Cerebral microbleeds: hearing through the silence—a narrative review

Abstract

Objective: The term cerebral microbleed (CMB) refers to lesions documented as unexpected findings during computed tomography or magnetic resonance imaging examination of the brain. Initially, a CMB was thought to represent hemosiderin-laden macrophages marking an area of a tiny hemorrhage. Recently, histopathologic studies have shown that the structure of a CMB can be variable. To aid in dealing with this finding and judging its clinical significance, this review addresses important aspects of a CMB, including the definition, prevalence, and incidence in various populations, end-organ damage, associated conditions, and whether any action or treatment by the clinician might be indicated.

Methods: PubMed Medline, EMBASE, BIOSIS, Current Contents, and Derwent Drug Files databases were searched for the keywords “microbleeds-detection-damage”, “silent bleeds”, “microbleeds”, or “silent bleeds AND hemophilia” from 2011–2016. References of retrieved articles were also reviewed and included if applicable.

Results: The published data are found primarily in the imaging literature and focus on diagnostic techniques. Some publications address relationships with diverse, co-existing clinical conditions and implications for treatment, especially in stroke, intracranial hemorrhage, and antithrombotic therapy.

Conclusions: It is critical for non-radiologist clinicians (primary care, internists, neurologists, hematologists) to be aware of the potential importance of the finding of a CMB, and the fact that these lesions are not always truly silent or without important clinical consequences. As additional studies appear, clinicians may be able to “hear” more clearly through the silence of the CMB and understand potential clinical implications in patients.

Keywords:

• Internal medicine
• General practice
• Magnetic resonance imaging
• Risk factors

Transparency

Declaration of funding

This work was supported by Bayer.

Declaration of financial/other relationships

PM is an employee of Bayer. CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

The authors gratefully thank Dr Craig Kessler for his assistance with both the concept for this work and for his critical review of the manuscript, as well as Bayer for assistance with the literature search and publication support. Editorial assistance was provided by Complete Healthcare Communications, LLC (West Chester, PA) and was funded by Bayer.

Additional information

Notes on contributors

Thomas J. Humphries

TJH wrote the paper, and PM reviewed and edited all drafts. All authors approved the final version of the manuscript and agree to be accountable for all aspects of the work.

Prasad Mathew

TJH wrote the paper, and PM reviewed and edited all drafts. All authors approved the final version of the manuscript and agree to be accountable for all aspects of the work.