key: cord-0042588-r4vi7osz
authors: Lamps, Laura W.
title: Miscellaneous Enteric Viruses
date: 2009-05-13
journal: Surgical Pathology of the Gastrointestinal System: Bacterial, Fungal, Viral, and Parasitic Infections
DOI: 10.1007/978-1-4419-0861-2_23
sha: 32f0bb3946a91696f7fcf373247909ee86d629df
doc_id: 42588
cord_uid: r4vi7osz

Acute viral gastroenteritis is second only to the common cold as a cause of illness in the United States. It often occurs in outbreaks, sometimes associated with food or water, and is a major recurrent problem in public health. Although most infections are self-limited, viral gastroenteritis can cause severe dehydration (particularly rotavirus), as well as chronic diarrhea in children with immunodeficiency syndromes such as severe combined immunodeficiency. Enteric viral infections are also a significant cause of diarrhea in patients with AIDS. Similar to adenovirus, rotavirus and enterovirus are associated with intussusception in children.

Acute viral gastroenteritis is second only to the common cold as a cause of illness in the United States. It often occurs in outbreaks, sometimes associated with food or water, and is a major recurrent problem in public health. Although most infections are self-limited, viral gastroenteritis can cause severe dehydration (particularly rotavirus), as well as chronic diarrhea in children with immunodeficiency syndromes such as severe combined immunodeficiency. Enteric viral infections are also a significant cause of diarrhea in patients with AIDS. Similar to adenovirus, rotavirus and enterovirus are associated with intussusception in children.

Many enteric viruses do not cause disease in humans; others seldom if ever cross the stage of the surgical pathologist, as they are detected in stool samples rather than biopsy specimens. Common enteric viruses known to cause diarrhea in humans include, but are not limited to, adenovirus, rotavirus, coronavirus, astrovirus, Norwalk virus and other enteric caliciviruses, and echovirus and other enteroviruses Table 23 .1). Interestingly, enteric involvement has been documented in the coronavirus-associated severe acute respiratory syndrome (SARS), and diarrhea was a common presenting symptom in that outbreak. Pathologic findings. Many surgical pathologists are unfamiliar with the non-specific biopsy findings of viral enteritis, as we so rarely encounter these specimens. Pathologic studies are limited, and may not reflect the spectrum of changes in mild illness since most biopsy specimens are obtained from relatively sick patients.

Small bowel biopsy findings include villous fusion, broadening, and blunting (Figs. 23.1, 23.2, and 23.3); crypt hypertrophy ( Fig. 23.4) ; and an increased mononuclear cell infiltrate within the lamina propria with variably present neutrophils (Fig. 23.5 ). There may be an increase in intraepithelial lymphocytes as well (Fig. 23.6 ). Reactive and degenerative epithelial changes are usually present, particularly at the surface, including epithelial cell disarray and loss of nuclear polarity (Figs. 23.7 and 23.8). Increased apoptosis may be seen in surface and glandular epithelium. In the limited number of human studies available, the severity of the histologic lesion does not appear to correlate with clinical Differential diagnosis. The differential diagnosis includes celiac disease, NSAID injury, and peptic ulcer disease. The histologic changes in viral enteritis rapidly return to normal as the patient's symptoms abate, and serologic assays for celiac disease should be negative. Peptic ulcer disease usually features more neutrophils and active inflammation than 

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