Nontraumatic central nervous system (CNS) dysfunction is one of the most common emergencies facing an emergency physician. It has been estimated that approximately 10% of patients admitted to the hospital have an altered mental status. <sup>2 Barish R.A., Young J., Whye D. Altered consciousness and syncope Diagnostic Radiology in Emergency Medicine St. Louis: Mosby-Year Book (1992).  391

Cliccare qui per andare alla sezione Riferimenti</sup> Most patients with acute CNS dysfunction can be conveniently divided into two major groups: those who have as the cause of their dysfunction a metabolic or toxic cause (65%), and those whose dysfunction is due to a focal structural cause (33%). A small number of patients (2%) will have as the ultimate cause of their dysfunction a primary psychiatric disorder. <sup>2 Barish R.A., Young J., Whye D. Altered consciousness and syncope Diagnostic Radiology in Emergency Medicine St. Louis: Mosby-Year Book (1992).  391

Cliccare qui per andare alla sezione Riferimenti</sup>

The differential diagnosis of diffuse metabolic or toxic causes of CNS dysfunction is vast (Table 1). The history, physical examination, and judicious use of the laboratory may help the physician in arriving at the correct diagnosis when determining that the cause for the alteration in mental status is due to a metabolic or toxic disorder. The management of these patients is primarily medical.

The physical examination, with particular attention to the general neurologic examination and mental status, may help in determining the cause or location of the structural lesion causing the alteration in mental status. Evaluation of the cranial nerves, motor and sensory examination, cerebellar function, and reflex components complete the neurologic examination. Full mental status evaluation to include cognitive function, affect, thought processes, and mood may offer subtle clues to structural or metabolic derangement of the CNS which may be easily overlooked if the physician only relies on a cursory evaluation.