Continuum, April 2006, Volume 12, Issue 2

Subacute and chronic meningitis represent only about 10% of all infections of the central nervous system (CNS), but with a growing population of immunocompromised patients their frequency is increasing. The number of recognized etiologies that cause chronic meningitis is also increasing, making it more difficult to establish the diagnosis. In broad terms, chronic meningitis can be divided into infectious causes, which include viruses, bacteria, Rickettsia, fungi, and parasites; and noninfectious causes, which include neoplastic meningitis, CNS vasculitis, and chemical meningitis. This chapter describes an efficient approach to patients with chronic meningitis. The steps involved are: (1) Obtain a careful history with attention to country of origin, recent travel history, other acquaintances with similar symptoms, exposure to unusual animals, and patient's immune status. (2) A careful general physical examination should search for body areas, including lungs, liver, joints, and skin that may be involved, suggesting a systemic illness. (3) The neurological examination should look for signs of cranial nerve palsies, papilledema, and lumbosacral nerve root involvement that give clues as to the areas of CNS involvement. (4)Cerebrospinal fluid should be examined for the type of pleocytosis present, cultured for infectious agents, assayed for infectious agents by polymerase chain reaction, tested for specific antigens, assayed for presence of specific immunoglobulin M (IgM) antibodies, and examined cytologically for malignant cells. (5) Neuroimaging, usually magnetic resonance imaging with gadolinium, should be performed, looking for foci of meningeal enhancement, parenchymal masses, and hydrocephalus. Suspicious body sites that could be infected with the systemic infection, especially lungs and joints, should also be imaged. (6) A tissue biopsy should be considered, especially if a suspicious skin, lung, liver, or kidney lesion is identified. If neuroimaging identifies an enhancing meningeal site, biopsy of the arachnoid and pia mater followed by histological examination may yield the diagnosis.(C) 2006 American Academy of Neurology

Central nervous system (CNS) infections are uncommon but serious complications of solid organ transplantation (SOT) and hematopoietic cell transplantation (HCT). Viral reactivation and opportunistic pathogens are the most frequent causes. Other etiologies include nosocomial exposures, primary infections, and receipt of an infected organ or cells. This review provides an introduction to CNS infections in the transplant population and outlines a framework for evaluation based on type of transplantation, timing, lesion localization, and degree and length of immune suppression. Unique aspects of SOT and HCT are addressed, followed by a description of common pathogens in transplant recipients.(C) 2006 American Academy of Neurology

Clinicians may encounter international travelers returning with exotic infections, emerging infectious diseases, or resurgent old-world infections. Many of these infectious diseases can affect the nervous system directly or indirectly. The contemporary neurologist should therefore be cognizant of the clinical manifestations, potential complications, and appropriate management of common travel-related infections. This chapter focuses on five important infections that affect the central nervous system and that may be encountered in returning travelers: Japanese encephalitis, malaria, rabies, dengue, and neurocysticercosis. The clinical manifestations, suggested evaluation, and treatment are discussed for each infection.(C) 2006 American Academy of Neurology