Which of the following is an appropriate therapy to manage severe AIHA symptoms?

Plasmapheresis is an appropriate therapy for managing severe autoimmune hemolytic anemia (AIHA) symptoms. This therapeutic procedure involves the removal of plasma from the blood, which contains antibodies that may be attacking red blood cells. By eliminating these potentially harmful antibodies from the bloodstream, plasmapheresis can help alleviate symptoms of AIHA, such as fatigue and pallor, and may improve hemoglobin levels.

The other options listed do not specifically address the underlying immune response that leads to AIHA. Dietary changes might support overall health but won't directly impact the autoimmune process. Physical therapy is beneficial for improving strength and mobility but is not a treatment for the hematologic issues related to AIHA. Hydrotherapy may provide comfort and relaxation, yet it does not have a direct effect on the symptoms or management of AIHA. Thus, plasmapheresis stands out as the most effective and targeted therapy for managing severe symptoms associated with this condition.