Dysentry & Constipation. To see reality?

My mother aged 57 is going through a peculiar case of Dysentery then turned into severe constipation which appears every year. My mother also has anal fissure. It is going for the past 2 Years. Previously the dysentery issue gets healed within two days coz my mother used to take metrogyl thrice in a day. Right now its not happening. Last it happend during april - may 2015. I took her to the nearest health center and she took some medicine and suddenly it turns into constipation as she was not able to poop for three days then I arranged a nurse and she gave the manual doose and then all went OK. This year as well same thing happend. This time we choose homeopathy but the same thing happend again. As she also have anal fissure, situation gets worsen every time. I am kind of clueless. Every time she is in pain when this happen and I can't see that. Please suggest me some valuable advice. Should I go for a lower abdomen USG to see reality?