Which statement by a client undergoing a myelogram indicates a contraindication for the test?

The statement indicating a contraindication for a myelogram is the one about the client being allergic to shrimp. This is pertinent because the contrast dye used in a myelogram can be iodine-based, and patients with a shellfish allergy often have a higher risk of having a reaction to iodine as well. It's essential for healthcare providers to identify any allergies, especially to shellfish, as this can lead to serious allergic reactions when contrast agents are administered.

In evaluating the other statements, while they may present potential challenges or concerns in the context of the procedure, they do not outright contraindicate the myelogram. For example, the statement regarding difficulty lying still may complicate the procedure, but it does not necessarily prevent it from being performed with proper strategies in place. Claustrophobia can lead to anxiety during imaging procedures but can often be managed with premedication or sedation. A severe headache after a spinal tap can indicate complications, yet it does not automatically disqualify a person from having a myelogram; instead, medical evaluation would be necessary to assess risk before proceeding.