My Dad has a history (19yrs) of Non Hodgkins lymphoma and had radiation to his back about 1 mo ago. He was recently admitted for headache, fever, and weakness but blood cultures and c-diff were all negative. No neck pain or tenderness either so no menigtis. He is home now and has a fever again of 103 and after taking oxcodone his headache is gone. Is this fever likely from the lymphoma or something infectious going on. I know he is immunocompromised but cultures were negative