left ventricular ejection fraction (LVEF) due to an NSTEMI 3 months prior to admission. We believe that this patient had underlying hereditary hemorrhagic telangiectasia resulting in pulmonary AVMs that were minimally symptomatic until the patient's acute drop in her LVEF which led to a drastic increase in her intrapulmonary shunt fraction.

Baby Blues: A Rare Case of Transient Pulmonary Arteriovenous Malformation During Pregnancy

Unexplained hypoxia in a pregnant patient is an alarming finding for patient and provider. The differential for hypoxia is broad, and many imaging techniques and procedures are contraindicated in pregnancy. Transient pulmonary arteriovenous malformations (AVMs) are a rare and relatively poorly studied cause of hypoxia in pregnancy. Our patient is a 27-year-old G1P0 female with a remote history of asthma who presented to clinic with slowly progressive exertional dyspnea, exertional tachycardia, and paroxysmal nocturnal dyspnea. She reported use of a home oximeter which read in the high 80s% during exertion. Prior to presentation, the patient was evaluated in the Emergency Department and noted to have an oxygen saturation of 86% on room air. A transthoracic echocardiogram, computed tomography angiography of chest, and basic laboratories including B-type natriuretic peptide, troponin, COVID-19, and hemoglobin were unremarkable. Her clinical timeline is presented in Figure 1. Further testing was obtained, including pulmonary function testing, bubble echocardiogram, nocturnal oximetry, and shunt study. Work-up revealed a 15-20% shunt, depending on calculation, and insignificant desaturations during nocturnal oximetry. Her symptoms progressed, and repeat nocturnal oximetry showed marked overnight desaturations requiring supplemental oxygen for the remainder of her pregnancy. She delivered a healthy baby girl via cesarean section without serious complication. Repeat testing in the post-partum period showed resolution of nocturnal desaturations and decreased shunt, and her exertional dyspnea and desaturations resolved spontaneously. This case illustrates the challenging diagnosis of transient pulmonary AVM in pregnancy. Case reports of this phenomenon have been published, but as in our case, no definitive diagnosis was made secondary to testing limitations in pregnancy and quick resolution of symptoms in the post-partum period. Some reports describe pre-existing pulmonary AVM becoming worse during pregnancy causing hemothorax, fetal demise and even death. While the mechanism is not known, theories include the vasodilatory effects of progesterone on vascular smooth muscle as well as other physiologic changes in pregnancy such as increased plasma volume. These AVM are thought to be like those seen in hepatopulmonary syndrome. Similar to our case, increasing positional hypoxia has been reported as the pregnancy progresses. Further research dedicated to early and accurate detection of pulmonary AVMs in pregnancy is necessary. (Figure Presented).

An uncommon case of hypoxia in a pediatric patient

INTRODUCTION: Pulmonary arteriovenous malformations (PAVM) are typically associated with hereditary hemorrhagic telangiectasia. Isolated PAVM are uncommon and usually present between the 4th-6th decades of life;they are rarely seen in children and infrequently necessitate ICU admission. DESCRIPTION: A healthy 3-year-old boy presented to his pediatrician with a 3 day history of fever and rhinorrhea. He was hypoxic (SpO2=85%), so was placed on oxygen and transferred to an outside ED where he was found to have (non-COVID) coronavirus. He was admitted for supportive care but clinically deteriorated over the next 24 hours requiring intubation, ventilatory support with 100% FiO2, and inhaled nitric oxide. Despite these interventions he remained hypoxic. Echocardiogram demonstrated a structurally normal heart. Computed tomography angiogram showed multiple large peripheral PAVM in the left lower and upper lobes and no differentiation between arterial and venous phases indicating pulmonary shunting. He was transferred to our quaternary ICU for intervention. He underwent embolization of ~70% of his PAVM (limited due to contrast load). He initially improved, but 2 days post-intervention he declined with worsening hypoxia likely secondary to pulmonary vascular remodeling following intervention and residual shunt burden within the left lung. Given his instability, as well as an oxygenation index of 34, he was cannulated for venoarterial extracorporeal membrane oxygenation (ECMO). Following cannulation, his remaining PAVM were embolized. ECMO support was subsequently weaned and he was decannulated after 4 days. His ventilator support was weaned, and he was transferred back to the referring hospital on minimal settings. He was extubated the next day and quickly weaned to room air. He was discharged after 2.5 weeks and was doing well (SpO2=95%) at his pediatrician follow-up. DISCUSSION: This is the first case of a previously healthy child requiring cannulation for ECMO due to PAVM. This case is unique among patients with PAVM due to the early presentation, likely related to an acute respiratory illness disturbing previously well-compensated ventilation-perfusion mismatch. As highlighted in this case, ECMO can be used to support patients who require interventions for PAVM and during the transition to a new physiologic state.