NPS and infection: Possible etiologies include (1) the post-infection autoimmune process; (2) mast-cell activation induced by inflammation, toxins, or stress; (3) urothelial dysfunction and increased permeability of the urothelium; and (4) neurogenic inflammation resulting in increased urothelial permeability, mast-cell activation, the up-regulation of sensory fibers, the release of inflammatory neuropeptide, and bladder pain [62].