What's a fecal impaction? Is it causes by constipation? And what can you do if someone has it?

The cause. Fecal impaction is a relatively common cause of constipation. Generally is a result of dehydration and low fiber and sometimes exacerbated when defecation is avoided for a period of time. Manual disimpaction with a lubricated gloved finger may be necessary. Notably, this can cause diarrhea as well if liquified fecal matter oozes around the impaction.