Hyponatremia, serum sodium < 135 mEq/L, is the most common electrolyte abnormality and is in a state of flux. Hyponatremic patients are symptomatic and should be treated but our inability to consistently determine the causes of hyponatremia has hampered the delivery of appropriate therapy. This is especially applicable to differentiating syndrome of inappropriate antidiuresis (SIAD) from cerebr...

A 37-year-old woman presented with psychiatric symptoms. Cerebrospinal fluid analysis revealed pleocytosis and increased protein. The patient was diagnosed with limbic encephalitis on the basis of the clinical course. However, remarkable hyponatremia was noted throughout the clinical course, leading to a diagnosis of cerebral salt wasting syndrome (CSWS). The hyponatremia was alleviated by supp...

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 repo...

The kidney and the brain play a major role in maintaining normal homeostasis of the extracellular fluid by neuroendocrine regulation of sodium and water balance. Therefore, disturbances of sodium balance are common in patients with central nervous system (CNS) disorders and clinicians should focus not only on the CNS lesion, but also on the potentially deleterious complications. Hyponatremia is...

Hyponatremia is the commonest electrolyte abnormality in hospitalized patients and occurs due to various causes. Here we present a case of SIADH who was diagnosed using commonly available biochemical tests. This case report also discusses the interaction of the laboratory physician with the treating clinician and the approach needed to arrive at a correct diagnosis. It highlights the importance...