Aberrant Platelet Aggregation as Initial Presentation of Essential Thrombocythemia: Failure of Entero-Coated Aspirin to Reduce Platelet Hyperactivation.

Essential thrombocythemia (ET) is a myeloproliferative neoplasm variant characterized by excessive production of platelets. Since the most common cause of mortality and morbidity in ET patients is thrombosis, the excessive production of platelets may cause thrombotic events. However, little is known about the function of platelets in ET. We report a female patient who presented as asymptomatic, without a remarkable medical history, and ET was diagnosed after an incidental finding of moderate thrombocytosis. Notably, together with thrombocytosis, an abnormal platelet phenotype was found for the presence of a massive, rapid and spontaneous formation of aggregates and platelet hypersensitivity to subthreshold concentrations of aggregating agonists. Bone marrow histopathological examination and genetic analysis with the JAK2 (V617F) gene mutation findings confirmed the initial suspicion of ET. Although the ET patient was placed on aspirin, the persistence of the platelet hyperactivation and hyperaggregability prompted a switch in antiplatelet medication from entero-coated (EC) to plain aspirin. As result, platelet hypersensitivity to agonists and spontaneous aggregation were no longer found. Collectively, our study demonstrates that platelet function analysis could be a reliable predictor of ET and that plain aspirin should be preferred over EC aspirin to attenuate platelet hyperreactivity.

Trombocitosis esencial: comunicación de dos casos / Essential thormbocytosis: report of two cases

La trombocitosis esencial (TE) es una panmielopatía clonal de escasa frecuencia, que está incluida dentro de los síndromes mieloproliferativos crónicos. Se caracteriza por la proliferación anormal de los megacariocitos, y las manifestaciones clínicas principales son: hemorragia y/o diátesis tromboembólica, en cuyo caso se presentan fenómenos necróticos y ulcerosos. Se presentan dos pacientes de sexo masculino de 54 y 80 años, cuyas primeras manifestaciones fueron lesiones úlcero-necróticas cutáneas. Con recuentos plaquetarios mayores a 1.000.000 mm3 y la punción biopsia de médula ósea que reveló hiperplasia megacariocítica, se arriba al diagnóstico de TE.

Essential thrombocytosis (ET) is a rare, clonal panmyelopathy and one of a group of disordersknown as chronic myeloproliferative diseases.ET is associated with sustained megakaryocyte proliferation, and clinically presents hemorrhage orthrombosis with ulcerative or necrotic lesions.We report two male patients aged 54 and 80-years-old, respectively, with ulcerative and necroticlesions on the skin as the first manifestation of this disease. The platelet count was higher than1.000.000 mm3 and the bone marrow aspirate biopsy showed megakaryocytic hyperplasiadiagnostic of ET.

La leucocitosis extrema puede inducir a un diagnóstico erróneode hipoxemia severa. Descripción de un caso / Extreme leucocytosis can lead to an erroneous diagnosis of severe hypoxaemia. Description of a case

El diagnóstico y tratamiento de la insuficiencia respiratoria es parte de la prác-tica diaria del anestesiólogo, y la hipoxemia una de sus consecuencias fisiológicas y analíticas.Pacientes con una leucocitosis extrema secundaria a leucemia pueden sufrir un diagnósticoincorrecto de hipoxemia, llamada «seudohipoxemia». Esto se debe fundamentalmente al rápidoconsumo de oxígeno in vitro, y se caracteriza por una presión arterial de oxígeno (PaO2) bajaa pesar de tener una saturación de oxígeno (SpO2) normal medida por pulsioximetría. La seu-dohipoxemia se presenta en pacientes con trombocitosis o hiperleucocitosis por crisis blásticade una leucemia. Se debe sospechar en pacientes con una discrepancia entre la SpO2medidapor oximetría de pulso y la PaO2. En este contexto, el pulsioxímetro es el método más útil paraestablecer el diagnóstico y evitar actuaciones innecesarias. Presentamos el caso de un pacientecon leucemia mieloide crónica y extrema leucocitosis, intervenido de urgencia y diagnosticadode seudohipoxemia durante el período perioperatorio que conllevó un retraso en su extubación (AU)

The diagnosis and treatment of respiratory failure is a part of the anaesthesist’s dailypractice, as well as the hypoxaemia that is one of its physiological and analytical consequences.Patients with an extreme leucocytosis secondary to leukaemia can suffer an incorrect diagnosisof hypoxemia, called ‘‘pseudohypoxaemia’’. This is basically due to the rapid in vitro oxygenconsumption, and is characterized by a low partial pressure of oxygen in arterial blood (PaO2)despite a normal oxygen saturation (SpO2) measured by pulse oximetry. Pseudohypoxaemiaappears in patients with thrombocytosis or hyper-leucocytosis occurring during blastic crisis ofa leukaemia. It must be suspected in patients with a discrepancy between the SpO2measuredby oximetry and the PaO2. In this context, pulse oximetry is the most accurate way to establishthe diagnosis and to avoid unnecessary actions. We report the case of a patient with chronicmyeloid leukaemia and extreme leucocytosis requiring emergency surgery, and diagnosed with pseudohypoxaemia during the perioperative period that led to a delay in the extubation of thepatient (AU)