Fatal case of disseminated toxoplasmosis following allogeneic stem cell transplantation in Singapore - a case report and review of literature

Abstract

Toxoplasmosis is a rare but potentially fatal complication post-allogeneic hematopoietic stem cell transplantation (HSCT), often due to latent reactivation. In Singapore, low seroprevalence limits routine screening and prophylaxis. We report the first reported case of disseminated toxoplasmosis following HSCT in Singapore. A 58-year-old woman with fever and altered mental status two months post-transplant. She had pancytopenia, acute kidney injury, and pneumonitis, with non-specific brain MRI findings. Toxoplasma polymerase chain reaction from serum, bone marrow, and cerebrospinal fluid was positive. Despite treatment with trimethoprim-sulfamethoxazole, pyrimethamine, and sulfadiazine, she developed seizures, intracranial haemorrhage, and nosocomial infections, ultimately succumbing one month later. This case potentially highlights the consideration of routine pre-transplant Toxoplasma screening and prevention strategies, even in regions with low seroprevalence.

Keywords: Allogeneic stem cell transplant; Case report; HSCT; Hematopoietic stem cell transplant; Toxoplasmosis.

Fig. 1

Chest radiology of a patient with disseminated toxoplasmosis. (A) Chest radiograph with diffuse bilateral peripheral infiltrates and (B) Computed tomography of the chest showing diffuse bilateral ground glass opacities consistent with bilateral pneumonitis.

Fig. 2

Neuroradiology findings of stem cell transplant recipient with disseminated toxoplasmosis. MRI brain showing multiple scattered FLAIR hyperintense lesions in cerebral (corticomedullary junction) and cerebellar hemispheres (A and B) as well as a left frontal lesion with hyperintense signal on T1-weighted images suggestive of haemorrhage (C). Follow-up CT brain showing a new haemorrhagic lesion at left thalamus (D).