[Acquired hemophilia A treated with rituximab. Report of one case]. / Hemofilia adquirida tratada con anti CD20, un anticuerpo anti linfocito B.

We report a 54-year-old male presenting with a history or recurrent nose bleeds and ecchymoses. The coagulation study showed a prolonged partial thromboplastin time, a factor VIII of 8% and a high inhibitor titer (193 Bethesda units). A diagnosis of acquired hemophilia A was reached. The patient was initially treated with cyclophosphamide for seven months without response. Therefore rituximab in doses of 375 mglm²/week for four weeks was started. After starting treatment, the patient had a hematoma in the psoas muscle with a concomitant factor VIII of less than 5%, that was treated with local measures. Thereafter, a progressive reduction in inhibitor titers was observed, until its disappearance at five months of treatment. Factor VIII levels normalized and the patient has not experienced abnormal bleeding episodes. The patient remains in remission after 67 months of follow up. Rituximab, a chimeric monoclonal antibody against the protein CD 20 is an effective treatment in acquired hemophilia A.

Hemofilia adquirida tratada con anti CD20, un anticuerpo anti linfocito B / Acquired hemophilia a treated with rituximab. Report of one case

We report a 54-year-old male presenting with a history or recurrent nose bleeds and ecchymoses. The coagulation study showed a prolongedpartial thromboplastin time, a factor VIII of 8 percent and a high inhibitor titer (193 Bethesda units). A diagnosis of acquired hemophilia A was reached. The patient was initially treated with cyclophosphamide for seven months without response. Therefore rituximab in doses of 375 mglm²Iweek for four weeks was started. After starting treatment, the patient had a hematoma in the psoas muscle with a concomitantfactor VIII ofless than 5 percent, thatwas treated with local measures. Thereafter, aprogressive reduction in inhibitor titers was observed, until its disappearance atfive months of treatment. Factor VIII levéis normalized and the patient has not experienced abnormal bleeding episodes. The patient remains in remission after 67 months offollow up. Rituximab, a chimeric monoclonal antibody against theprotein CD 20 is an effective treatment in acquired hemophilia A.

Dirección de las mutaciones factor V Leiden y protrombina G20210A en pacientes con trombosis venosa / Direction of the mutations factor V Leiden and Prothrombin G20210A in patients with venous thrombosis

El tromboembolismo venoso es una condición patológica de origen multifactorial, incluyendo causas adquiridas o genéticas. De estas últimas, las mutaciones puntuales factor V Leiden y Protrombina G20210A representan etiologías más frecuentes de trombosis hereditaria. Para el diagnóstico de estos efectos genéticos en pacientes con trombosis venosa, se realizan las técnicas de biología molecular de reacción en cadena de la polimerasa y polimorfismo del tamaño de los fragmentos de restricción. Desde febrero del 2001hasta diciembre de 2005 se realizaron 565 exámenes para la detección del factor V Leiden, encontrándose un 6,19 por ciento de prevalencia (35 pacientes). Esta cifra contrasta con algunos estudios y esta en concordancia con otros. En el mismo periodo se realizaron 557 exámenes para la detección de Protrombina G20210A, encontrándose un 6,1 por ciento de prevalencia (34 pacientes), valor que es muy similar a la mayoría de las series clínicas descritas.

Venous thromboembolism is a pathological condition of multifactorial origin, including acquired and genetic causes. The point mutation factor V Leiden and Prothrombin G2021OA are the most frequent etiologies of hereditary thrombosis. To diagnose these genetic defects in patients with venous thrombosis, the molecular biological technique of polymerase chain reaction – restriction fragment length polymorphism (PCR-RFLP) is used. In this study, 565 exams for the detection of factor V Leiden were carried out from February, 2001 through December, 2005, finding a prevalence of 6.19 percent (35 patients). This rate contradicts some studies and agrees with others. In the same period, 557 exams for the detection of prothrombin G2021OA were performed, finding a prevalence of 6.1 percent (34 patients), a very similar value to the prevalence reported in the majority of the published clinical series.

[Frequency and characteristics of aspirin resistance in Chilean cardiovascular patients]. / Frecuencia y características de la resistencia a aspirina en pacientes cardiovasculares chilenos.

BACKGROUND: Studies performed in Anglo-Saxon countries show that 5% of patients are resistant to the antiplatelet effects of aspirin. AIM: To assess the prevalence of aspirin resistance in a sample of Chilean cardiovascular patients and its association with clinical and laboratory characteristics. PATIENTS AND METHODS: Ninety nine patients (30 women, 63+/-10 years) treated for stable cardiovascular diseases with aspirin 100-325 mg/day were studied. Clinical and basic coagulation variables were assessed. Platelet aggregation was studied with platelet rich plasma using three different agonists in an optical aggregometer. Aspirin resistance was defined as an aggregation 20% with arachidonic acid and an aggregation 70% with ADP or collagen. RESULTS: Eleven patients (11.11%, 95% CI= 4.95-17.27%) complied with both criteria and were classified as aspirin resistant. Current smoking was more common in aspirin resistant patients (63.6 vs 29.6%, p=0.039). CONCLUSIONS: Aspirin resistance was found in a significant proportion of cardiovascular patients and was more common among current smokers.

