Management of the complications of long-term venous access

A syncope is defined as a sudden, temporary loss of consciousness, associated with loss of postural tone with spontaneous recovery. The incidence is high and the differential diagnosis broad; therefore, the first observations are essential for the management of the patient. In this review diseases will be described which manifest themselves with syncopes that fall under the auspices of either internal medicine or neurology. First, the etiologies of syncopes are discussed in the strict sense of the word, i.e. due to a global cerebral ischemia such as in orthostatic hypotension and vasopressor syncopes. Thereafter, a discussion concerning the differential diagnosis of syncopes will be introduced, including mainly psychogenic and epileptic seizures as well as vertebrobasilar hypoperfusion. Depending on the reason of the loss of consciousness, it can be a common benign disorder or a severe life-threatening disease. The personal history or witness account of the incidence provides the most useful information concerning diagnosis. The cardiological diagnostic procedures are discussed elsewhere. In some instances an EEG can further help with the diagnosis. In many cases an etiology can't be found, even if extensive investigations have been performed.