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Cytomegalovirus enteritis with ischemia in an immunocompetent patient: A rare case report

Highlights • We report a case of ileal ischemia caused by CMV in an immunocompetent individual.• CMV enteritis is a rare disease in immunocompetent persons.• Diagnosis is mainly based on the histology.• It should be considered in any unwell elderly patient with abdominal pain and diarrhoea.


Introduction
Cytomegalovirus (CMV), a DNA virus and a member of the herpes family, is well known to cause infections in the immunocompromised patients [1]. Its worldwide seropositivity ranges from 45% to 100% [2]. Primary or reactivated infections are typically seen in individuals with acquired immunodeficiency syndrome or in patients undergoing chemotherapy or transplant [3]. CMV can involve specific organs, such as the retina, respiratory tract, central nervous system, and gastrointestinal tract [4].
CMV infection is not a common occurrence in immunocompetent individuals. But common systems involved are the gastrointestinal tract followed by the central nervous system [5]. It can infect the gastrointestinal tract from the oesophagus to the rectum, with the most frequent site being the colon [6]. The occurrence of CMV enteritis is considered to be rare in this group and enteritis leading to ischemia is unheard of.

Presentation of case
A 78-year-old male patient presented to our hospital with colicky central abdominal pain and vomiting. Significant medical history included type 2 diabetes mellitus, chronic obstructive airway disease, and hypertension. The patient had no known history of immunodeficient conditions such as steroid intake, hepatitis B or C, human immunodeficiency virus infection, chemotherapy, or organ transplantation.
Clinical examination revealed distended abdomen with localised peritonism in right lower quadrant. Routine haematology results showed leucocytosis of 15.1 × 10 9 /L (range, 3.5-11.0 × 10 9 /L) with neutrophilia. A computed tomography (CT) scan showed a segment of distal illeum with oedematous and thickened appearance, suggestive of focal enteritis, with some fluid around the associated mesentery (  and ulceration with a marked transition from normal mucosa. Hallmark cytopathic CMV inclusions were present in vascular endothelium of the capillaries and stroma of the ileal segment. Blood cultures did not yield any pathologic organisms. After the surgical procedure, serologic studies were conducted to check the patient's immune system. Human immunodeficiency virus immunologic assays were normal. Cytomegalovirus IgG antibodies were present, and IgM assays were nonreactive.

Outcome and follow-up
The patient received care in an intensive care unit during the postoperative period and was started on intravenous 440 mg ganciclovir for 3 weeks. He then transferred to a transitional care facility for rehabilitation and discharged home after 16 days of uneventful course. He was followed up in surgical clinic after two weeks and subsequently discharged to general practitioner's care in the community.

Discussion
In otherwise immunocompetent individuals, colitis is the most common gastrointestinal manifestation of CMV [8]. The disease cascade is thought to be initiated by changes in vascular endothelium, with resultant ischemic damage to the mucosa of the colon [9]. This may lead to ulceration and ultimately to perforation.
Cases of isolated CMV enteritis are sparsely reported, and, to date, its association with ischemia has not been reported. It is mainly present in patients above 50 years of age [10]. The review of literature on CMV entertitis was done by Karigane et al. The commonest symptom described was diarrhea (76%), followed by abdominal pain (52%). Hematochezia, melena, or bloody stool was described in only 27% of the patients [7]. Complications associated with enteritis are mainly perforation secondary to ileal ulceration.
Diagnosis of enteritis/ileitis has mainly been established on a histological basis with the assistance of colonoscopic biopsies of the terminal ileum. Surgical resection, secondary to complications, is rarely required in the first place [11]. The role of serologic assays is debatable. In most instances, including this case, such tests were requested as an adjunct after confirmation of histology because disease was not suspected earlier [10,11].
As in our reported case, thickening of the ileum on computed tomography scan is a salient feature commonly shown in other cases of CMV enteritis (Fig. 1). In this case, small bowel's mesentery had palpable pulse, which suggested ischemia is at small vessel level. Lack of coexisting colitis was another notable feature. On biopsy, ischemic mucosa was limited to a segment of the ileum only. With the understanding that the small bowel has richer vasculature than the colon, the colon, even in elderly patients, is more susceptible to ischemia than the ileum.
Different serologic tests can be done, including tests for CMV IgM and IgG antibodies and CMV viral load. However, the sensitivity of such investigations has not been fully established. In addition, the role of antigenemia for the diagnosis of CMV gastroenteritis is limited in patients who are on immunosuppressive therapies [12]. Similarly, in our patient, serologic assays were not helpful. Although no obvious risk factors were present, diabetes and old age are relative risks for the immune system's integrity. In elderly patients who are not apparently immunocompromised, CMV should be included in differential diagnosis for gastroenteritis-like diseases.

Conclusion
CMV enteritis should be recognized as a possible disease entity not only in immunocompromised patients but also in some immunocompetent individuals, especially in the elderly with multiple medical conditions. Although its association with ischemia is a rare occurrence, an accumulation of more cases is required to further elucidate the risk factors and optimal surgical treatment.

Conflict of interest
None to declare.

Funding
None.

Ethical approval
Not applicable as per journal policy.

Consent
Informed consent was taken from patient's next to kin.

Author contribution
Z. Naseem formulated concept of study, prepared the manuscript, literature review, editing and image creation.
R. Hendahewa contributed towards intellectual content, conception, literature review and editing.
G. Premaratne was involved in the care of patient and contributed towards intellectual content.
M. Mustaev was involved in editing of the manuscript.

Guarantor
R.H. and Z.N. will act as guarantor of this work.