A 57-year-old hypertensive, obese woman presented with several weeks of a febrile flu-like illness, facial and extremity flushing, and laboratory findings of polycythemia. A workup revealed no evidence of polycythemia rubra vera or a secondary cause of her polycythemia (her erythropoietin level was normal, she had no splenomegaly, and a test for JAK2 v617F mutation was negative). Over the next two weeks, her fever subsided, and her hematological profile returned to normal, pre-illness levels. We conclude that this patient had Gaisbock's syndrome, a relative polycythemia that occurs when there is clinically evident contraction of the intravascular fluid space (plasma volume). KeywordsPolycythemia, Hypertension, Plasma volume, Packed cell volume, Venesection, Erythromelalgia resolved over a two-week period as she recovered from her illness. Studies for primary and secondary causes of polycythemia were negative, supporting the diagnosis of Gaisbock's syndrome. Case ReportThe patient, a 57-year-old Caucasian woman, was seen because of a two-week history of fever and a flu-like illness. Her illness began with mild upper airway symptoms (coryza, sore throat), accompanied by myalgias, arthralgias, malaise, fatigue, and anorexia followed by an intermittent non-productive cough and exacerbation of her migraine headaches. She also noted the occurrence of flushing of her face and swelling and flushing of the soles of her feet. Her past medical history was notable for hypertension, a multinodular thyroid, and mild IgM deficiency. She was taking hydrochlorothiazide and triamterene for her hypertension, but was on no other medications. She was a non-smoker, had no history of sleep apnea, and kept herself well hydrated during the illness. Her husband had experienced a flu-like illness 2-3 weeks earlier, and she had recently been immunized to influenza, but the vaccine did not cover 40% of the prevalent strains.Physical examination revealed a temperature of 102 °F, a blood pressure of 138/100, a regular pulse of 74 beats/minute, a respiratory rate of 14 breaths/minute, and a BMI of 41. Facial flushing, which increased in the recumbent position, was present, and the soles of both feet had increased warmth, diaphoresis, and erythema characteristic of erythromelalgia (Figure 1). Her oropharynx was mildly injected without exudates. She had no adenopathy, and the examination of her heart, lungs, and abdomen was unremarkable. Her skin turgor was normal. CASE STUDY

Background Blastomyces fungi, endemic to the Ohio and Mississippi River Valleys, cause pneumonia and disseminated disease in both immunocompetent and immunocompromised patients. Prolonged antifungal therapy is commonly complicated by hepatic toxicity, QT prolongation, and drug interactions. Isavuconazonium sulfate is dosed once daily, does not prolong the QT interval, and has fewer drug interactions, but there is a paucity of data for its use in blastomycosis. Methods This case series of blastomycosis treated with isavuconazonium sulfate at the University of Wisconsin Hospital and Clinics from 2015 to December 2019 focuses on long term outcomes. Inclusion criteria were adults, that received at least one day of isavuconazole. Exclusion criteria was no blastomycosis diagnosis. Results Of 14 cases, median age was 53 years, 6/14 were female, 11/14 White, 2/14 Black, 1/14 Hmong, 6/14 had a solid organ transplant (4 renal, 1 heart, 1 bilateral lung), 1/14 on a TNF-alpha inhibitor (infliximab). Most cases, 9/14 had moderate severity illness requiring inpatient care, 2/14 required ICU level care, and 3/14 were outpatient. Most cases, 11/14, were initially treated with Liposomal Amphotericin B (LAMB) for a median duration of 14 days, 9/14 cases received itraconazole, 8/14 voriconazole, 1/14 posaconazole. Isavuconazonium sulfate was started after adverse drug effects with other azoles in 10/14 cases, prolonged QT interval in 3/14, drug interactions in 2/14, subtherapeutic azole levels in 2/14. Isavuconazonium sulfate was well tolerated and used for median duration of 255 (average 68% total treatment course). 3/14 cases had adverse reactions to isavuconazonium sulfate: nausea, rash, elevated liver enzymes. There was only one death during therapy from a fatal hemorrhagic stroke, and 2/14 cases were still on therapy at end of data collection. 11/14 were cured after treatment course. Conclusion This is the largest case series treating Blastomycosis with isavuconazonium sulfate, and it adds to the evidence that isavuconazonium sulfate can be safely used to treat pulmonary and disseminated blastomycosis. Prospective data is needed to compare isavuconazonium sulfate to other antifungals for the treatment of Blastomycosis. Disclosures All Authors: No reported disclosures