Neuroimaging and Neurologic Complications after Organ Transplantation

Abstract

Neurologic complications are common after transplantation and affect 30-60% of transplant recipients. The etiology of most of the posttransplant neurologic disorders is related to the opportunistic infections, both systemic and involving central nervous system (CNS), toxicity of immunosuppressive medications, and the metabolic insult created by the underlying primary disease and the transplant procedure. Neuroimaging studies are one of the key tools in the evaluation and enable early diagnosis of neurologic complications in transplant patients, especially posterior reversible leukoencephalopathy syndrome, central pontine myelinolysis, intracerebral hemorrhage, and fungal and bacterial abscesses. Magnetic resonance imaging (MRI) is the preferred technique, but each of the available neuroimaging techniques offers a unique insight into the pathophysiologic mechanisms underlying neurologic complications of transplantation. The role of neuroimaging in this population includes early detection of calcineurin inhibitor neurotoxicity, opportunistic infections, neoplasia, metabolic disorders, or cerebrovascular diseases. In addition, we can monitor longitudinal progression of disease and treatment response.

The Neurology of Solid Organ Transplantation

“…It usually presents late in the posttransplant period, with a median onset of 27 months after transplantation manifesting with slowly progressive cognitive impairment, visual symptoms and ataxia in a large series [39]. The classic pattern on neuroimaging shows multiple subcortical white matter lesions without contrast enhancement [38]. Unfortunately, there is no effective antiviral therapy for PML, and the only treatment strategy is to reduce immunosuppression [39].…”

“…Human herpes virus 6 (HHV-6) is increasingly being recognized as a cause of limbic encephalitis in SOT recipients which may manifest with encephalopathy, amnesia, and/or seizures [36,37]. Neuroimaging studies often demonstrate characteristic bilateral involvement of the mesial temporal lobes; however, imaging studies may be normal and cannot substitute for cerebrospinal fluid testing [36,38].…”

Central Nervous System Infections in Cancer Patients and Hematopoietic Stem Cell Transplant Recipients

“…2a); however, this may not be the case in acute or subacute cases. Because aspergillosis is a vasoinvasive pathogen, evidence of hemorrhagic brain infarction may also be seen on neuroimaging studies [112]. One group of investigators have suggested that ''target-like'' lesions on DWI may aid in distinguishing Aspergillus from other fungal causes of brain abscess and malignancy [113].…”

Neurologic Complications of Renal Transplant

“…4,5 Neurologic complications can be related to surgical procedures, immunosuppression after transplant (including opportunistic infections or neurotoxicity of drugs), metabolic disturbances, malignancies, and stroke. [6][7][8] A common neurologic complication of kidney transplant at our hospital was femoral neuropathy (Table 1), similar to previous reports.…”