Autopsy kidneys: an overlooked resource
Chronic kidney disease (CKD) is a global health crisis, with an estimated prevalence of 8-16% worldwide.
We recently conducted a retrospective histologic review of adult autopsy kidneys at our institution in order to 1) establish a baseline of medical renal diseases which the autopsy pathologist can expect to encounter, and 2) determine the incidence of missed diagnoses. In addition to frequent findings of acute tubular injury and arterionephrosclerosis, we detected a wide variety of significant renal pathology in one-third of adult autopsies over a 2-year span.
There are several possible reasons why a pathologist might commit a diagnostic error by overlooking a disease process at autopsy. The primary emphasis during autopsy examination is identification of the immediate cause of death, which results in a more dedicated examination of the organs frequently involved in devastating events (i.e. heart, lungs, and brain). Surgical pathology practices have become increasingly subspecialized, so pathologists are also likely to focus on their organ system(s) of expertise. We also speculate that many pathologists are not adequately trained to recognize medical diseases in autopsy kidney specimens. Our study demonstrates a knowledge gap that needs to be addressed, and also provides a mechanism for addressing it. Autopsy pathology, including medical renal pathology, is a rich educational resource that should be emphasized in residency training.
The deficiency in knowledge regarding renal pathology is most likely due to limited exposure and the current training practices in pathology residency programs. In an effort to address this deficiency in the US, the Accreditation Council for Graduate Medical Education (ACGME) included the requirement of renal pathology in the anatomic pathology curriculum for pathology residents effective July 1, 2015. One of the challenges in developing a renal pathology curriculum to meet the ACGME requirement is the perceived scarcity of teaching material. Medical renal pathology is a small and highly subspecialized field, requiring integration of clinical and laboratory data with light, immunofluorescence, and electron microscopic techniques. Kidney biopsy services and fellowship-trained nephropathologists are typically centralized in large academic pathology departments. Institutions with smaller pathology programs may struggle to develop a renal pathology curriculum. Our study provides one solution to this problem by establishing autopsy kidney specimens as a rich source of medical renal pathology for diagnostic and teaching purposes. In fact, autopsy kidneys likely provide a more accurate picture of the spectrum and frequency of kidney disease in the general population than for-cause renal biopsies. Based on our own departmental experience, we advocate a dedicated renal pathology rotation early in residency training, followed by reinforcement over subsequent years through one-on-one review of autopsy kidneys and the non-neoplastic parenchyma in tumor nephrectomies with renal pathologists. Autopsy kidneys can easily be incorporated into didactic lectures and unknown slide sessions, particularly in residency programs with fewer medical renal biopsies. Our implementation of this curriculum has met with great success and positive feedback.
There are certain challenges to assessment of the kidneys at autopsy, particularly given the desire to minimize costs, and no standard guidelines have been established for their proper evaluation. Several recent reviews have detailed suggested approaches to autopsy renal pathology including gross examination, tissue allocation, and ancillary studies, in addition to medical record review.
Unfortunately, the value placed on the autopsy has declined over the past few decades due to a combination of factors including lack of reimbursement, clinical disinterest, advances in premortem diagnostic techniques, and risk of litigation. Autopsy rates dropped precipitously in the US after the Joint Commission on Accreditation discontinued their hospital autopsy mandate in 1971 and Medicare stopped reimbursement in 1986. Many physicians are concerned that current hospital autopsy rates have declined to approximately 10% of hospital deaths,
Our institutional review highlights a knowledge gap that is pertinent to all practicing pathologists, who should be aware that medical renal disease is common in adult autopsy kidney specimens but is often overlooked. The autopsy has long been recognized for providing important contributions in medical education and quality improvement of care, and autopsy kidney specimens are a valuable source of material to supplement training in anatomic pathology. Furthermore, our understanding of the natural history and pathogenesis of kidney disease will improve with accurate recognition and reporting of kidney diseases at autopsy.