Using cases to establish novel diagnoses: creating generic facts by making particular facts travel together

Abstract

Introduction Although some critics have questioned the epistemological value of cases, the case report continues to be exceedingly popular within medicine. It is estimated that 40,000 new case report publications are entered into the Medline database each year, with the core one hundred twenty clinical journals, on average, having 13.5 per cent of their references devoted to case reports (Rosselli and Otero 2002). In most of these journals, there are specific guidelines for what must be presented in a case report and what warrants reporting. The Lancet has a long history of publishing case reports, and began a peer-reviewed section in 1995 aimed at allowing clinicians an outlet for publication, with a particular focus on reports that have a ‘striking message’ (Bignall and Horton 1995). The New England Journal of Medicine includes brief case reports, which usually describe one to three patients or a single family, as well as case records from Massachusetts General Hospital. Many case reports begin as notifications published in the Mortality and Morbidity Weekly Report (MMWR) of the U.S. Centers for Disease Control (CDC), particularly if they are describing infectious or other types of diseases with serious public health implications. In general, the overwhelming majority of case reports depict complaints arising in specialty or subspecialty settings, and describe uncommon or even ‘unique’ clinical occurrences (McCarthy and Reilly 2000). A recent review of case studies noted that many cases report rare conditions for which trials of various types of therapies (particularly randomised or controlled trials) are not feasible due to low patient numbers or other issues, but that some cases are well received and can influence research as well as clinical practice (Albrecht et al. 2005). In contemporary medicine, cases may offer what is considered to be fairly definitive evidence in modern scientific terms, especially, for instance, with regard to unusual or unexpected occurrences such as adverse drug reactions (see, e.g., Aronson and Hauben 2006; Glasziou et al. 2007; Hauben and Aronson 2007). It is claimed that a good case study ‘begets awareness, jogs the memory and aids understanding’ (Morgan 1985, p. 353), a description that indicates the mixture of educative and epistemologic goals inherent in cases.