Biomedical subjects

Jean B Brière

Publications and source records attributed to Jean B Brière.

3 recordsLinked to original sources

PubMed2007

Essential thrombocythemia.

Essential thrombocythemia (ET) is an acquired myeloproliferative disorder (MPD) characterized by a sustained elevation of platelet number with a tendency for thrombosis and hemorrhage. The prevalence in the general population is approximately 30/100,000. The median age at diagnosis is 65 to 70 years, but the disease may occur at any age. The female to male ratio is about 2:1. The clinical picture is dominated by a predisposition to vascular occlusive events (involving the cerebrovascular, coronary and peripheral circulation) and hemorrhages. Some patients with ET are asymptomatic, others may experience vasomotor (headaches, visual disturbances, lightheadedness, atypical chest pain, distal paresthesias, erythromelalgia), thrombotic, or hemorrhagic disturbances. Arterial and venous thromboses, as well as platelet-mediated transient occlusions of the microcirculation and bleeding, represent the main risks for ET patients. Thromboses of large arteries represent a major cause of mortality associated with ET or can induce severe neurological, cardiac or peripheral artery manifestations. Acute leukemia or myelodysplasia represent only rare and frequently later-onset events. The molecular pathogenesis of ET, which leads to the overproduction of mature blood cells, is similar to that found in other clonal MPDs such as chronic myeloid leukemia, polycythemia vera and myelofibrosis with myeloid metaplasia of the spleen. Polycythemia vera, myelofibrosis with myeloid metaplasia of the spleen and ET are generally associated under the common denomination of Philadelphia (Ph)-negative MPDs. Despite the recent identification of the JAK2 V617F mutation in a subset of patients with Ph-negative MPDs, the detailed pathogenetic mechanism is still a matter of discussion. Therapeutic interventions in ET are limited to decisions concerning the introduction of anti-aggregation therapy and/or starting platelet cytoreduction. The therapeutic value of hydroxycarbamide and aspirin in high risk patients has been supported by controlled studies. Avoiding thromboreduction or opting for anagrelide to postpone the long-term side effects of hydrocarbamide in young or low risk patients represent alternative options. Life expectancy is almost normal and similar to that of a healthy population matched by age and sex.

Adult↗

PubMed2006

Budd-Chiari syndrome and portal vein thrombosis associated with myeloproliferative disorders: diagnosis and management.

The improvement observed in the prognosis of Budd-Chiari syndrome (BCS) since 1985 may be related to a better identification of underlying prothrombotic states. In a recent investigation of the currently identified prothrombotic disorders, one or several prothrombotic disorders were evidenced in 72% of patients with portal vein thrombosis (PVT) and 87% of patients with hepatic vein thrombosis. According to the different criteria used for their diagnosis, myeloproliferative disorders (MPDs) were reported in 25 to 65% of patients with splanchnic vein thrombosis (STV). In a single-center retrospective study of 128 patients with STV, clusters of abnormal megakaryocytes in bone marrow biopsy combined with endogenous erythrocyte colony formation were used as reference standards for a diagnosis of MPD. These two criteria allowed the diagnosis of MPDs at risk of aggravation in 25% (26 of 103) of patients with STV (41% in BCS; 23% in PVT). After a mean follow-up of 6.09 +/- 6.6 years, hematologic progression was confirmed in 23% of patients with the two criteria both positive, whereas neither progression nor features suggestive of MPD were observed in patients with the same concordant negative criteria. The combination of marked splenomegaly and platelet count > 200 x 10 (9)/L that was never observed in patients without MPD, constitutes a simple index for the suspicion of an underlying MPD, but the absence of an obvious splenic enlargement and normal or decreased platelet numbers may even be observed in patients with MPD-associated STV. In the absence of reliable indicators of the exact expansion of the myeloproliferative clone, the therapeutic management of STV-associated MPD is difficult to standardize. Owing to the suspected incidence on the prognosis of BCS of an associated MPD, the present watchful-waiting attitude proposed in MPD without obvious hematologic expression may be challenged.

Budd-Chiari Syndrome↗

PubMed2005

Relevance of the criteria commonly used to diagnose myeloproliferative disorder in patients with splanchnic vein thrombosis.

Myeloproliferative disorders (MPD) are reported in 25-65% of patients with splanchnic vein thrombosis (SVT). Diagnostic criteria for MPD have not been fully established in this context. Using clusters of abnormal megakaryocytes in bone marrow (BM) biopsy as a reference standard for Philadelphia negative MPD, we assessed the relevance of other criteria currently recommended for the diagnosis of MPD in SVT (128 consecutive SVT patients). First, usual criteria were compared with BM results: endogenous erythroid colony formation (EEC) was strongly correlated with BM results; splenomegaly, blood cell count, total red cell volume, erythropoietin level and cytogenetic were much less accurate. Then, patients were assigned to three groups according to the combination of BM and EEC findings (group I: both present; group II: both absent; group III: other patients); clinical presentation and outcome were compared in each group. At a mean follow-up of 6.09 +/- 6.6 years, progression to a severe form of MPD occurred in 7 of 31 group I patients (23%), in 1 of 34 group III patients (3%) and 0 of 63 group II patients. The combination of marked splenomegaly and platelet count >200 x 10(9)/l was restricted to groups I and III. In conclusion, in patients with SVT, BM findings and EEC allowed the diagnosis of MPD at risk of aggravation. Marked splenomegaly in association with platelet counts >200 x 10(9)/l constitute a simple index with high specificity but low sensitivity.

Bone Marrow Cells↗