Because non-genomic pathways include any mechanism that is not a genomic effect, there are various non-genomic pathways. However, all of these pathways are mediated by some type of steroid hormone receptor found at the plasma membrane.  Ion channels, transporters, G-protein coupled receptors (GPCR), and membrane fluidity have all been shown to be affected by steroid hormones.  Of these, GPCR linked proteins are the most more information on these proteins and pathways, visit the steroid hormone receptor page.
Most modern steroid enemas are foam based - as the likelihood of someone with colitis being able to retain a water based enema is quite low. These act topically applying the steroid directly to the colon - with only small amounts being absorbed into the bloodstream. This makes side effects less likely. The downside is that they can only reach the descending colon and rectum - so for those with extensive colitis oral steroids may be needed. A combination of Entocort and steroid enemas can provide topical treatment to the majority of the colon - again minimizing side effects. As the two main steroid enemas differ quite greatly I will cover them separately.