18F-fluorodeoxyglucose positron emission tomography computed tomography (18F-PET/CT) for the diagnosis of native valve infective endocarditis (NVIE): a prospective study

Background and objectives 18F-FDG PET/CT has recently been added as a major criterion in the ESC 2015 infective endocarditis (IE) guidelines. We and others have demonstrated that18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) / computed tomography (CT) was useful in patients with suspected prosthetic valve and cardiac device IE. However, the sensitivity and specificity of ESC classification is unknown in patients with native valve endocarditis (NVE) as well as the clinical impact of PET findings. Purposes 1. Primary objective: To assess the value of the new ESC criteria including 18F-FDG PET/CT in native valve infective endocarditis (NVIE). 2. Secondary objectives: – to determine the usefulness of PET/CT concerning embolic or neoplastic detection. – to describe a new PET/CT feature, i.e. the diffuse splenic uptake. Methods Between 2012 and 2017, 75 patients with suspected NVIE were prospectively included, after exclusion of patients with uninterpretable or not feasible PET/CT. Using the expert consensus of the Endocarditis Team after a 3-month follow-up as gold standard, 63 IE were confirmed and 12 were rejected. Patients follow-up was scheduled at one and three months after hospitalization. Results Significant cardiac uptake by PET/CT (major criterion) was observed in 11 among 63 patients with definite NVIE and no patients with rejected IE (sensitivity 18%, specificity 100%). Among the 63 patients with a final diagnosis of NVE, a peripheral embolism or mycotic aneurysm was observed in 20 cases (32%). Considering this, the ESC 2015 classification increased the sensitivity of Duke criteria from 64 to 70% (p<0.001) without no change on specificity (p<0.001). Twenty-four patients (38%) were diagnosed with secondary infectious sites or infectious portal of entry. A diffuse splenic uptake was observed in 39 (52%) patients, including 37 (59%) of patients with a final diagnosis of NVE (specificity 83%). Conclusion 1. The value of 18F-FDG PET/CT in NVE diagnosis is poor (18% sensitivity) 2. Usefulness of PET/CT remains high when concerning embolic or neoplastic detection. 3. Our study describes for the first time in NVE a new potential endocarditis criterion, i.e. the presence of a diffuse splenic uptake on 18F-FDG PET/CT Diffuse splenic uptake Funding Acknowledgement Type of funding source: None

STUDY OF CLINICAL FEATURES AND EPIDEMIOLOGY OF COMPLICATED VIVAX MALARIA

Severe and complicated malaria is defined by the World Health Organization Malaria Action Programme in June 19851 as the presence of one or more of the following conditions in a slide confirmed diagnosed case of malaria cerebral malaria, severe anemia, renal failure, pulmonary edema or adult respiratory distress syndrome, hypoglycemia, circulatory collapse or shock, spontaneous bleeding, repeated generalized convulsions, acidemia or acidosis, macroscopic hemoglobinuria, impairment of consciousness less marked than unarousable coma,, hyperparasitemia, jaundice, hyperpyrexia, and the presence of complicating or associated infections. However, severe anemia and thrombocytopenia that causes bleeding diatesis is produced by hemolysis, reduced cell deformity of parasitized and non-parasitized erythrocytes, increased splenic clearance, reduction of platelet survival, decreased platelet production, and increased splenic uptake of platelets. Though these changes can be produced by P. vivax and P. falciparum infection yet the complicated malaria has commonly been associated with P. falciparum infections.

Insights into determinants of spleen injury in sickle cell anemia

Spleen dysfunction is central to morbidity and mortality in children with sickle cell anemia (SCA). The initiation and determinants of spleen injury, including acute splenic sequestration (ASS) have not been established. We investigated splenic function longitudinally in a cohort of 57 infants with SCA enrolled at 3 to 6 months of age and followed up to 24 months of age and explored the respective contribution of decreased red blood cell (RBC) deformability and increased RBC adhesion on splenic injury, including ASS. Spleen function was evaluated by sequential 99mTc heated RBC spleen scintigraphy and high-throughput quantification of RBCs with Howell-Jolly bodies (HJBs). At 6 and 18 months of age, spleen filtration function was decreased in 32% and 50% of infants, respectively, whereas the median %HJB-RBCs rose significantly (from 0.3% to 0.74%). An excellent correlation was established between %HJB-RBCs and spleen scintigraphy results. RBC adhesion to laminin and endothelial cells increased with time. Adhesion to endothelial cells negatively correlated with splenic function. Irreversibly sickled cells (ISCs), used as a surrogate marker of impaired deformability, were detected at enrollment and increased significantly at 18 months. %ISCs correlated positively with %HJB-RBCs and negatively with splenic uptake, indicating a relationship between their presence in the circulation and spleen dysfunction. In the subgroup of 8 infants who subsequently experienced ASS, %ISCs at enrollment were significantly higher compared with the asymptomatic group, suggesting a major role of impaired deformability in ASS. Higher levels of %HJB-RBCs were observed after the occurrence of ASS, demonstrating its negative impact on splenic function.

Autosplenectomy in a Patient with Paroxysmal Nocturnal Hemoglobinuria (PNH)

Autosplenectomy (AS) is a known complication of diseases such as sickle cell anemia, celiac disease, and inflammatory bowel disease. We report the first known case of AS due to paroxysmal nocturnal hemoglobinuria (PNH). A 24-year-old Caucasian male had evidence of hemolytic anemia at the age of 14 and was diagnosed with PNH at the age of 16. He had recurrent episodes of sepsis due to dialysis line infections from poor hygiene, and blood cultures had been positive for multiple organisms includingStaphylococcus aureus,Enterococcus faecalis, andStreptococcus pneumoniae. The patient’s peripheral blood smears since the age of 14 years demonstrated Howell–Jolly bodies in conjunction with thrombocytopenia and hemolytic anemia, but abdominal ultrasonography reported a normal appearing spleen. The patient presented with septicemia two years after starting eculizumab, and his peripheral blood smear showed extensive Howell–Jolly bodies, Pappenheimer bodies, acanthocytes, and target cells. Splenic ultrasonography demonstrated an atrophic spleen with multifocal scarring, and absent splenic uptake of liver-spleen scintigraphy, consistent with AS. Clinicians should remain vigilant of the potential sequelae of PNH and consider the possibility of the development of AS.