Cerebral Salt-Wasting Syndrome Clinical Presentation

Updated: Apr 19, 2022
  • Author: Sudha Garimella, MBBS; Chief Editor: Sasigarn A Bowden, MD, FAAP  more...
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Hyponatremia and cerebral salt-wasting syndrome

As the decline in serum sodium concentration reduces serum osmolality, a tonicity gradient develops across the blood-brain barrier that causes cerebral edema. Symptoms include lethargy, agitation, headache, altered consciousness, seizures, and coma. [16]

The severity of symptoms typically reflects the magnitude and rapidity of the decrease in serum sodium concentration.

Intravascular volume depletion

Historical features suggesting hypovolemia include thirst, abrupt weight loss, decreasing urinary frequency, and negative fluid balance.


Physical Examination

Physical signs of cerebral salt-wasting syndrome (renal salt wasting) include those associated with severe hyponatremia or intravascular volume depletion.

Hyponatremia can be indicated by acute CNS dysfunction, such as altered mental status, seizures, and coma.

The differentiation of SIADH from cerebral salt-wasting syndrome depends on an accurate estimation of extracellular volume. Unfortunately, no single physical finding can accurately and reproducibly measure effective circulating volume. Commonly used signs of hypovolemia include orthostatic tachycardia or hypotension, increased capillary refill time, increased skin turgor, dry mucous membranes, and a sunken anterior fontanelle. These signs usually appear only when the degree of dehydration is moderate to severe. Central venous pressure may be an unreliable determinant of extracellular volume.