Leptomeningeal toxoplasmosis after allogeneic marrow transplantation. Case report and review of the literature

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Cerebral toxoplasmosis in an allogeneic peripheral stem cell transplant recipient: case report and review of literature

We present a patient who underwent allogeneic peripheral stem cell transplantation (PSCT) for chronic myelocytic leukemia. Twenty months after the PSCT he experienced status epilepticus. Magnetic resonance imaging (MRI) revealed a focus in the ventral thalamus-hypothalamus region. Using stereotactic biopsy with histology and specific polymerase chain reaction investigation from brain tissue, cerebral toxoplasmosis was diagnosed and treated with antiparasitic therapy. Early recognition of such serious and potentially lethal disease enabled prompt specific treatment. This case report emphasizes the role of stereotactic biopsy in diagnosis of cerebral toxoplasmosis. Other methods such as MRI are non-invasive but not sufficiently specific and sensitive.

Toxoplasmosis after renal transplantation: implications of a missed diagnosis

We describe a renal transplant patient with a primary Toxoplasma gondii infection presenting as pneumonitis, with subsequent chorioretinitis and encephalitis. The diagnostic challenges of T. gondii infection in immunocompromised patients are discussed.

Neurologic complications of bone marrow transplantation

The various forms of HSCT are or will soon be accepted treatments for an ever-increasing number of hematologic and solid cancers. Attempts to reduce the mortality and morbidity of HSCT and at the same time preserve or increase its efficacy in tumor control include development of nonmyeloablative allogeneic stem-cell transplant strategies [208] and allogeneic laboratory research-enhancing graft acceptance [209,210]. Eventually, these efforts will reduce complication rates of HSCT, including neurologic complications. In the interim, the consultant neuro-oncologist or neurologist with a specific inteest in this field is faced with complex clinical syndromes, neuroradiologic imaging studies and neurophysiologic tests, and generally poorly understood pathophysiologic mechanisms. Prospective studies of HSCT patients in large transplantation centers using clinical registries are needed.

Toxoplasmosis in bone marrow transplantation: a report of two cases and systematic review of the literature

Toxoplasma infection represents a rare but often fatal complication in bone marrow transplant (BMT) recipients. We report two cases of toxoplasmosis: one of successfully treated cerebral toxoplasmosis after peripheral blood stem cell transplantation, and a fatal case of pulmonary toxoplasmosis in a BMT recipient. We have systematically reviewed the 110 published cases of toxoplasmosis following BMT. We analyzed the pre-transplant and clinical features of BMT recipients developing toxoplasmosis, together with the diagnostic procedures used and treatment given. By univariate and multivariate statistical analysis we analyzed the risk factors for diagnosis (during life vs post-mortem) and Toxoplasma-related mortality. Ante-mortem diagnosis was made in 47% of cases. Site of infection (P = 0.02; odds ratio 10.8), presence of symptoms at onset (P = 0.01) and conditioning regimen (P = 0.04) were factors influencing whether the diagnosis was made before or after death. Overall mortality rate was 80% and that attributed to toxoplasmosis was 66%. Variables influencing outcome were: site of infection (P = 0.02; odds ratio 5.28), day of onset (P = 0.04) and conditioning regimen (P = 0.04). Underlying disease (P = 0.02; odds ratio 9.45), among patients diagnosed before death, was the most significant factor influencing outcome.

Disseminated toxoplasmosis following T cell-depleted related and unrelated bone marrow transplantation

More than 95% of reported cases of disseminated toxoplasmosis following BMT have occurred following an unmodified transplant. Most have been fatal, diagnosed at autopsy and without antemortem institution of specific therapy. From 1989 to 1999, we identified 10 cases of disseminated toxoplasmosis, in 463 consecutive recipients of a T cell-depleted (TCD) BMT. Transplants were from an unrelated donor (n = 5), an HLA-matched sibling (n = 4) or an HLA-mismatched father (n = 1). In 40%, both the donor and recipient had positive IgG titers against T. gondii pre-transplant; in 30%, only the recipient was sero-positive. Three recipients of an unrelated TCD BMT developed toxoplasmosis despite both donor and host testing negative pretransplant. All 10 patients presented with high grade fever. CNS involvement ultimately occurred in seven patients, with refractory respiratory failure and hypotension developing in nine. Eight of 10 cases were found only at autopsy, involving the lungs (n = 7), heart (n = 5), GI tract (n = 5), brain (n = 8), liver and/or spleen (n = 5). The only survivor, treated on the day of presentation with fever and headache, was diagnosed by detection of T. gondii DNA by polymerase chain reaction (PCR) performed on the blood and spinal fluid. This study demonstrates the similar incidence of toxoplasmosis following TCD BMT and that reported post T cell-replete BMT, and underscores the need for rapid diagnostic tests in an effort to improve outcome.