There are a variety of tests used to find out what's happening in the gut. Your healthcare adviser will assess what tests you need. Here is a selection.
The doctor or healthcare adviser will want to do a physical examination. They'll feel your stomach or abdomen for lumps and place pressure around that area to see if you feel any pain.
They'll probably have a look at the perianal area, which is the outside of your back passage, and the pelvic or vaginal area, to see if there's any scarring from tears or cuts, such as that caused by childbirth or surgery. They'll also examine the skin for irritation.
He or she might examine the sphincter muscles. This will involve putting gloved fingers into the anus and asking you to squeeze the muscles around it. This will help determine whether you've got any muscle strength problems or thickening of the sphincter.
This digital examination can also help find any abnormality in the structure of the anus or rectum, such as prolapse, haemorrhoids or signs of a tumour. It can also help identify if there's any impaction, which is faeces that's stuck in the rectum.
You might also be asked to go the toilet and to strain to see if there are any abnormalities such as prolapse.
This physical examination might also test your muscles' reflexes to see if there's any nerve damage.
Testing muscles, sensation and nerves
Anal manometry uses a small balloon-like device to test the squeeze and resting pressure of muscles. The deflated balloon is put into the anus and then inflated. This also helps test reflexes and sensations.
Anal and rectal ultrasound uses the echoes from sound waves to create an image of the rectum, the sphincter muscles and surrounding tissue.
During the anal ultrasound, a thin probe that emits sound waves is put into the anus.
The rectal ultrasound requires a longer probe that goes into the rectum and can also test rectal sensation.
Magnetic resonance imaging (MRI) is another technique used to take pictures inside the body and can help establish the degree of sphincter injury. MRI uses magnets and radio waves to create pictures. Neither ultrasound nor MRI use radiation.
Anal electromyography tests nerve function. It uses electrical impulses to stimulate the muscles and test how well they and the nerves react.
Ways of looking at the colon
There are several ways of looking at the colon.
A conventional colonoscopy is done by putting a tiny camera into the anus and threading it up to the colon. This camera is housed in a long, thin tube. The instrument is called a colonoscope. It can be either flexible, so it can go around bends, or rigid.
The doctor uses it to look at the colon wall and identify inflammation, or lumps and bumps, such as polyps (bulging lumps in the tissue) or tumours. During this procedure, the doctor can remove lumps or tissue.
A sigmoidoscopy (using a proctosigmoidoscope) is similar to a conventional colonoscopy but only looks at the lowest portions of the colon which are the rectum and sigmoid colon.
Sometimes a barium enema is used before the colonoscopy. An enema is when fluid is pumped into the rectum. In this case, the walls of the colon are coated with barium salts which make X-rays clearer.
A virtual colonoscopy uses a CT scanner, which is a computer-assisted X-ray machine, to see into the colon by taking pictures from the outside. If any lumps are found a conventional colonoscopy procedure is then used to remove them.