Psychiatric emergencies (part III): psychiatric symptoms resulting from organic diseases.

An exhaustive review on the organic illnesses presenting with psychiatric manifestations, properly defined pseudopsychiatric emergencies, is presented. A systematic classification of the nu- merous organic causes of psychiatric disorders, based on authors' experience and literature revi- sion, is carefully analysed, and their suitable diag- nostic management in emergency setting is pro- posed. Moreover, the role of bedside ultrasonogra- phy in Emergency Department is emphasized. The underlying pathogenetic mechanisms are separately discussed. A particular significance is given to "neuropsychological studies", displaying the complex connection between the central ner- vous system and the endocrine system. The role of immune system in influencing the central ner- vous system, explaining the model of"sickness be- haviour" in inflammatory disease, is also de- scribed, according to recent reports of "psy- choneuroimmunology". Moreover, the immune- mediated mechanism explaining how neoplasm can influence brain function in the "paraneoplastic syndromes"is shown. In order to facilitate the teaching method, organ- ic illnesses presenting with acute psychic manifes- tations or mimicking specific psychiatric disorders are subdivided into three groups: (1) Endocrine and metabolic disorders and deficiency states; (2) Inter- nal diseases; (3) Neurologic disorders.