Jason C. Ford

Carrier Screening for Thalassemia and Hemoglobinopathies in Canada

OBJECTIVE To provide recommendations to physicians, midwives, genetic counsellors, and clinical laboratory scientists involved in pre-conceptional or prenatal care regarding carrier screening for thalassemia and hemoglobinopathies (e.g., sickle cell anemia and other qualitative hemoglobin disorders). OUTCOMES To determine the populations to be screened and the appropriate tests to offer to minimize practice variations across Canada. EVIDENCE The Medline database was searched for relevant articles published between 1986 and 2007 on carrier screening for thalassemia and hemoglobinopathies. Key textbooks were also reviewed. Recommendations were quantified using the Evaluation of Evidence guidelines developed by the Canadian Task Force on Preventive Health Care. VALUES The evidence collected from the Medline search was reviewed by the Prenatal Diagnosis Committee of the Canadian College of Medical Geneticists (CCMG) and the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC). BENEFITS, HARMS, AND COSTS Screening of individuals at increased risk of being carriers for thalassemia and hemoglobinopathies can identify couples with a 25% risk of having a pregnancy with a significant genetic disorder for which prenatal diagnosis is possible. Ideally, screening should be done pre-conceptionally. However, for a significant proportion of patients, the screening will occur during the pregnancy, and the time constraint for obtaining screening results may result in psychological distress. This guideline does not include a cost analysis. RECOMMENDATIONS 1. Carrier screening for thalassemia and hemoglobinopathies should be offered to a woman if she and/or her partner are identified as belonging to an ethnic population whose members are at higher risk of being carriers. Ideally, this screening should be done pre-conceptionally or as early as possible in the pregnancy. (II-2A) 2. Screening should consist of a complete blood count, as well as hemoglobin electrophoresis or hemoglobin high performance liquid chromatography. This investigation should include quantitation of HbA2 and HbF. In addition, if there is microcytosis(mean cellular volume < 80 fL) and/or hypochromia (mean cellular hemoglobin < 27 pg) in the presence of a normal hemoglobin electrophoresis or high performance liquid chromatography the patient should be investigated with a brilliant cresyl blue stained blood smear to identify H bodies. A serum ferritin (to exclude iron deficiency anemia) should be performed simultaneously. (III-A) 3. If a womans initial screening is abnormal (e.g., showing microcytosis or hypochromia with or without an elevated HbA2, or a variant Hb on electrophoresis or high performance liquid chromatography) then screening of the partner should be performed. This would include a complete blood count as well as hemoglobin electrophoresis or HPLC, HbA2 and HbF quantitation,and H body staining. (III-A) 4. If both partners are found to be carriers of thalassemia or an Hb variant, or of a combination of thalassemia and a hemoglobin variant, they should be referred for genetic counselling. Ideally,this should be prior to conception, or as early as possible in the pregnancy. Additional molecular studies may be required to clarify the carrier status of the parents and thus the risk to the fetus. (II-3A) 5. Prenatal diagnosis should be offered to the pregnant woman/couple at risk for having a fetus affected with a clinically significant thalassemia or hemoglobinopathy. Prenatal diagnosis should be performed with the patients informed consent. If prenatal diagnosis is declined, testing of the child should be done to allow early diagnosis and referral to a pediatric hematology centre, if indicated. (II-3A) 6. Prenatal diagnosis by DNA analysis can be performed using cells obtained by chorionic villus sampling or amniocentesis. Alternatively for those who decline invasive testing and are at risk of hemoglobin Barts hydrops fetalis (four-gene deletion alpha-thalassemia), serial detailed fetal ultrasound for assessment of the fetal cardiothoracic ratio (normal < 0.5) should be done in a centre that has experience conducting these assessments for early identification of an affected fetus. If an abnormality is detected, a referral to a tertiary care centre is recommended for further assessment and counselling. Confirmatory studies by DNA analysis of amniocytes should be done if a termination of pregnancy is being considered. (II-3A) 7. The finding of hydrops fetalis on ultrasound in the second or third trimester in women with an ethnic background that has an increased risk of alpha-thalassemia should prompt immediate investigation of the pregnant patient and her partner to determine their carrier status for alpha-thalassemia. (III-A) VALIDATION: This guideline has been prepared by the Prenatal Diagnosis Committee of the Canadian College of Medical Geneticists (CCMG) and the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and approved by the Board of Directors of the CCMG and the Executive and Council of the SOGC.

