Atrial Myxoma Presenting as an Atypical Stroke in a Young Patient With a Recent COVID-19 Infection.

Atrial myxomas are the most common primary tumor of the heart and can occasionally present as an ischemic stroke with neurologic symptoms secondary to embolic phenomena. We present a case of a 42-year-old male with multiple cardiovascular risk factors and coronavirus disease 2019 (COVID-19) infection two months prior who presented to the emergency department with unilateral left-sided weakness and paresthesia. After being diagnosed with multifocal ischemic strokes, further evaluation utilizing a transesophageal echocardiogram (TEE) revealed a 5 × 2 cm left atrial myxoma prolapsing the mitral valve, which was the presumed cause of the patient's strokes. The myxoma was successfully removed via robotic thoracoscopy. Our case demonstrates the importance of considering atrial myxoma in the evaluation of stroke in young and middle-aged patients even in the presence of multiple cardiovascular and thrombotic risk factors.

Differential Adaptive Response of Growing Bones From Two Female Inbred Mouse Strains to Voluntary Cage-Wheel Running.

The phenotypic response of bones differing in morphological, compositional, and mechanical traits to an increase in loading during growth is not well understood. We tested whether bones of two inbred mouse strains that assemble differing sets of traits to achieve mechanical homeostasis at adulthood would show divergent responses to voluntary cage-wheel running. Female A/J and C57BL6/J (B6) 4-week-old mice were provided unrestricted access to a standard cage-wheel for 4 weeks. A/J mice have narrow and highly mineralized femora and B6 mice have wide and less mineralized femora. Both strains averaged 2 to 9.5 km of running per day, with the average-distance run between strains not significantly different (p = 0.133). Exercised A/J femora showed an anabolic response to exercise with the diaphyses showing a 2.8% greater total area (Tt.Ar, p = 0.06) and 4.7% greater cortical area (Ct.Ar, p = 0.012) compared to controls. In contrast, exercised B6 femora showed a 6.2% (p < 0.001) decrease in Tt.Ar (p < 0.001) and a 6.7% decrease in Ct.Ar (p = 0.133) compared to controls, with the femora showing significant marrow infilling (p = 0.002). These divergent morphological responses to exercise, which did not depend on the daily distance run, translated to a 7.9% (p = 0.001) higher maximum load (ML) for exercised A/J femora but no change in ML for exercised B6 femora compared to controls. A consistent response was observed for the humeri but not the vertebral bodies. This differential outcome to exercise has not been previously observed in isolated loading or forced treadmill running regimes. Our findings suggest there are critical factors involved in the metabolic response to exercise during growth that require further consideration to understand how genotype, exercise, bone morphology, and whole-bone strength interact during growth. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.