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J Med Libr Assoc. 2007 Jan; 95(1): 3–8.
PMCID: PMC1773044

Utilizing case reports to build awareness of rare complications in critical care


As the second installment in the JMLA's new case study column, this issue's case considers the role of the librarian in addressing a complex clinical question that requires extracting relevant evidence when the literature is almost exclusively limited to case reports. This case study also tackles the challenge of identifying an effective strategy for organizing and presenting case report details to answer a clinical question. The commentary and discussion of results for this case were updated on September 13, 2006. We invite your commentary on this case online at <http://jmlacasestudies.blogspot.com>.


A 42-year-old male was admitted to the ICU following a motor vehicle collision (MVC). The patient currently has a diverting ileostomy, after losing most of the colon to ischemia secondary to blunt trauma to his abdomen during the MVC. The patient developed ventilator-associated pneumonia (VAP) several days after the operation to remove a significant amount of ischemic colon and construct the ileostomy; he was treated with a seven-day course of broad-spectrum antibiotics for the VAP.

After completing antibiotic therapy for the pneumonia, the patient developed diarrhea with high volume output from the ileostomy; despite consultation with the nutritionist and numerous interventions (e.g., administration of antidiarrheal agents) over the course of several days, the patient continues to have significant output from his ileostomy.

During morning rounds, one of the residents mentions that the team had sent a sample of the ileostomy output to be tested for Clostridium difficile. The team discusses the Clostridium difficile organism as one of the most common causes of diarrhea in the ICU, particularly in patients with a recent history of exposure to antibiotics. However, C. difficile typically involves the colon rather than the small intestine, and the current patient has loss of continuity between the small intestine and colon because of the ileostomy.

The attending physician notes that he has not heard of C. difficile infection involving the small intestine and asks you, as the team's evidence consultant, to explore whether the literature indicates that the small intestine can be involved in C. difficile infection and if such infection can develop despite loss of continuity with the colon (due to the presence of the ileostomy in this patient). Figure 1 includes further clinician commentary on the clinical significance of this question.

Figure 1
Clinician commentary


The initial case in this series, published in the October 2006 issue, discussed the importance of understanding the medical concepts comprising the clinical question in selecting relevant literature. Table 1 provides brief definitions of key concepts for this question, with references providing example resources for identifying such background information.

Table thumbnail
Table 1 Brief concept definitions with references to introductory-level sources of information


The selection of search terms for this question is informed by consideration of the concepts discussed in Table 1. For this search, key concepts to be represented in the search strategy include: 1) the Clostridium difficile pathogen and 2) accompanying involvement of the small bowel or presence of an ileostomy.

A search in PubMed combining these concepts might look something like: (clostridium[majr] OR clostridium infections[majr]) AND (difficile[tiab]) AND (enteritis[tiab] OR intestine, small[mh] OR ileostomy[mh] OR ileostomy[tiab]) AND humans[mh] AND eng[la].

Approximately 50 results are returned by this search. It is clear that many of the articles are not relevant to your clinical question. For example, Songer specifically addresses animals [10], while others examine related problems in infants [1112]; none of these represents your target population of adult surgical patients. Other articles focus on genetic and basic science aspects of C. difficile [1314] and can also be disregarded.

Although you have eliminated several citations based on clear cues from their title and abstract content, others will require more thorough evaluation. The Parikh citation [15] looks promising, but when you examine the text you find that it is a letter to the editor and largely summarizes two other cases published separately in the literature [1617]. A letter to the editor may occasionally point out important methodological flaws in a published piece; that does not seem to be the case for the Parikh letter, so you can safely eliminate this item.

You quickly realize that this is not a question that will be answered by clinical trials or other research methodologies: because the question does not consider an intervention or specific diagnostic strategy, a clinical trial is not suited for the topic. It also appears as though the condition is too rare to have prompted other observational work (e.g., a case control study). The available evidence for this topic is clearly limited to several relevant case reports [1626], which you select for this question. Though randomized controlled trials are often considered the “gold standard” for clinical research, case reports can be very useful in addressing a question such as this, involving a fairly rare combination of issues (C. difficile infection and involvement of the small bowel). While noting the limitations of case reports in firmly establishing associations, a number of authors emphasize the importance of such reports in summarizing issues like these that are “out of the ordinary,” providing tools for educating trainees in case-based reasoning, and prompting the generation of hypotheses for exploration in future research [2732].

