Final answer:
The nurse should acknowledge the family's feelings of denial, support them through their initial grief response, and help streamline further actions such as additional tests, treatment options, or genetic counseling if required.
Step-by-step explanation:
The first step the nurse should take in assisting the family of a young adult client who has been diagnosed with a rapidly progressing terminal illness is to empathize with their initial reaction, which is likely one of denial. Denial is a common first stage in the five stages of grief identified by Elizabeth Kü bler-Ross. It is important to provide support and understanding as the family processes this information. The nurse should validate the family's feelings without dismissing their hope, but also gently encourage them to consider the possibility of the diagnosis being accurate.
Regarding further actions, the medical team should discuss any additional tests that may be needed to confirm the diagnosis and consider the type of treatment appropriate for the condition, taking into account the individual's specific health situation and preferences. Relevant family medical history should also be discussed, possibly involving a genetic counselor if there is a notable incidence of cancers or other inherited conditions in the family.