Acute superior mesenteric vein thrombosis in the setting of cytomegalovirus mononucleosis: a case report and review of the literature.

Cytomegalovirus is a viral genus of the overarching family Herpesviridae, and is of particular importance because of its relevance to human disease. This association is predominantly due to human cytomegalovirus, a well-studied pathogen. In addition to the mononucleosis syndrome that can occur during acute cytomegalovirus viraemia, this virion has been recurrently implicated as a provoking factor for thromboembolic disease in the published scientific literature. As physicians increasingly forgo extensive laboratory investigation in the setting of clinical hypercoagulability, it has also become evident that in some circumstances whether or not a particular investigation alters clinical management is not necessarily the only important question. Viraemia as a provoking factor for thrombosis stands as such an example. The aim of this Grand Round is to further explore the role of cytomegalovirus as it pertains to thromboembolic disease, especially in the present era of viral-associated thromboembolism.

Is donating blood for the faint of heart? a systematic review of predictors of syncope in whole blood donors.

BACKGROUND: Adverse events during donation negatively impact the likelihood of subsequent donation. Syncope is a possible complication of blood donation in healthy individuals. This systematic review aims to identify risk factors for syncope in healthy blood donors. STUDY DESIGN AND METHODS: Medline, Embase, Cochrane, CINAHL, Web of Science, Transfusion Evidence Library, and PubMed libraries up to November 2016 were searched. Inclusion criteria were observational and interventional trials, case series including more than 10 participants, randomized controlled trials, and clinical trials. Papers required data pertaining to syncopal events separate from presyncope for inclusion. Incomplete text or non-English language versions were excluded. Papers were evaluated using the CHARMS 2014 checklist. RESULTS: From 3316 papers, 1297 unique citations were identified, and 11 were selected for data extraction. Sex, estimated blood volume, age, donor status, blood pressure, heart rate, weight, previous reaction, caffeine, sleep, and donation site were identified as risk factors for syncope during blood donation. CONCLUSION: Possible risk factors for syncope in healthy blood donors have been identified that could allow for improved screening prior to donation and potential reduction in donor attrition due to negative experiences.

Cold agglutinin disease complicating management of aortic dissection.

BACKGROUND: Cold agglutinin disease is characterized by acrocyanosis, hemolytic anemia, and occasionally, frank hemoglobinuria. Although cold agglutinins are commonly detected, they are rarely clinically significant due to subphysiologic temperatures at which agglutination occurs. Cardiovascular surgical procedures requiring hypothermia present a unique challenge for these patients, requiring modification of the conduct of cardiopulmonary bypass and cardioplegia. CASE REPORT: Herein we report a case of a patient with a prior history of symptomatic cold agglutinin disease and type A aortic dissection, presenting with dilation of his known diseased ascending aorta, requiring semi-urgent repair. The patient underwent plasma exchange on two successive days preceding surgery to reduce the cold agglutinin titre. A modified Bentall procedure and replacement of ascending aorta and hemiarch under deep hypothermic circulatory arrest was performed without complication. CONCLUSIONS: This case demonstrates the efficacy of employing plasma exchange in preparation for cardiac surgery with deep hypothermic circulatory arrest in a patient with clinically significant cold agglutinin disease. Plasma exchange alone may be sufficient in preparing patients with cold agglutinin disease for procedures requiring significant hypothermia when the delayed onset of action of alternative therapies is not acceptable. Choice of replacement fluid is critical in ensuring maintenance of coagulation proteins perioperatively and minimizing complement activation.

Cytopenias and clonal expansion of gamma/delta T-cells in a patient with anaplasmosis: a potential diagnostic pitfall.

Human granulocytic anaplasmosis is a rare, tick-borne infectious disease caused by Anaplasma phagocytophilum. Herein, we report a rare case of human granulocytic anaplasmosis associated with cytopenias and clonal expansion of gamma/delta T-cells in the bone marrow. A 77-year old man presented multiple times to the emergency department complaining of muscle weakness. Complete blood count detected cytopenias and peripheral blood smear showed pseudo Pelger-Huet neutrophils. These findings prompted bone marrow evaluation with ancillary studies including flow cytometry, karyotyping and T-cell rearrangement studies. Careful examination of peripheral blood smear revealed very rare neutrophils with intracytoplasmic inclusions, suggestive of ehrlichiosis/anaplasmosis. Bone marrow evaluation showed dyserythropoiesis, dysmegakaryopoiesis and prominence of hemophagocytic histiocytes. Furthermore, an increased number of T-cells was seen in the bone marrow and flow cytometry showed excess of gamma/delta T-cells, while T-cell rearrangement studies detected a T-cell clone. Serologic evaluation confirmed the diagnosis of anaplasmosis. This case nicely illustrates hematologic sequelae of infection with Anaplasma and potential diagnostic pitfalls, such as myelodysplastic syndrome and T-cell lymphoproliferative disorder. To our knowledge, this is the first reported case of clonal expansion of gamma/delta T-cells associated with anaplasmosis. Pathologists should be careful and vigilant when screening peripheral blood smears, as they are often the first to raise the suspicion of anaplasmosis.

