Patients with immunodeficiency, particularly those with hematological
neoplasias and persons treated with immunosuppressive drugs have a considerable tendency to
infection due to opportunist germs.
Infections of the nervous system are relatively rare (0.02%-1%) and the commonest
neoplasms are
lymphomas, especially those of Hodgkin type and
lymphosarcomas. The most frequent
infections are caused by the herpes virus,
meningitis due to Listeria monocytogenes and the
meningitis due to fungi (Aspergillus, Candida and Cryptococcus).
Cerebral abscesses, although rarer, are relatively common and are caused by gram negative bacteria, fungi and
toxoplasmosis. In recent years there has been a notable increase in the number of patients diagnosed as having
progressive multifocal leukoencephalopathy due to the possibility of carrying out studies to detect the
DNA of the JC virus by polymerase chain reaction techniques. Empirical treatment of patients with neurological
infections and systemic
cancer should be started following the guidelines for immunodepressed patients. The metabolic complications of these patients are mainly due to
hormone overproduction, hydroelectrolytic changes and
vitamin deficits, which in general cause alterations of mental function of the
confusion state type.
CONCLUSION: In all patients with an
infection or metabolic complication involving the nervous system, the presence of a systemic
neoplasm makes it necessary to vary both the diagnostic approach and the empirical therapeutic measures taken.