More on Renal Salt Wasting Without Cerebral Disease

Abstract

Background and objectives: The existence and prevalence of cerebral salt wasting (CSW) or the preferred term, renal salt wasting (RSW), and its differentiation from syndrome of inappropriate antidiuretic hormone (SIADH) have been controversial. This controversy stems from overlapping clinical and laboratory findings and an inability to assess the volume status of these patients. The authors report another case of RSW without clinical cerebral disease and contrast it to SIADH. Design, setting, participants, & measurements: Three patients with hyponatremia, hypouricemia, increased fractional excretion (FE) of urate, urine sodium >20 mmol/L, and concentrated urines were infused with isotonic saline after collection of baseline data.Results: One patient with RSW had pneumonia without cerebral disease and showed increased plasma aldosterone and FEphosphate, and two patients with SIADH had increased blood volume, low plasma renin and aldosterone, and normal FEphosphate. The patient with RSW responded to isotonic saline by excretion of dilute urines, prompt correction of hyponatremia, and normal water loading test after volume repletion. Hypouricemia and increased FEurate persisted after correction of hyponatremia. Two patients with SIADH failed to dilute their urines and remained hyponatremic during 48 and 110 h of saline infusion.Conclusions: The authors demonstrate appropriate stimulation of ADH in RSW. Differences in plasma renin and aldosterone levels and FEphosphate can differentiate RSW from SIADH, as will persistent hypouricemia and increased FEurate after correction of hyponatremia in RSW. FEphosphate was the only contrasting variable at baseline. The authors suggest an approach to treat the hyponatremic patient meeting criteria for SIADH and RSW and changing CSW to the more appropriate term, RSW.

Hyponatremia associated with demyelinating disease of the nervous system

“…Rare cases have been described to have intracranial autoimmune inflammatory diseases such as ADEM [10]. Maesaka et al [11,12] carefully studied CSWS and noted that this condition can occur in patients without cerebral disease, such as acquired immunodeficiency syndrome (AIDS), cancer, or pulmonary disease. For this reason, they favor the term ''renal salt-wasting syndrome'' (RSWS), rather than CSWS.…”

Encefalopatía perdedora de sal en romboencefalitis por listeria

“…Debe prestarse atención a la presencia de cambios ortostáticos en la presión arterial y el pulso, venas yugulares planas, mucosas secas, ascensos en la proteinemia y el hematocrito, pérdida de peso y al balance de fluidos en las hojas de enfermería 1 . Si se considera apropiado puede estimarse el estado de la volemia con procedimientos invasivos o radioisotópicos 14 .…”

“…También se ha comunicado en patologías extracraneanas como infecciones por HIV, enfermedad de Hodgkin, fractura de cadera y carcinomas metastásicos, razón por lo cual se ha sugerido cambiar el nombre de "cerebral salt wasting syndrome" por "renal salt wasting syndrome" 14,20 . La fisiopatología propuesta para explicar la EPS es que existiría una disminución del flujo del sistema nervioso simpático (SNS) al riñón y/o una elevación de factores natriuréticos circulantes 1,8,17 .…”

“…En SIADH se debe al VEC aumentado, en la EPS a la disminución en la reabsorción proximal por el tono simpático reducido y al aumento en la secreción tubular por la estimulación de los receptores V1 por la ADH 18,21 . También se ha encontrado defectos en la reabsorción de fosfatos en el túbulo proximal 14,21 . Los péptidos natriuréticos auricular (ANP) y cerebral (BNP) a menudo están elevados en la EPS.…”

Toward the optimal clinical use of the fraction excretion of solutes in oliguric azotemia

“…More recently other solutes, including urea, uric acid, and lithium, have been investigated with the goal of improvement in the diagnostic ability to distinguish between PRA and ATN. [44][45][46][47][48][49][50][51][52][53][54] In an effort to evaluate these studies and the particular problems with each solute, we will briefly review the physiology of their renal handling in water deprivation states.…”