Guidance on platelet transfusion for patients with hypoproliferative thrombocytopenia.

Patients with hypoproliferative thrombocytopenia are at an increased risk for hemorrhage and alloimmunization to platelets. Updated guidance for optimizing platelet transfusion therapy is needed as data from recent pivotal trials have the potential to change practice. This guideline, developed by a large international panel using a systematic search strategy and standardized methods to develop recommendations, incorporates recent trials not available when previous guidelines were developed. We found that prophylactic platelet transfusion for platelet counts less than or equal to 10 × 10(9)/L is the optimal approach to decrease the risk of hemorrhage for patients requiring chemotherapy or undergoing allogeneic or autologous transplantation. A low dose of platelets (1.41 × 10(11)/m2) is hemostatically as effective as higher dose of platelets but requires more frequent platelet transfusions suggesting that low-dose platelets may be used in hospitalized patients. For outpatients, a median dose (2.4 × 10(11)/m2) may be more cost-effective to prevent clinic visits only to receive a transfusion. In terms of platelet products, whole blood-derived platelet concentrates can be used interchangeably with apheresis platelets, and ABO-compatible platelet should be given to improve platelet increments and decrease the rate of refractoriness to platelet transfusion. For RhD-negative female children or women of child-bearing potential who have received RhD-positive platelets, Rh immunoglobulin should probably be given to prevent immunization to the RhD antigen. Providing platelet support for the alloimmunized refractory patients with ABO-matched and HLA-selected or crossmatched products is of some benefit, yet the degree of benefit needs to be assessed in the era of leukoreduction.

High affinity hemoglobin and Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SN) region of the midbrain. Oxidative damage in this region has been shown to play an important role in the pathogenesis of this disease. Human neurons have been discovered to contain hemoglobin, with an increased concentration seen in the neurons of the SN. High affinity hemoglobin is a clinical entity resulting from mutations that create a functional increase in the binding of hemoglobin to oxygen and an inability to efficiently unload it to tissues. This can result in a number of metabolic compensatory changes, including an elevation in circulating hemoglobin and an increase in the molecule 2,3-diphosphoglycerate (2,3-DPG). Population based studies have revealed that patients with PD have elevated hemoglobin as well as 2,3-DPG levels. Based on these observations, we hypothesize that the oxidative damage seen in PD is related to an underlying high affinity hemoglobin subtype.

Neutralization positive but apparent false-positive hepatitis B surface antigen in a blood donor following influenza vaccination.

We report a case of transient, confirmed positive hepatitis B surface antigen (HBsAg) in a 25 year old long term Canadian Blood Services (CBS) donor, who reported receiving 2011-2012 seasonal trivalent (A/H1N1, A/H3N2, Influenza B) inactivated influenza vaccine two days before donation. To our knowledge, this report is the first published case implicating influenza vaccine as a possible factor in false-positive HBsAg test results. Seasonal incidence of repeat-reactive HBsAg among CBS donors suggests a potential contributory role of influenza vaccine or community acquired infection. We speculate that influenza vaccine may rarely be associated with sporadic, transient, false-positive HBsAg results.

Thrice weekly warfarin administration in haemodialysis patients.

BACKGROUND: Medication adherence in haemodialysis patients is often challenging due to a high pill burden, complex and dynamic medication regimens and limited patient self-interest in care. The purpose of this study was to investigate the time within target INR and safety profile of thrice weekly warfarin administration in haemodialysis patients with a clinical indication for anticoagulation and documented nonadherence to medications. METHODS: Thirty-seven patients from two haemodialysis units in Winnipeg, Manitoba, Canada, were recruited, and 17 patients were treated with thrice weekly warfarin and compared to 20 patients treated with daily warfarin therapy. The patients were followed for 1 year with weekly international normalized ratio (INR), dosage and adverse events recorded. The primary outcome was percentage of time with INR in target and sub (<1.5)- and supra (>4)-therapeutic INR. Adverse events were recorded in the two groups. RESULTS: The thrice weekly group had a higher burden of comorbidity (Charlson comorbidity index of 6.35 +/- 1.77 versus 4.55 +/- 1.64, P = 0.003) compared to the daily dosage group. In the thrice weekly dosage group, time within target INR was higher (56.9 versus 49.3%, P = 0.008), and time with supra-therapeutic INR > 4 lower (2.7 versus 4.3%, P = 0.03). Total bleeding events (7 versus 6) and major bleeding events (3 versus 2 events) were similar between the two groups. CONCLUSION: In this pilot study, thrice weekly warfarin appears to be a safe and feasible dosing strategy in a select patient population. A randomized controlled trial of thrice weekly warfarin is warranted.