Physicians' information needs routinely arise during their practice. Several studies have demonstrated that a useful way to understand the nature of the needs is to examine questions posed by physicians during the course of medical care. This paper presents an analysis of clinical questions collected when physicians were engaged in reviewing clinical cases. The main objective of the study was to investigate characteristics of the physicians' information needs to provide insight into the development of a conceptual guidance approach in information retrieval. The analysis focused on categories, search contexts, and patterns of the questions with respect to the scenarios. The results of the study showed that physicians' information needs exhibited distinct characteristics according to the scenarios, and that their needs could be expressed with a relatively small number of question patterns. These observations supported our approach of using patterns of information needs in facilitating digital information access.