How do you manage refractory hyponatremia in patients on active therapy in small cell lung cancer?

The classic teaching is that if this is a paraneoplastic SIADH then treat the underlying cancer. If hyponatremia is worsening despite treatment, it might herald progression. I have used tolvaptan in the past as bridge but without effective treatment, this is likely not going to be very effective. Of course, need to work up hyponatremia to make sure no other factors are involved.