In addition to the case literature, you also note an autopsy study including 100 patients, which provides C. difficile culture results from jejunal segments [33]. The positive culture results in three patients reported in this study may be worth noting, as none of the patients were diagnosed with diarrhea or other gastrointestinal symptoms before their death; this study may be useful in describing the small intestine as a possible “reservoir” for the C. difficile organism in some individuals.

During your examination of the references cited by the case reports [1626] and autopsy study [33] you have selected, you notice one additional article not included in your initial search retrieval that seems relevant to the question [34]. Retrieving the PubMed record for this article, you notice that the subject headings and the abstract do not indicate involvement of the small bowel, though one of the six cases of C. difficile infection described in the article involves a patient with an ileostomy, highlighting the importance and value of hand-searching of reference lists to complement the PubMed retrieval [3540].


Now that you have selected the cases that are most relevant to the patient case in question, you are met with the challenge of determining how to most effectively organize and summarize the information in a way that will make it quick and relatively easy for the clinical team to process and compare.

As you peruse each of the cases, you notice that they seem to fall into groups, including four cases with ileostomy [1719, 34]; one case with a history of total abdominal colectomy [16]; and eight other cases with small bowel involvement [2026]. Additionally, the autopsy study does not provide detailed cases but does include confirmed presence of C. difficile in culture of small bowel specimens in three patients [33].

The literature can also guide your selection of a format for summarizing these results. Reviews of reported cases often use tables to succinctly summarize relevant information from included cases [4143]. Though several of the articles you have selected include a tabular representation of cases reported in the literature [19, 21, 23], they provide only abbreviated description of the cases and their clinical courses; it is likely that these tables do not contain enough information to provide adequate representation of the case details, and none of these individual articles includes all the cases selected during the literature searching portion of this case study. The October case also employed a tabular format for summarizing the individual articles; your table for the current question will likely need to differ somewhat in formatting—the previous case's column labels (study design; patient population; methodology; outcome), while useful for summarizing clinical studies, do not lend themselves to the organization of case report details. For the current case, you will want to select column labels that provide for effective organization of the specifics of individual cases; Table 2 provides a suggested layout for case literature; an online version of the table is available in Word format, so that you may apply this template to summarizing the other cases selected for this question as a practice exercise. The columns selected to organize these cases include:

  • History, including details such as patient age, gender, comorbid diseases, past operations, any recent antibiotic use
  • Symptoms and signs presenting in the patient at the time clinicians began to suspect possible C. difficile infection or other disease process (e.g., abdominal pain, fever, diarrhea)
  • Lab(s), describing diagnostic tests employed to identify the source of patient signs and symptoms and key findings of the diagnostic interventions
  • Treatment details, including timing, dosage and duration of antibiotic therapy and any other interventions (e.g., surgical resection)
  • Outcome, summarizing final details of the patient's course such as duration of recovery and any other complications that developed.
Table thumbnail
Table 2 Summarizing the individual articles


As discussed in the October case, an “executive summary” of the literature on the topic will serve as an excellent introduction and synthesis of the cases you have just incorporated into the table. Considering the key points you have uncovered in your exploration of the literature, this overall summary might include:

  • Characterization of the quality and volume of literature available on this topic
  • Overview of the kinds of cases you have selected to answer this question
  • A brief description of the autopsy study [33], which didn't provide enough case details for inclusion in the tabular summarization of cases, and its connection with the current question
  • Summary of management strategies for C. difficile small bowel infection as described in the included cases, with comment regarding whether it is similar to traditional management strategies for C. difficile colitis
  • Commentary regarding the implications of small bowel C. difficile infection, i.e., morbidity and mortality risk conferred by this type of infection.

Figure 2 provides an example of how you might frame this overall state of the literature commentary.

Figure 2
Sample statement describing the overall state of the literature


The evidence you have presented to the clinical team makes them aware that active C. difficile infection is still a possibility in a patient with an ileostomy, and thus may be a cause of his diarrhea. In combination with their clinical expertise, the team uses this information to support the initiation of a course of metronidazole in this patient, which leads to the successful resolution of his diarrhea.

The evidence you extracted from the case literature has made the team aware of a clinical entity that is fairly rare and not well-known even among experienced clinicians; several members of the team comment that information presented in this way will be difficult to forget and will likely inform the care of future patients. As attention to detail is very important in the care of critically ill patients, the connections you have made between this patient case and the data available in the literature have promoted the effective treatment of his condition and resolution of symptoms that otherwise may have lead to significant complications.

Supplementary Material

Supplemental Table 2:


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