Table 2.
DISTINGUISHING FEATURES OF SELECT CNS INFECTIONS ASSOCIATED WITH TRANSPLANTATION
| Etiology | Period of Greatest Risk | Common Clinical Features | Neuroimaging Findings on MRI or CT Scanning | Diagnosis |
|---|---|---|---|---|
| Fungal Infections | ||||
| Aspergillus fumigatus | < 1 month | Usually accompanied by pulmonary or gastrointestinal disease | Multiple nonenhancing hypodense lesions in hemispheric grey-white junction or basal ganglia | Identification of branching, often septate hyphae, or positive culture for A. fumigatus in brain tissue or from other site (e.g., lungs) with characteristic brain imaging findings |
| Candida species | Usually accompanied by disseminated disease and fungemia | Often normal | Identification of Candida species in brain tissue or CSF | |
| Cryptococcus neoformans | > 6 months | Fever; headache; altered mental status | Normal; meningeal enhancement or enhancing lesion(cryptococcoma) may be present | Positive CSF culture of C. neoformans; (CrAg) in CSF |
| Parasitic Infections | ||||
| Toxoplasma encephalitis | Fever; headache; altered mental status; seizures; focal neurologic deficit: hemiparesis, ataxia, facial weakness | Solitary or multiple ring-enhancing lesions located in the basal ganglia, deep white matter or hemispheric grey-white junction | Serum anti-Toxoplasma IgG antibody usually present; definitive diagnosis by identificatior of trophozoiites on brain biopsy | |
| Viral Infections | ||||
| CMV | 1–6 months | Mental status changes, psychomotor slowing, cranial nerve palsies, retinitis | Nodular, enhancing ventriculoencephalitis | CSF PCR for CMV sensitive and specific; brain biopsy |
| HHV-6 | < 3 months | Mental status changes, seizures, cranial nerve deficits | Focal or diffuse encephalitis | Primary infection is distinguished from reactivation by absence of serum IgG; viremi (either by blood culture or PCR of plasma, serum or CSF) diagnostic of active infection. |
| VZV | < 6 months | Disseminated infection; Zoster; encephalitis: may present without cutaneous involvement; headache, confusion and somnolence, | May be a mixture of ischemic or hemorrhagic infarcts and demyelinating lesions, often at grey-white matter junction | CSF PCR for VZV is sensitive and specific; brain biopsy |
| (PTLD) (Epstein-Barr Virus) | > 6 months | Mental status change, hemiparesis, or other focal neurologic deficit | Focal lesion with variable enhancement; may have associated hemorrhage or leptomeningeal spread | CSF PCR for Epstein-Barr virus sensitive and specific; brain biopsy More than 500 copies of EBV per 105 lymphocytes correlates with diagnosis |
| Progressive multifocal leukoencephalopathy (JC Virus) | > 6 months | Mental status changes, visual field deficits, focal neurologic deficit | Solitary or multiple nonenhancing white matter lesions on CT scanning or MRI lesions most often in parieto-occipital region | CSF PCR for JC virus is sensitive and specific; brain biopsy |
| Bacterial Infections | ||||
| M. tuberculosis of CNS | < 1 month or > 6 months | Headache, fever, and malaise, meningismus, cranial nerve deficits, and mental status changes. | Ring-enhancing or nonenhancing lesions. | Lymphocytic pleocytosis, hypoglycorrhachia increased protein, or elevated ADA. AFB smear positive in 37% of initial CSF exam, but 87% if four serial samples examined. |