Infectious, metabolic, and endocrine complications

Infections, metabolic, and endocrine disorders are common causes of non-metastatic neurological complications of cancer. Common neurological syndromes (e.g., delirium or focal findings) in patients with cancer often have uncommon causes, so that neurologists unfamiliar with the spectrum of complications of cancer may miss the diagnosis. Moreover, the neurological manifestation often appears in complexes that include: multiple metastatic and nonmetastatic complications such as the side-effects of cancer therapy; nutritional, metabolic, or endocrine disorders; and a superimposed infection. Therefore, the differential diagnosis may sometimes be difficult, and meticulous and sophisticated clinical and laboratory evaluation is required to reach a definitive diagnosis. This chapter describes the high-risk groups of patients with cancer who are prone to develop infectious complications, providing an outline of disease-specific risk factors. This is followed by a description of the main neurological presentations of infection within the central nervous system (CNS) and a more detailed clarification of specific organisms causing CNS infection in patients with cancer. The chapter emphasizes unique clinical syndromes, neuroimaging, and laboratory evaluation as well as pitfalls in diagnosis.Finally, some selected topics related to metabolic complications - mainly electrolyte imbalance, malnutrition, deprivation of specific nutrients, and endocrine disorders - are described. The importance of early and cautious replacement therapy in order to avoid secondary morbidity is emphasized.