A new paradigm for teaching Histology laboratories in Canada's first distributed medical school

To address the critical problem of inadequate physician supply in rural British Columbia, The University of British Columbia (UBC) launched an innovative, expanded and distributed medical program in 2004–2005. Medical students engage in a common curriculum at three geographically distinct sites across B.C.: in Vancouver, Prince George and Victoria. The distribution of the core Histology course required a thorough revision of our instructional methodology. We here report our progress and address the question “How does one successfully distribute Histology teaching to remote sites while maintaining the highest of educational standards?” The experience at UBC points to three specific challenges in developing a distributed Histology curriculum: (i) ensuring equitable student access to high quality histological images, (ii) designing and implementing a reliable, state‐of‐the‐art technological infrastructure that allows for real‐time teaching and interactivity across geographically separate sites and (iii) ensuring continued student access to faculty content expertise. High quality images—available through any internet connection—are provided within a new virtual slide box library of 300 light microscopic and 190 electron microscopic images. Our technological needs are met through a robust and reliable videoconference system that allows for live, simultaneous communication of audio/visual materials across the three sites. This system also ensures student access to faculty content expertise during all didactic teaching sessions. Student examination results and surveys demonstrate that the distribution of our Histology curriculum has been successful. Anat Sci Ed 1:95–101, 2008.

If not, why not? Reasons why Canadian postgraduate trainees chose—or did not choose—to become pathologists

Pathology has been frequently identified in the literature as an unpopular choice for medical students. For many years, there have been predictions that this unpopularity would lead to inadequate pathologist numbers, which would in turn contribute to poor quality patient care. In Canada, the predicted crisis has become a reality: after a high-profile failure of laboratory quality, a public inquiry reported that poor pathology recruitment was partially responsible and recommended that medical schools take steps to make pathology more attractive to medical students. There are several published studies into pathology recruitment, but none has asked nonpathology residents why they did not choose pathology. This study uses qualitative techniques to investigate why pathology residents chose to specialize in pathology and why clinical residents rejected a pathology career. Pathology residents across Canada were surveyed, as were clinical (nonpathology) residents in every residency training program at the University of British Columbia in Vancouver, Canada. Pathology residents overwhelmingly cited various attractive features of pathology practice, including its academic nature, the opportunity to explore basic pathogenesis, and its interesting and varied daily work. Most clinical residents rejected pathology because they preferred direct patient contact; however, a sizable minority blamed insufficient or inadequate medical school experiences in pathology. Clinical residents also cited several misconceptions and stereotypes about pathology, including misunderstandings about the role of pathologists and the nature of pathology practice. The reasons why clinical residents rejected pathology careers may provide guidance in improving pathology recruitment of medical students.

The role of platelet counts in the assessment of inpatient women with preeclampsia.

