The Hematologist

March-April 2017, Volume 14, Issue 2

When More (Oxygen) Is Not Better

Jason Gotlib, MD, MS Professor of Medicine
Stanford University School of Medicine, Stanford, CA
Evan T. Hall, MD, Mphil Fellow in Hematology/Oncology
Stanford University School of Medicine, Stanford, CA
Scott Wendroth, MD Hematopathology Fellow
Stanford University School of Medicine, Stanford, CA

Published on: March 01, 2017

A 58-year-old Asian woman with a history of inclusion body myositis on high-dose corticosteroids and methotrexate was noted to be hypoxic (oxygen saturation 86% by pulse oximetry) in an outpatient clinic. She had recently been started on dapsone for PCP prophylaxis. Her vital signs were otherwise stable. She reported fatigue, but no cough, fevers, or other symptom concerning for infection. Further laboratory work-up revealed a white blood cell count of 18 × 109/L, hemoglobin of 6.9 g/dL (MCV 106 fL), and platelet count of 182 × 109/L. Reticulocytes made up 8 percent of her red blood cells. Her hemoglobin was 12 g/dL two weeks prior. She reported no history of bleeding. Despite an increasing concentration of supplemental oxygen (up to 15 L/min by facemask), she remained with a saturation of 87 percent. Chest x-ray was clear, and CT pulmonary embolism (PE) protocol did not reveal a PE. A peripheral blood smear was obtained and is shown in the Figure below:

IC Hall 3/3/17



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