What signs should a nurse expect to observe in a client with SIADH due to small cell lung carcinoma?

In a client with Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) related to small cell lung carcinoma, oliguria is a key sign to expect. SIADH leads to excess secretion of antidiuretic hormone, which results in increased reabsorption of water by the kidneys. This can cause dilutional hyponatremia, where sodium levels drop due to the excess fluid in the body.

As the body retains more fluid, urine output typically decreases, leading to oliguria. The body’s attempts to retain electrolytes are contrasted by the excessive fluid retention, making oliguria a notable sign. While other symptoms can occur due to hyponatremia, the primary manifestation of increased water retention is the decreased urine output.

Other options, like seizures, vomiting, and polydipsia, can occur in the context of severe hyponatremia but are not direct manifestations of SIADH itself. For example, seizures may result from critically low sodium levels, and polydipsia may not be present due to the body’s confusion about hydration status as a consequence of fluid overload. Thus, the most direct, observable sign in the scenario of SIADH related to small cell lung carcinoma