Delirium and quantitative EEG.

reported tongue sores or lip oedema as a putative side effect following BT injection, nor have we ourselves observed similar mucosal reactions in any of our cases. On the other hand, many viruses, predominantly herpes simplex types, varicella zoster and various coxsackie types produce oral manifestations resulting in vesicles or ulcers, or both. Together with enanthemas, these changes may or may not be pathogno-monic for a number of other infectious agents.' Without further information, appearance of tongue sores and lip oedema in this case cannot further be clarified. It seems possible that they had appeared unrelated to a drug reaction as a common or uncommon stomatological infection, with or without upper pharyngeal/respiratory infection.' The authors use the sequence of clinical events and the neurophysiological findings as their main argument for a relationship between BT injections and upper brachial plexopathy. From this sequence, however, the plexopathy could be considered unrelated to the BT injections as well. The following two arguments, however, do not preclude an immune-mediated mechanism for its occurrence. Firstly, plexopathy started with irradiating neck pain that, after a free interval of 23 days, was followed by weakness of selected shoulder and arm muscles. Despite the generally assumed clinical similarity of immune to non-immune forms of brachial plexopa-thy, this interval between pain and onset of weakness is frequently significantly longer in non-immune cases.6 Persistence of pain at the onset of weakness, on the other hand, is seen more frequently in the serogenetic forms.7 Secondly, the haemagglutinin-toxin complex of the Clostridium botulinum type A administered has strong antigenic and biochemical similarities to the toxoid of C. tetani.8 In accordance with everyday neuro-logical experience, however, vaccine-induced plexopathies from the toxoid form of C. tetani are extremely rare.6 Given the worldwide, billion-fold application of tetanus toxoid for many decades, it seems improbable that vaccine-induced complications following BT injections at the peripheral nervous system will occur at a conspiciously higher rate than with tetanus toxoid. BT is a new therapeutic agent with a high level of medical surveillance. Medical observation , therefore, will link any evidence of a possible adverse event to the administration of such an agent; this is even more likely, if the event represents a condition with a generally ill-defined aetiology, such as the non-serogenetic or non-vaccine-induced forms of ("idiopathic") brachial plexopathy.7 Analyses of such cases must take into account selection biases, before further conclusions are drawn. In our opinion, the …