Proteína S libre en embarazadas normales: comparación entre dos métodos / Free protein S (PS) in normal pregnancy: A comparison between two analytical methods

Background: Pregnancy is a physiological hypercoagulable state with an increased incidence of thromboembolic phenomena. There is an increase in the concentrations of most clotting factors, a decrease in concentration of some of the natural anticoagulants and reduced fibrinolytic activity. Changes in PS levels have also been reported. Aim: To establish referral range values of functional PS and free PS antigen, during the second (2nd T) and third trimester (3rd T) of normal gestation. Patients and methods: Forty one normal pregnant women were included in our study, 20 during the 2nd T (22-24 weeks) and 21 during the 3rd T (29-38 weeks). Functional PS was measured by a clot based test and free PS antigen by ELISA. Results: Free PS Antigen was 65.8±18.3% during the 2nd T and 62.3±16.5% during the 3rd T. The figures for normal controls were 106±6.5%. Functional PS was 43.8±13.3 and 25.9±14.6% during the 2nd T and 3rd T, respectively. The figures for normal controls were 97±24% (p <0.001 compared with pregnant women). Free PS antigen did not change from the 2nd to the 3rd T (p=NS), however functional PS fell significantly from the 2nd to the 3rd T (p <0.001) and was significantly lower than free PS antigen in both trimesters (p <0.001). Conclusions: Pregnancy is associated to a decrease in PS. This abnormality is more pronounced for functional PS than free PS antigen and functional PS falls progressively during pregnancy. These assays should not be used to screen for PS deficiency during pregnancy because they could lead to a misdiagnosis.

Frecuencia y características de la resistencia a aspirina en pacientes cardiovasculares chilenos / Frequency and characteristics of aspirin resistance in Chilean cardiovascular patients

Background: Studies performed in Anglo-Saxon countries show that 5 percent of patients are resistant to the antiplatelet effects of aspirin. Aim: To assess the prevalence of aspirin resistance in a sample of Chilean cardiovascular patients and its association with clinical and laboratory characteristics. Patients and Methods: Ninety nine patients (30 women, 63n10 years) treated for stable cardiovascular diseases with aspirin 100-325 mg/day were studied. Clinical and basic coagulation variables were assessed. Platelet aggregation was studied with platelet rich plasma using three different agonists in an optical aggregometer. Aspirin resistance was defined as an aggregation >20 percent with arachidonic acid and an aggregation >70 percent with ADP or collagen. Results: Eleven patients (11.11 percent, 95 percent CI= 4.95-17.27 percent) complied with both criteria and were classified as aspirin resistant. Current smoking was more common in aspirin resistant patients (63.6 vs 29.6 percent, p=0.039). Conclusions: Aspirin resistance was found in a significant proportion of cardiovascular patients and was more common among current smokers.

Determinación de factores trombofílicos en pacientes con trombosis venosas retinianas / Markers of thrombophilia in patients with retinal vein thrombosis

Background: Thrombophilia is an alteration of hemostasis that increases the risk to venous or arterial thrombosis. This condition may be the underlying cause of retinal vein thrombosis. Aim: To study the presence of thrombophilia in patients with retinal vein thrombosis. Patients and methods: Prospective study of 55 patients aged 22 to 86 years, with retinal vein thrombosis (central or branch). Antithrombin III, coagulant protein C, functional protein S, resistance to activated C protein, homocysteine, prothrombin G20210A gene, lupus anticoagulant and anticardiolipin antibodies were measured in all. Results: Seventeen patients had thrombophilic markers (antiphospholipid syndrome in seven, hyperhomocysteinemia in six and resistance to protein C in three). Of these 17 patients, 53percent had high blood pressure, 35percent an abnormal serum lipid profile and 23percent a personal history of thrombosis. The thrombosis was central in 12 (ischemic in four) and of a branch in five (ischemic in two). Conclusions: Thrombophilic markers must be assessed in patients with retinal vein thrombosis.

Intoxicación por rodendicida - superwarfarina: descripción de un caso clínico / Poisoning by rodenticide - superwarfarin: description of a clinical case

Los rodendicidas de uso doméstico están fácilmente disponibles en el comercio y, corresponden en general a superwarfarinas, cuyo mecanismo de acción es semejantea los anticoagulantes de uso clínico, pero difiere en una vida media más prolongada (meses) y una potencia cien veces mayor.Presentamos el caso clínico de una intoxicación con fines suicidas de Rodilon® (difethialone) 10 cajas de 50 g. La paciente ingresa con un tiempo de protrombina(TP) de 6 por ciento con un INR de 12.4, requiriendo administración de vitamina K1 durante varios meses. Las manifestaciones clínicas fueron leves (gingivorragia y petequias) al ingreso.En caso de no contar con el antecedente de ingesta, la intoxicación debe sospecharse en toda hipoprotrombinemia adquirida, sin antecedentes familiares de diátesis hemorrágica y, con función hepática normal.