defensive circle

[dĭ-fĕnsĭv]
n.
  1. The addition of a secondary disease that limits or arrests the progress of the primary disease, the two diseases exerting a reciprocally antagonistic action.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.