Case report: Radiographic and cystoscopic manifestations of chronic urogenital Schistosomiasis in an asymptomatic Zimbabwean man with HIV

Abstract

While undergoing evaluation for loss of consciousness and traumatic injuries after a single-vehicle collision, a 55-year-old Zimbabwean man residing in Maryland was incidentally noted to have circumferential bladder wall calcification and thickening on CT imaging. Cystoscopy revealed extensive ‘sandy patches’, confirmed by histopathology to represent calcified eggs of Schistosoma haematobium. Genitourinary symptoms were absent, ova were not identified on urine microscopy, and serum eosinophil level was normal, consistent with the primary infection having occurred at least 20 years prior. While structural and functional genitourinary abnormalities were absent, significant complications can occur even after years of asymptomatic disease.

1. Introduction

Schistosomiasis is a highly prevalent but neglected tropical disease with a complex life cycle involving freshwater snails and mammals, that causes myriad and complex acute and chronic clinical manifestations, immune responses, and tissue pathology in affected humans. Schistosoma mansoni and S. haematobium are endemic in Sub-Saharan Africa, with S. haematobium being most likely to cause urogenital schistosomiasis.1, 2, 3 Patients with prior residence in or travel to endemic areas can present years after exposure with incidental asymptomatic disease, as described in this case report, but remain at life-long risk for urogenital complications.

2. Case report

A 55-year-old man living with HIV was brought to the hospital following a single-vehicle collision due to loss of consciousness and was found to have a brain lesion on MRI. He had been out of HIV care for approximately 1-year but had recently been resumed on antiretroviral therapy (ART), had an HIV RNA below the limit of detection, and had a CD4 cell count of 108 cells/mm³, prompting evaluation for opportunistic infections, immune reconstitution inflammatory syndrome, and malignancies. He was ultimately diagnosed with progressive multifocal leukoencephalopathy (PML) based on JC virus antigen reactivity on immunohistochemical staining of the brain lesion.

During diagnostic imaging to assess for trauma related injuries from the motor vehicle collision, there were incidental findings of circumferential bladder wall thickening and mucosal calcification on CT abdomen/pelvis with intravenous contrast (Fig. 1). Cystoscopy revealed “sandy patches” throughout the bladder mucosa (Fig. 2), correlating with extensive submucosal urothelial calcifications on histology (Fig. 3). He denied history of lower urinary tract symptoms including hematospermia, hematuria, dysuria, and urinary urgency and frequency. He grew up in a rural area of Zimbabwe, where he had regularly swam in freshwater lakes as a child.

Fig. 1.

CT abdomen and pelvis with contrast showing circumferential bladder wall thickening (white arrow) and mucosal calcifications (black arrows).

Fig. 2.

Cystoscopy photograph showing ‘sandy patches’ (black arrows).

Fig. 3.

Bladder histopathology: A) Hemotoxylin & Eosin stain showing urothelial mucosa with extensive submucosal calcifications (black arrows), without granulomas, 400X; B) Ziehl-Neelsen stain showing absence of acid-fast bacilli, 100X.

The patient was diagnosed with sequelae of genitourinary schistosomiasis based on circumferential bladder wall thickening and submucosal calcification, “sandy patches” seen on cystoscopy, and prior residence in an area endemic for Schistosoma haematobium. Genito-urinary tuberculosis was also considered given overlapping features of bladder wall calcification and thickening. This diagnosis was excluded based on negative interferon gamma release assay, negative PET-CT, lack of clinical symptoms of tuberculosis, and histopathology showing no acid-fast bacilli or caseating granulomas.

3. Discussion

Schistosomiasis is a highly prevalent but neglected tropical disease endemic in Sub-Saharan Africa. The portion of the Schistosoma haematobium life cycle occurring in fresh water involves eggs excreted via mammal urine or feces hatching to release miracidia, which penetrate the intermediate host, freshwater snails, and develop into sporocysts which are then released from the snail as free-swimming cercariae larvae. These penetrate the skin of an exposed mammal, causing an acute allergic reaction (‘swimmers itch’ or cercarial dermatitis). As cercariae lose their tails during skin penetration they become schistosomula and enter the lymphatic system, traversing through the thoracic duct, the right heart, the lungs, the left heart, and eventually reach the mesenteric capillaries and enter the portal system. It is here in the liver that adult worms couple and copulate, then travel as a paired unit against venous flow to the vesicular venous plexus. Adult females then release their eggs, with terminal spikes directed towards the bladder lumen. Detrusor contractions push the eggs through the bladder wall into the urine; if this urine meets with fresh water the life cycle begins again 1, 2, 3.

Deposition of the eggs approximately 10–12 weeks after initial cercarial infection elicits the start of a chronic granulomatous reaction that manifests clinically as cystitis with hematuria, hematospermia, and suprapubic pain. Over time, eggs that remain trapped in the bladder wall will die and trigger a more intense cellular immune response with eventual calcification of dead eggs and fibrosis of granulomas, leading to ulcers, fistulas, strictures, obstruction, polyps, urodynamic disorders, infertility, and squamous cell bladder cancer. These complications can arise after years of asymptomatic disease, due to either long term effects of the initial inflammatory damage or surviving helminths and ongoing infection.⁴ Healed areas of calcification and fibrosis can be visualized on cystoscopy as ‘sandy patches’, and on radiographic imaging as linear bladder wall calcifications.1, 2, 3

Though the association with serious urogenital morbidity is well established, most work in Schistosomiasis focuses on prevention of acquisition and mass drug administration in high endemicity areas, rather than long-term monitoring for complications.⁴ As such, large-scale evidence to guide any post-treatment care is absent, but urinary cytology, urinary CEA, ultrasonography, urography, CT, positron emission topography, and cystoscopy have been employed for bladder cancer detection.⁵

This patient had lived outside of an endemic area for 21 years at the time of presentation and did not recall any episodes consistent with cercarial dermatitis or acute genitourinary schistosomiasis, potentially owing to the time lapse, a mild initial presentation, or his current memory deficits from advanced HIV and PML. We believe it is most likely that he contracted and was successfully treated for acute schistosomiasis in childhood, as point estimates of schistosomiasis in Zimbabwe in that time frame were 14.3 %, 37.1 % and 63.2 % in low, medium, and high prevalence zones, respectively, and praziquantel was available and effective.⁶ Infection with S. haematobium is known to increase sexual HIV acquisition, and HIV infection is generally known to increase rates of multiple cancers, but co-infection with HIV and S. haematobium has not been shown to further increase the rate of schistosomiasis-related bladder cancer.⁷

Urine ova screening was negative and serum eosinophil level was normal in this patient, as expected for a remote infection. Even in acute infection, egg yield for S. haematobium is low.⁸ Antibody testing for S. mansoni was negative and for S. haematobium was not available; serology for Schistosoma spp. is significantly limited by feasibility, expense, cross reactivity, and specificity, as exemplified in this case.⁸

Our patient was not treated with praziquantel as he did not have evidence of active infection, and treatment would not reverse the fibrosis process. In the following 2 years after the incidentally noted genitourinary schistosomiasis, he continues to be asymptomatic other than urinary frequency which was attributed to an enlarged prostate. The PML brain lesion resolved with immune reconstitution.

CRediT authorship contribution statement

Harpreet Kaur: Writing – original draft. Talal Alkayali: Writing – original draft. Nathan Williams: Writing – original draft. Sarah A. Schmalzle: Writing – review & editing, Writing – original draft.

Patient consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Funding

None.

Conflicts of interest

None.