Perdida cerebral de sal: medio siglo de un síndrome no bien definido / Cerebral salt wasting: half a century of a largely undefined syndrome

RESUMO

Peters made the original description of the cerebral salt wasting syndrome (CSWS) in 1950 in three patients with hyponatremia that he assumed to be secondary to natriuresis of cerebral mechanism. Few years later, Schwartz describe the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in two patients with bronchial carcinoma, with characteristics similar to CSWS. Wijdicks gave clinical entity to CSWS when referring that it is the prevalent cause of hyponatremia in patients with subarachnoid hemorrhage, and stressed the risk of secondary cerebral infarction if restrictive plans of water and salt were used as a consequence of a miss diagnosis. However, CSWS has been recently questioned because of its atypical characteristics, not shared by other saline wasting syndromes. The volume status of patients with hyponatremia and natriuresis determines whether the cause of this disorder is SIADH or CSWS. Nevertheless the evidence are contradictory, the vasopressin level can be recognized only in relation to the tonicity of body fluids, and the natriuresis is a common final pathway for both syndromes. In this literature review, some issues of CSWS that are associated or opposed with SIADH and other saline wasting syndrome are discussed. We conclude that the reports that sustain CSWS are insufficient in their methodology and interpretation of the results. The absence of strict metabolic studies has been negatively replaced by the original information casually quoted, and the strength of tradition. Thereafter, the paradigm generates unfounded ethical dilemmas which render difficult any further investigations with appropriate controls.