1. slow metabolism related with hypothyroidism
means slow transit of stool which may result in infection along with use of any medicine containing codeine which may further contribute to constipation
. [any history of the same]
2. if hypothyroidism is the cause make sure it is not Hashimoto's disease which contribute 90% to DV [diverticulosis], check for this Autoimmune disorder with an Endocrinologist
3. after Brain second most important organ is the Gut where thyroid receptors are present and deficiency of the same [hypothyroidism] means you are prone to Coeliac diseases.
4. the best diagnosis is with colonoscopy.
5. in the mean time take gluten free diet and high fibre diet.
PS. muscle cramps
, heat intolerance is one of the ADR [adverse drug effect] of the Levothyroxine
sodium [taken for under active thyroid]