Central nervous system lesions in liver transplant recipients - Prospective assessment of indications for biopsy and implications for management

Background. Precise diagnosis of central nervous system (CNS) lesions in li ver transplant recipients remains problematic. Brain biopsies are often not feasible as a result of coagulopathy. We sought to determine whether selec ted clinical or radiologic characteristics can predict the likely etiology of CNS lesions in liver transplant recipients and thus obviate the need for diagnostic brain biopsies. Methods. A 4-year prospective, observational, cohort study was conducted at liver transplant centers at four geographically diverse medical institutio ns. A total of 1730 consecutive liver transplant recipients were evaluated for CNS lesions; 60 patients with radiologically documented CNS lesions com prised the study sample. Results. Vascular events (52%, 31/60), infections (18%, 11/60), immunosuppr essive associated leukoencephalopathy (12%, 7/60), central pontine myelinol ysis (8%, 5/60), and malignancy (3%, 2/60) were the predominant etiologies of CNS lesions. CNS lesions were most likely to occur within 30 days of tra nsplantation (43%, 26/60); central pontine myelinolysis, subdural hematoma, acute infarcts, and Aspergillus brain abscesses were the predominant etiol ogies during this Lime. All brain abscesses were fungal; 73% (8/11) of thes e patients concurrently had documented extraneural (pulmonary) infection as a result of the same fungal pathogen. Thus, a diagnostic brain biopsy is n ot warranted in these patients. Patients on dialysis were more likely to ha ve ischemic or infectious CNS lesions (P=0.03). Vascular events were more l ikely to occur in repeat transplant recipients (P=0.03). Twenty-five percen t (15/60) of the CNS lesions occurred more than 1 year after transplantatio n; small vessel ischemic lesions, malignancy, or non-Aspergillus fungal bra in abscesses accounted for all such lesions. Conclusions. A presumptive etiologic diagnosis can be established in a vast majority of CNS lesions in liver transplant recipients based on identifiab le presentation that includes time of onset, unique risk factors, and neuro imaging characteristics. Empiric therapy of brain abscesses in liver transp lant recipients should include antifungal and not antibacterial agents.