OBJECTIVE Platelet count has been proposed as a screening test for generalized coagulopathy in women with preeclampsia. We performed this study to determine the relationship between platelet counts and the risk of abnormal coagulation and adverse maternal outcomes in women with preeclampsia. METHODS We used data from women in the PIERS (Pre-eclampsia Integrated Estimate of RiSk) database. Abnormal coagulation was defined as either an international normalized ratio result greater than and/or a serum fibrinogen level less than the BC Womens Hospital laboratorys pregnancy-specific normal range. The relationship between platelet counts and adverse maternal outcomes was explored using a logistic regression analysis. The sensitivity, specificity, positive predictive value, and negative predictive value of platelet counts in identifying abnormal coagulation or adverse maternal outcomes were calculated. RESULTS Abnormal coagulation occurred in 105 of 1405 eligible women (7.5%). The odds of having abnormal coagulation were increased for women with platelet counts < 50 × 10(9)/L (OR 7.78; 95% CI 3.36 to 18.03) and between 50 and 99 × 10(9)/L (OR 2.69; 95% CI 1.44 to 5.01) compared with women who had platelet counts above 150 × 10(9)/L. Platelet counts < 100 × 10(9)/L were associated with significantly increased odds of adverse maternal outcomes, most specifically blood transfusion. A platelet count of < 100 × 10(9)/L had good specificity in identifying abnormal coagulation and adverse maternal outcomes (92% [95% CI 91% to 94%] and 92% [95% CI 91% to 94%], respectively), but poor sensitivity (22% [95% CI 15% to 31%] and 16% [95% CI 11% to 23%], respectively). CONCLUSION A platelet count < 100 × 10(9)/L is associated with an increased risk of abnormal coagulation and maternal adverse outcomes in women with preeclampsia. However, the platelet count should not be used in isolation to guide care because of its poor sensitivity. Whether or not a platelet count is normal should not be used to determine whether further coagulation tests are needed.

Transfusion medicine problems and solutions for the pediatric hematologist/oncologist†

Blood component transfusion is an integral part of the care of children with oncologic and hematologic conditions. The complexity of transfusion medicine may however lead to challenges for pediatric hematologists/oncologists. In this review, three commonly encountered areas of transfusion medicine are explored. The approach to the investigation and management of suspected platelet refractoriness is reviewed. The unique transfusion related challenges encountered by children undergoing stem cell transplantation are also discussed. Finally, issues arising out of the care of children with hemoglobinopathies are explored, with an emphasis on the incidence of allo‐ and autoimmunization. Pediatr Blood Cancer 2012; 58: 1106–1111.

Multiple intracranial tumors in Philadelphia chromosome positive acute lymphoblastic leukemia: Successful treatment following aggressive supportive care, early cranial radiation, high dose chemotherapy and imatinib

We report the first case of multiple intracranial tumors (“chloromas”) at diagnosis of Philadelphia chromosome positive acute lymphoblastic leukemia. The patient presented comatose with signs of cerebral herniation. Initial management of raised intracranial pressure and hyperleukocytosis followed by emergent whole brain radiation therapy reversed the life‐threatening neurological signs. High‐dose chemotherapy combined with daily imatinib mesylate induced a rapid and sustained bone marrow remission. Ongoing rehabilitation resulted in a near complete neurological recovery within 6 months of diagnosis. This outcome justifies aggressive early management of increased intracranial pressure and hyperleukocytosis in future similar presentations. Pediatr Blood Cancer 2008;51:135–137.

Red blood cell morphology reporting: how much is a waste of time?

Red blood cell morphology (RBC-M) reporting is a routine requirement for hospital laboratories when reporting complete blood counts. However, there is little evidence that RBC-M reporting is useful to pediatric clinicians. We surveyed pediatric hematology specialists and nonspecialists at the BC Childrens Hospital (Vancouver, Canada), to evaluate the perceived clinical utility of this reporting. Although a large majority of pediatric clinicians refer to RBC-M reports in their clinical practice, less than half consider these reports to be clinically useful. Hematology specialists were more likely than nonspecialists to identify individual RBC-M descriptions as clinically useful. Some RBC-M descriptions, such as anisocytosis, were considered not useful by specialists and by nonspecialists. A large proportion of nonspecialist respondents noted that they did not know the clinical significance of some of the RBC-M terms. Educational initiatives to inform nonspecialists about the clinical significance of some RBC-M descriptions should be considered. A few RBC-M descriptions are not clinically useful to either specialists or nonspecialists, and these could be omitted from RBC-M reports as a step toward improved hematology laboratory reporting.

