This is Dr Basu, experienced Internal Medicine Specialist.
I am here to address your concerns and provide great service.
Rectal muscle spasm without any other problem, is likely idiopathic meaning cause is unknown.
Sometimes tail bone arthritis can cause pressure on the nerves supplying the rectum.
That can cause muscle spasms.
Constipation, hemorrhoids, anal fissure are other possibilities.
Best treatment will be topical nitroglycerine ointment as needed to control the spasms.
Topical diltiazem ointment is another good option.
Botox injection is considered for resistant cases.
You should consult with a colorectal surgeon.
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