Oman Journal of Ophthalmology

EDITORIAL
Year
: 2022  |  Volume : 15  |  Issue : 1  |  Page : 1--2

Cytomegalovirus retinitis in children post hematopoietic stem cell transplantation: Can we develop a screening protocol?


Nouf Al-Farsi1, Samira Al Jabri2,  
1 Department of Ophthalmology, Sultan Qaboos University Hospital, Seeb, Oman
2 Ophthalmology Residency Program, Oman Medical Speciality Board, Muscat, Oman

Correspondence Address:
Dr. Nouf Al-Farsi
Department of Ophthalmology, Sultan Qaboos University Hospital, P.O. Box 38, PC 123, Al Koud, Seeb
Oman




How to cite this article:
Al-Farsi N, Al Jabri S. Cytomegalovirus retinitis in children post hematopoietic stem cell transplantation: Can we develop a screening protocol?.Oman J Ophthalmol 2022;15:1-2


How to cite this URL:
Al-Farsi N, Al Jabri S. Cytomegalovirus retinitis in children post hematopoietic stem cell transplantation: Can we develop a screening protocol?. Oman J Ophthalmol [serial online] 2022 [cited 2022 May 23 ];15:1-2
Available from: https://www.ojoonline.org/text.asp?2022/15/1/1/338879


Full Text



Cytomegalovirus retinitis (CMVR) is a severe retinal disease that is frequently associated with vision loss in immunocompromised patients if not promptly diagnosed and treated.[1] CMVR is the result of hematogenous spread of the virus to the retina after systemic reactivation of a latent cytomegalovirus (CMV) infection.[2]

In recent years, hematological disorders have been effectively treated with hematopoietic stem cell transplantation (HSCT). Hematopoietic stem cells are administered to patients whose bone marrow is depleted or dysfunctional. Depending on the disease being treated, this enhances bone marrow function. This can either destroy tumor cells with malignancy or generate functional cells that can replace dysfunctional cells in cases such as immune deficiency syndromes and hemoglobinopathies. There are different types of HSCT, including autologous where the patient's own stem cells are used compared to allogenic where stem cells come from a donor.[3]

However, allo-HSCT patients are frequently immunosuppressed, and a lack of adequate cellular immunity after allogeneic hematopoietic stem cell transplantation can result in CMV reactivation. Potentially manifesting as gastroenteritis, pneumonia, encephalitis, colitis, hepatitis, and retinitis.

Patients post-HSCT have a higher risk of CMV disease including CMVR with an incidence ranging from 0.2% to 5.6%.[1] In a retrospective study that was conducted at University College London, over 5 years CMVR was developed in 13 (4%) of 304 HSCT recipients (age range, 0.5–197 months).[4] In another study conducted by the University San Raffaele (Milan), for 14 years and a total number of 577 patients, only 10 patients (1.7%) developed CMVR.[5]

The early stages of CMV retinitis are usually insidious and asymptomatic, especially for young children who are less able to recognize and report symptoms. Which contributes to its delayed diagnosis. However, if left untreated, CMV retinitis is capable of causing permanent vision loss. Despite the well-described diagnosis and management of CMV retinitis in the HIV-positive population, further investigation is needed into how this disease should be screened and managed in the pediatric hematopoietic stem cell transplant (HSCT) population.[6]

Studies have shown that the diagnosis of active CMVR was at a median of 199 days (range, −9–541) after HSCT, compared with 77 days (range, −10–426) for nonretinitis diseases (P < 0.05).[4] In another study, the median duration from onset of viremia until the diagnosis of CMV retinitis was 147 days (range 21–280 days).[5]

In these studies, the high incidence of retinitis, the long period between diagnosis of viremia and diagnosis of retinitis, and the lack of associated symptoms in a significant proportion of cases highlight the need for a standardized screening protocol for CMV retinitis in immunocompromised patients.

However, subtle retinal findings, lack of visual symptoms, and the absence of viremia at the time of retinitis can make an early diagnosis challenging.

These challenges can be overcome by keeping a high level of suspicion for CMV retinitis and performing a serial fundoscopic examination by an ophthalmologist. Furthermore, disease-related risk factors should be taken into consideration to determine the frequency of fundus examinations. The risk factors of CMV retinitis post-HSCT that have been studied thoroughly includes, HLA-mismatched donors, HSCT recipients from unrelated donors, preexisting CMV viremia in donor or recipient, peak viral load, and prolonged viremia. All these factors have shown a higher incidence of CMV retinitis. Considering the mentioned risk factors to formalize a screening protocol will result in reducing the burden of unnecessary examinations of a vulnerable population.[6]

A suggested screening protocol by children hospital of Colorado included a baseline examination of vision and a fundus photo before HSCT. After transplantation, patients should be screened depending on the CMV viremia status, if a patient is positive then new baseline dilated fundus exam (DFE) and fundus photo within 2 weeks of identification of viremia should be performed. Then, DFE should be repeated more frequently compared to patients whose CMV status is negative. If any visual complaints were reported by the patient, examination should be repeated immediately. One year is thought to be an adequate period to follow up in patients with CMV retinitis.[7]

Such a protocol implies a huge burden on ophthalmological departments in BMT centers due to the frequency of examination. It has been suggested that the use of peripheral retinal fundus camera can alleviate the pressure as it can be operated by technicians and the photos can be reviewed later by an ophthalmologist. A fundus exam can be planned later if needed. This will make such examinations faster, easier, and more comfortable to the patients and families. However, the cost of this camera and the sick unstable children will remain to keep repeated DFEs as the gold standard.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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4Hiwarkar P, Gajdosova E, Qasim W, Worth A, Breuer J, Chiesa R, et al. Frequent occurrence of cytomegalovirus retinitis during immune reconstitution warrants regular ophthalmic screening in high-risk pediatric allogeneic hematopoietic stem cell transplant recipients. Clin Infect Dis 2014;58:1700-6.
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6Larochelle MB, Phan R, Craddock J, Abzug MJ, Curtis D, Robinson CC, et al. Cytomegalovirus retinitis in pediatric stem cell transplants: Report of a recent cluster and the development of a screening protocol. Am J Ophthalmol 2017;175:8-15.
7Yan CH, Wang Y, Mo XD, Sun YQ, Wang FR, Fu HX, et al. Incidence, risk factors, and outcomes of cytomegalovirus retinitis after haploidentical hematopoietic stem cell transplantation. Bone Marrow Transplant 2020;55:1147-60.