Platelet size for distinguishing between inherited thrombocytopenias and immune thrombocytopenia: a multicentric, real life study.

The most frequent forms of inherited thrombocytopenia (IT) are characterized by platelet size abnormalities and it has been suggested that this parameter is useful for their differentiation from immune thrombocytopenia (ITP). Recently, a monocentric study identified cut-off values for mean platelet volume (MPV) and mean platelet diameter (MPD) with good diagnostic accuracy in this respect. To validate these cut-off values in a different and larger case series of patients, we enrolled 130 subjects with ITP and 113 with IT in six different centres. The platelet count and MPV was each measured by the instrument routinely used in each institution. In some centres, platelet count was also measured by optical microscopy. MPD was evaluated centrally by image analysis of peripheral blood films. The previously identified cut-off value for MPV had 91% specificity in distinguishing ITP from inherited macrothrombocytopenias (mono and biallelic Bernard-Soulier, MYH9-related disease), while its sensitivity was greatly variable depending on the instrument used. With an appropriate instrument, specificity was 83%. The diagnostic accuracy of MPD was lower than that obtained with MPV. We concluded that MPV is a useful parameter for differentiating ITP from IT provided that it is measured by appropriate cell counters.

Idiopathic pulmonary hemosiderosis: a rare cause of iron-deficiency anemia in childhood.

Idiopathic pulmonary hemosiderosis is a chronic, rare disorder confined to the lung, which is commonly characterized by the triad of recurrent hemoptysis, diffuse parenchyma infiltrates on chest radiography, and iron-deficiency anemia. Diagnosis may be difficult and the clinical course may be widely variable. Here, we describe an 8-year-old boy whose isolated symptom on presentation was iron-deficiency anemia. Presence of hemoptysis and bilateral alveolar infiltrates on chest x-ray led to the diagnosis of pulmonary hemosiderosis, subsequently confirmed by the finding of hemosiderin-laden macrophages by bronchoalveolar lavage. The patient was started on prednisolone 2 mg/kg/d and no further bleeding episodes were noted after the onset of therapy.

Association of Immune Thrombocytopenia and Inflammatory Bowel Disease in Children.

BACKGROUND: The association between inflammatory bowel disease (IBD) and immune thrombocytopenia (ITP) is still uncertain. In this multicenter retrospective study, the coexistence of both diseases was investigated in children diagnosed from 1 January 2000 to 31 December 2019. METHODS: Clinical characteristics of both IBD and ITP, onset of disorders, and patient's response to treatment were collected through a structured form sent to 55 Italian pediatric referring centers for hematological disorders. RESULT: Centers responded to the survey and reported the coexistence of IBD and ITP in 14 children. The first diagnosis was ITP in 57.1% and IBD in 35.7% of patients: it was simultaneous in 7.1%. IBD was classified as ulcerative colitis (57.1%), Crohn disease (35.7%), and unclassified (7.1%). No therapy for IBD other than steroids had any effect on ITP course. Colectomy resulted in recovery from ITP in 1 of the 2 patients surgically treated. ITP was always mild but turned to be chronic in half of patients. CONCLUSIONS: In all patients, ITP was mild without any evident impact on IBD severity, but the incidence of chronic ITP seems to be higher than what is usually observed in the pediatric age group. Colectomy had unpredictable effects on ITP.

von Willebrand disease type 2B must be always considered in the differential diagnosis of genetic thrombocytopenias with giant platelets.

Type 2B von Willebrand's disease (VWD) is an inherited bleeding disorder characterized by spontaneous binding of large von Willebrand factor (VWF) multimers to platelets in vivo. This phenomenon induces the clearance of both large multimers and platelets, usually resulting in thrombocytopenia with slightly increased platelet size. We describe a newborn with a VWD type 2B due to the heterozygous missense mutation V1316M who presented the atypical feature of giant platelets in peripheral blood. Based on this observation and literature review, we suggest that the diagnosis of VWD 2B should be always considered in patients with chronic thrombocytopenia and giant platelets.

Tc-99m tetrofosmin tomography after nitrate administration in patients with ischemic left ventricular dysfunction: relation to metabolic imaging by PET.

BACKGROUND: In patients with ischemic left ventricular (LV) dysfunction, myocardial perfusion imaging after nitrate administration may improve the identification of dysfunctional but viable myocardium. This study was designed to assess the relationship between tetrofosmin uptake after nitrate administration and metabolic activity as assessed by positron emission tomography (PET) in patients with ischemic LV dysfunction. METHODS AND RESULTS: Thirty-six patients with chronic myocardial infarction and LV dysfunction (ejection fraction, 35% +/- 6%) underwent resting technetium 99m tetrofosmin single photon emission computed tomography (SPECT) imaging under control conditions (baseline) and after sublingual administration of 10 mg isosorbide dinitrate. Within 1 week, all patients underwent metabolic PET imaging with fluorine 18-fluorodeoxyglucose. Tetrofosmin uptake and metabolic activity were measured in 13 segments/patient. Regional LV function was assessed in corresponding segments by echocardiography. On baseline tetrofosmin imaging, 53 (40%) of the 131 akinetic or dyskinetic segments had reduced (<55% of peak activity) tracer uptake. Of these segments, 14 (26%) showed enhanced tetrofosmin uptake after nitrate administration (>/=10% vs baseline) and the remaining 38 (74%) did not change. The sensitivity and specificity of baseline tetrofosmin SPECT for detecting preserved metabolic activity were 69% and 86%, respectively. After nitrate administration, the sensitivity was higher (81%, P <.05 vs baseline) whereas the specificity was not different (86%, P = not significant). Concordance between tetrofosmin SPECT and PET in differentiating viable and necrotic myocardium was observed in 94 (72%) of the 131 akinetic or dyskinetic segments at baseline (kappa = 0.35) and in 108 segments (82%) after nitrate administration (kappa = 0.53). CONCLUSIONS: After nitrate administration, tetrofosmin uptake in dysfunctional segments correlated with metabolic activity as assessed by fluorodeoxyglucose PET imaging better than baseline. Thus tetrofosmin SPECT after nitrate administration may improve the identification of ischemic but still viable myocardium in patients with chronic ischemic LV dysfunction.