Risk of invasive Haemophilus influenzae type b (Hib) disease in adults with secondary immunodeficiency in the post-Hib vaccine era.

Prior to the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, invasive Hib disease affected almost exclusively children. According to some recent studies, in the postvaccine era, adults, the elderly, and immunocompromised persons can be affected more often than children. As the production of type-specific anti-capsular polysaccharide antibodies is the major defense mechanism against Hib, individuals with defects in humoral immune responses have high susceptibility to infections caused by Hib. We hypothesized that nonvaccinated adults with chronic conditions causing immunosuppression may lack protective antibody to Hib. We assessed serum anti-Hib IgG levels and bactericidal activity in 59 patients with chronic renal failure, 30 patients with type 2 diabetes mellitus, 28 patients with chronic obstructive pulmonary disease (COPD), and 20 patients with multiple myeloma compared to 32 healthy controls of similar age. Considering antibody at >0.15 µg/ml as the protective correlate in unvaccinated individuals, we detected subprotective Hib antibody levels in 29% of chronic renal failure, 20% of diabetes, 14% of COPD, and 55% of myeloma patients compared to 3% of healthy controls. Additionally, 70% of myeloma and 58% of chronic renal failure patients did not have detectable serum bactericidal activity against Hib. Among individuals with severe diseases causing secondary immunodeficiency, patients with multiple myeloma and chronic renal failure are at an increased risk of invasive Hib disease. Considering that Hib continues to circulate in the population, this study provides a rationale for the immunization of some adult patients with secondary immunodeficiency with the pediatric Hib vaccine to achieve protective immunity.

Factitious biochemical measurements resulting from hematologic conditions.

Factitious laboratory results often lead to unnecessary testing or treatment. This brief review of factitious biochemical results due to preexisting hematologic conditions focuses on the mechanisms underlying the factitious results and suggests ways to prevent them. An observant pathologist identifies these errors, intervenes in a timely fashion, investigates the sources of error diligently, and institutes measures to prevent their recurrence.

A survey of recipient client physician satisfaction with teleoncology services originating from thunder bay regional health sciences centre.

The objective of this work was to investigate end user satisfaction and perceived efficacy on the part of client physicians for teleoncology services in Northwestern Ontario. A survey of 98 referring physicians from 17 remote communities in Northwestern Ontario was undertaken primarily to determine overall client physician satisfaction with the teleoncology process. The survey also investigated perceived problems and explored potential solutions. Overall client physician satisfaction was high for the majority of response fields. However, more than 50% of surveyed physicians felt that some aspects of the teleoncology process could be improved with an emphasis on more timely communication of interview results, continuity of care, and improving patients comfort level with the technologies involved. The success of this service is evidenced by its exponential growth since the original introduction in 2001. Ninety-eight percent of referring physicians would continue to use the teleoncology service process.

Artifacts that may be present on a blood film.

Many artifacts or pseudoartifacts may be noted during the examination of a blood film. Artifactual results also may be generated by automated hematology analyzers, which in turn may be investigated by blood film examination. Some artifacts are misdiagnosed, and this in turn leads to inappropriate investigations or treatment. An awareness of the spectrum of spurious or artifactual results may help to prevent such an unfortunate occurrence.

The anti-phospholipid syndrome.

Preview Antiphospholipid antibodies may be found in a variety of clinical situations, including in the absence of systemic disease. Certainly, for cost-effective healthcare, physicians should not spend resources evaluating otherwise healthy people. However, when features of the antiphospholipid syndrome (APS) are also present, serious venous or arterial thrombosis or recurrent spontaneous abortion may ensue. The authors present a practical overview of the antibodies and how to uncover and manage APS.

Oral anticoagulant therapy.

Preview The overall prescription of oral anticoagulants has steadily increased as important randomized clinical trials have clarified various indications for therapy. However, a number of practical matters related to initiation, monitoring, dose adjustment, and management are less frequently addressed. Moreover, this information can be difficult to find, even in major textbooks. Rather than providing a comprehensive review of oral anticoagulants, this article emphasizes various practical aspects of therapy.

A systematic approach to macrocytosis.

Preview Macrocytosis has causes other than folate or vitamin B12 deficiency, including chronic alcohol ingestion and various forms of drug therapy. In this article, Dr Brigden presents clinical cases that illustrate five different causes of macrocytosis, with comments on each case to facilitate the overall approach to diagnosis and management.

When bleeding complicates oral anticoagulant therapy.

Preview The risk-benefit ratio of oral anticoagulant therapy is of special concern in the 1990s, because potential uses of these agents are expanding rapidly. A careful review of all aspects of therapy with patients new to anticoagulants may improve compliance and lessen the incidence of bleeding, the major complication. Dr Brigden provides case reports to illustrate risk factors for bleeding, approaches to determining the source, and management of elevated prothrombin time.