Editorial Comment on: U. Zaleska-Dorobisz, A. Biel, D. Sokołowska-Dąbek, C. Olchowy, M. Łasecki Ultrasonography in the diagnosis of hemorrhagic cystitis – a complication of bone marrow transplantation in pediatric oncology patients

Hemorrhagic cystitis (HC) is a well-documented adverse event concerning patients after transplantation of hematopoetic stem cell. This frequent complication is the result of cyclophosphamide and its metabolites activity, that do damage the mucosa of the urinary bladder. HC has high morbidity, can lead to renal complications, prolonged hospitalization, increased health-care costs, and occasionally can contribute to death. Acute HC is a diffuse inflammatory condition of urinary bladder presenting with bleeding from bladder mucosa.

Focal or diffuse thickening of the bladder wall is a common imaging finding. Blood clots on sloughed mucosa may be seen within the lumen of the bladder. The diagnosis is based on typical clinical and/or ultrasound features.

In 1989, Brugieres et al. published a paper: “Hemorrhagic cystitis following high-dose chemotherapy and bone marrow transplantation in children with malignancies: incidence, clinical course, and outcome”⁽¹⁾. Pery et al.⁽²⁾ presented ultrasound findings in Schönlein-Henoch purpura. They both found macroscopic haematuria in the course of haemorrhagic cystitis. The urinary bladder showed transient mucosal thickening.

In “Pediatric Radiology”, McCarville et al.⁽³⁾ evaluated and reviewed imaging findings seen in kidneys and bladder, and compared them using various imaging modalities. Authors have also highlighted an important role of radiologist in making an early diagnosis, before setting up oncological therapy. Focal or diffuse wall thickening combined with haematuria is a typical presentation of acute cystitis. After these reports, several papers regarding post transplant complications in children were published.

Cheuk et al.⁽⁴⁾, Hong Kong University, declared that HC is a serious complication of hematopoetic stem cell transplantation in children. The incidence could be relatively high – ranging from 3,6% to 25%. The most frequent cause were viral infections: polyomavirus, cytomegaliavirus and adenovirus.

In a multicenter study in 2003, Cesaro et al.⁽⁵⁾ basing on evaluation of over 1200 cases of HC in children after hematopoetic stem cell transplantation, recommended hyperbaric oxygen therapy for better results in postoperative care. This was published in the paper: “Incidence and treatment of hemorrhagic cystitis in children given hematopoietic stem cell transplantation: a survey from the Italian association of pediatric hematology oncology–bone marrow transplantation group.”

Urszula Zaleska-Dorobisz et al.⁽⁶⁾ has examined relative high number of pediatric patients which is important for better evaluation. The Introduction and Discussion are very good and informative. The Material and methods part is correct and supports the results. The Author emphasizes the role of ultrasound technique in evaluating the severity of the disease and its clinical manifestations.

Early detection of oncological treatment side effects will certainly be useful for clinical pratice.

As for the follow up, I suggest complication and remission monitoring. However, I have some remarks.

Firstly, in the Result part regarding various donors, it is not clear enough which group need the most aggressive treatment. Secondly, viral infection is one of the most important causes of HC, which is evaluated by the Author thoroughly. But at this point, I have to comment on the page 269 content: beyond “nephrotoxic virus including BKV” the Author mentions other types of viruses: polyoma BK and JC human virus: “They belong to a family of viruses known as Papovaviridae group^(30–32). Much more rarely, patients with hemorrhagic cystitis are diagnosed with other viruses, such as JCV, ADV or SV-40^(15,33)”. Some of them are easily recognised, the other does not. Does the terms: BK virus, BKV and polyoma BK mean the same? Maybe it is necessary to use same terminology it in the text.

These remarks apply to small part of the material. Otherwise, in my humble opinion, the presented work is excellent.