Is my constipation due to thyroid or pelvic floor issues?

Question

Hello doctor,

I am 41 and have been dealing with chronic constipation for the past six months. I usually have bowel movements only two to three times a week and need to strain a lot. I have tried psyllium and milk of magnesia and currently take polyethylene glycol daily. My TSH is 3.6 µIU/mL, and calcium levels are normal.

Could slow digestion still be related to hypothyroidism, even if my TSH is not technically high?
Are there specific tests to check for pelvic floor dysfunction?
What is the difference between regular constipation and colonic inertia?
How is colonic inertia diagnosed?

Please help.

Answer 1

Hi,

Welcome to icliniq.com.

I read your query and can understand your concern.

I know how exhausting chronic constipation (long-term difficulty or infrequent bowel movements) can be, especially when it does not respond to common treatments. You are asking the right questions to help get to the root of the issue, and that is an important first step.

Your TSH level is 3.6 mIU/L, which is technically within the normal range (0.4 to 4.5 mIU/L). However, some guidelines suggest keeping it below 2.5 to 3.0 in people who are experiencing symptoms. What we know is:

TSH (thyroid-stimulating hormone) is produced by your brain to control the thyroid gland. Even a slightly high level may indicate a mildly underactive thyroid (called hypothyroidism), which can lead to slow digestion, fatigue, dry skin, and weight gain.
It may be helpful to check free T4 (the active form of thyroid hormone) and TPO (thyroid peroxidase) antibodies to rule out Hashimoto’s disease, an autoimmune thyroid condition.

There are a few different types of constipation:

Functional constipation: often linked to diet, dehydration, or stress.
Colonic inertia: where the colon moves stool very slowly, causing infrequent urges and poor response to laxatives.
Pelvic floor dysfunction: When the muscles that control bowel movements do not coordinate properly, leading to straining or incomplete emptying.

If PEG (polyethylene glycol) has not helped much, consider asking your doctor about:

Colonic transit study: Checks how fast stool moves through your colon.
Anorectal manometry: Measures how well your rectal muscles work.
Defecography: This shows how your rectum and muscles function during a bowel movement.

In the meantime, continue PEG, stay active, drink plenty of water, use a footstool to aid posture, and consider biofeedback therapy if pelvic floor issues are suspected.

I hope this helps.

Kindly revert so I can assist you further.