Central Nervous System Infections Associated with Human Immunodeficiency Virus Infection: Radiologic-Pathologic Correlation

Abstract

Diseases of the central nervous system (CNS) in patients infected with the human immunodeficiency virus (HIV) result directly from HIV itself or from a variety of opportunistic agents. These infections include progressive multifocal leukoencephalopathy, toxoplasmosis, and cryptococcosis. A resurgence of tuberculosis and neurosyphilis has also been documented. Mass lesions, meningoencephalitis, demyelination, atrophy, and vascular lesions are the commonly encountered imaging findings. The introduction of highly active antiretroviral therapy (HAART) has improved both the clinical and radiologic findings in HIV-infected patients and reduced the number of opportunistic infections. In countries that use HAART, AIDS (acquired immunodeficiency syndrome) dementia complex is becoming the most common neurologic complication of HIV infection, whereas opportunistic infections are still the major cause of neurologic complications in patients from countries that do not commonly use HAART. Immune reconstitution inflammatory syndrome, which occurs in some patients in the weeks to months after the institution of HAART, may alter the typical imaging appearance of infectious diseases involving the CNS. Knowledge of the spectrum of imaging findings of these infectious diseases, as well as the effect that treatment has on imaging appearances, is important in the evaluation of HIV-infected patients.

White Matter Development is Potentially Influenced in Adolescents with Vertically Transmitted HIV Infections: A Tract-Based Spatial Statistics Study

“…Related studies have demonstrated the predominant pathologic features, including pericapillary multinucleated giant cells, myelin loss, reactive astrocytosis, and microglial activation with microglial nodules. 34 These factors may influence myelination and myelin development. The above findings indicate that the WM integrity may serve as a potential new treatment target for HIV-positive patients, and FA may be used as a qualified biomarker to understand the underlying mechanisms of injury or to evaluate the effectiveness of early interventions in adolescents with vertically transmitted HIV infections.…”

Cryptococcus gattii Infections

“…This abnormality is readily seen on MRI scans, most commonly near the basal ganglia. It is present in almost 50% of cases of HIV-associated cryptococcosis and is a diagnostic clue in such patients (306,307). MRI scans are useful for delineating basilar meningeal enhancement after injection of gadolinium.…”

Solitary Hypothalamopituitary Toxoplasmosis Abscess in a Patient with AIDS

“…Lesions are usually multiple and are solitary in only approximately 14% of cases. 3 A solitary lesion in a patient with AIDS is more likely to be a lymphoma (the second most common cause of space-occupying brain lesions in AIDS) than toxoplasmosis, 4 and imaging appearances can be very similar. Several techniques have been suggested to help differentiate both, including diffusionweighted imaging, 5 MR spectroscopy, single-photon emission CT, and positron-emission tomography.…”

“…The lesion was isointense on T1-weighted sequences, with an asymmetric target sign (a small eccentric nodule along the wall of the enhancing ring) on postcontrast sequences. 3 The pituitary stalk was thickened (Fig 1). A rapid screening test was positive for HIV.…”

“…A rapid screening test was positive for HIV. Examination of blood revealed lymphopenia and 8 CD4 cells/mm 3 . Serum toxoplasma immunoglobulin G was positive.…”