No abstract

Persisting heparin-induced thrombocytopenia (HIT) is characterized by ongoing thrombocytopenia more than 7 days after stopping heparin. It is part of cases referred to as autoimmune HIT (aHIT). In contrast to typical HIT cases, aHIT involves heparin-independent platelet activation mechanism highlighted by a strongly positive functional assay done without heparin. We report the first case of persisting HIT after an elective abdominal aortic aneurysm repair presenting with arterial and venous thrombosis, and describe the potential role of intravenous immunoglobulin in such patients. Keywords Case report • Heparin • Thrombocytopenia • Thrombosis • Immunoglobulin Highlights• Ongoing thrombocytopenia more than 7 days after stopping heparin and new thrombosis despite receiving treatment characterize persisting HIT. • Autoimmune HIT is characterized by a strongly positive functional assay done without heparin. • Intravenous immunoglobulin for treatment of autoimmune HIT results in improvement of thrombocytopenia and the most used dosing schedule is 1 g/kg daily for 2 doses.• Intravenous immunoglobulin should be considered as an emerging therapy for autoimmune HIT.

The Medical Council of Canada (MCC) administers a qualifying examination for the issuance of a license to practice medicine. To date, this examination does not test the clinical skills of history taking, physical examination, and communication. The MCC is implementing an objective structured clinical examination (OSCE) to test these skills in October 1992. A pilot examination was developed to test the feasibility, reliability, and validity of running a multisite, two-form, four-hour, 20-station OSCE for national licensure. In February 1991, 240 volunteer first- and second-year residents were tested at four sites. The candidates were randomly assigned to one of two forms of the test and one of two sites for two of the four sites. Generalizability analysis revealed that the variance due to form was 0.0 and that due to site was .16 compared with a total variance of 280.86. The reliabilities (inter-station) were .56 and .60 for the two forms. Station total-test score correlations, used to measure station validity, were significant for 38 of the 40 stations used (range .14-.60). The results of the OSCE correlated moderately with the MCC qualifying examination; these correlations were .32 and .35 for the two test forms. Content validity was assessed by postexamination questionnaires given to the physician examiners using a scale of 0 (low) to 10 (high). The physicians' mean ratings were: importance of the stations, 8.1 (SD, 1.8); success of the examination in testing core skills, 8.1 (SD, 1.6); and degree of challenge, 7.8 (SD, 2.1). The results indicate that a full-scale national administration of an OSCE for licensure is feasible using the model developed. Aspects of validity have been established and strategies to augment reliability have been developed.