Exflagellating Plasmodium vivax in Peripheral Blood

3-year-old boy originally from Pakistan developed a high fever (temperature, 408C) accompanied by rigors and chills. The boy had moved to Canada with his family 1 year before presentation. He had previously been well. There was no history of recent travel, no other family members were ill, and immunizations were up to date. The findings on physical exam were noncontributory. A vial of EDTA-anticoagulated blood was submitted to the laboratory approximately 50 minutes after the blood was drawn from the boy in the emergency department. A peripheral smear and complete blood cell count were immediately generated. The count revealed mild anemia and moderate thrombocytopenia: hemoglobin, 8.2 g/dL (agespecific reference range, 10.7‐13.1 g/dL); hematocrit, 23.6% (reference range, 33.0%‐39.0%); platelet count, 88 3 10 3 /mL (reference range, 180‐440 3 10 3 /m L). Review of the peripheral smear identified occasional spherocytes and large platelet forms. The most significant finding was a parasitemia, with 1% to 2% of erythrocytes containing malarial ring forms and macrogametocytes. These were morphologically speciated as Plasmodium vivax. In addition, exflagellating microgametocytes were easily found

Transient appearance of GPI-deficient population in a patient with azathioprine-associated bone marrow aplasia

Dear Editor, Blood cells with glycosylphosphatidylinositol (GPI) deficiency are occasionally seen in bone marrow failure syndromes such as aplastic anemia [1–5]; they tend to persist for long time and may or may not be associated with clinical or laboratory evidence of hemolysis or other manifestations of paroxysmal nocturnal hemoglobinuria (PNH). We describe the first case of transient appearance of GPIdeficient population in a patient during azathioprineinduced marrow aplasia. The size of GPI-deficient population was large (67 %), but disappeared upon the marrow regeneration following discontinuation of the drug. An 8-year-old boy with active Crohn’s disease presented with fever and neutropenia. There was no discoloration of urine and there were no signs of clinically relevant intravascular hemolysis. His presentation followed a 3-month exposure to increasing doses of azathioprine from 12.5 to 50 mg/day with monitoring of blood counts, transaminase levels, and serum 6-thioguanine nucleotide metabolite (TGN) level. Laboratory investigations showed (Table 1) a total leukocyte count of 0.8×10/L, neutrophils of 0.43×10/L, hemoglobin of 88 g/L, platelet count of 131×10/L, and reticulocyte count of 3×10/L. The blood film did not show any blasts or features of dysplasia, megaloblastic state, or hemolysis. Serum LDH, cobalamin, and RBC folate levels were normal. Blood, urine, and stool cultures and serologic tests for hepatitis A, B, C, HIV, CMV, Parvovirus B19, and EBVwere negative. A repeat TGN level on azathioprine 50 mg daily was 327 pmole/8×10. Red blood cell level of 6-methyl mercaptopurine ribonucleotide metabolite was 807 pmole/8×10 RBC. A bone marrow aspirate and biopsy showed aplasia with cellularity of 5 %. Sugar water test was positive. Flow cytometric testing of blood for PNH at admission and a week later showed partial absence of CD55, 59, and fluorescent aerolysin (FLAER) on granulocytes, and of CD59 on RBCs. The size of the GPI-deficient clone was 67% by FLAER analysis of neutrophils (Fig. 1). The child was rehydrated and given antimicrobials and steroids. Azathioprine was discontinued. His clinical condition and blood counts recovered within 3 weeks. Repeat flow cytometric testing for PNH at 6 months showed complete disappearance of the GPIdeficient population. The patient was subsequently managed for Crohn’s disease with methotrexate, followed by infliximab and then adalimumab. He eventually underwent subtotal colectomy and end ileostomy and has remained well since then. Transient bone marrow aplasia caused by azathioprine exposure in patients with 6-thiopurine methyl transferase deficiency has been reported [6]; our patient showed partial deficiency of 6A. Z. Al Riyami : B. I. Dalal (*) Division of Laboratory Hematology, Vancouver General Hospital, Suite JPPN 1557, 910, 10th Avenue West, Vancouver BC V5Z 4E3, Canada e-mail: bakul.dalal@vch.ca

Pathology practice in Canada

In their recent editorial, Kathy Chorneyko and Jagdish Butany made several excellent points about the challenges pathologists face, including human- resource shortages and the need for provincial governments to support quality-assurance efforts.[1][1] Their final recommendation was that a national