Absorption of thyroxine

[Helen59]

I have an Ileostomy and am wondering if anyone has heard or read anything regarding poor absorption of thyroxine with a stoma. I don't know where in the gut Thyroxine is absorbed but I know that some drugs are absorbed in the colon and since I dont have one this can sometimes be a problem.

[Marz]

ncbi.nlm.nih.gov/pubmed/257...

Found this whilst having a look around. Am sure someone will come along with more concrete evidence for you hopefully. I was thinking you could contact the researchers for more information as they are in Ireland.

How are your B12 levels ? I have had a Hemi-colectomy and further resections resulting in B12D.

Your post has certainly set me thinking so am curious

[Helen59 in reply to Marz]

Hi Marz, thanks for that. B12 ok but my ferritin drops regularly and I need iron infusions. I'll have a look at that article.

[Marz in reply to Helen59]

Sorry to be a pest - but what is the OK result of your B12 ? Anything below 500 can cause neurological symptoms - and it needs to be around 900/1000 to prevent cognitive decline. I only mentioned it as B12 is metabolized in the Terminal Ileum and returned to the liver - so was thinking you maybe low. Only 20% of what is in the blood result is available to be utilised in the cells. Docs have little understanding and seem to think we will be fine if just in range

When I had my surgeries over 40 years ago - they forgot to mention I would need B12 injections for life. I started them 18 months ago but doubt the de-myelination of the spinal cord will be healed.....

b12deficiency.info/signs-an...

You can click onto my name to read my 'edited ' profile and to see I am not medically qualified.....

[Helen59 in reply to Marz]

Interesting. Thank you. I don't know what the 'score on the door' was last time, just accepted being told it was within normal range. I'll check that out when I go next month for my routine bloods. I do get quite a lot of pins and needles, amongst other symptoms, and had put it down to my under active thyroid, hence the question re absorption. My dose was increased 3 months ago as levels not right. Think a full discussion with my GP is on the cards, with some up to date advice re B12 from my stoma nurses first.

[Marz in reply to Helen59]

Please always obtain copies of all test results so you can monitor your own progress. Living in Crete we look after our own records However it is your legal right to have copies as part of the Data Protection Act I have read.

You can then post results with ranges here and people will help. Sadly Docs think being in range is good and we all so love the word normal - who doesn't want to be ? We then go weak at the knees with delight and forget to ask for copies of the results WHERE we are in the range is important.

I am also on the PAS forum - here on HU - and the people being mis-diagnosed on a daily basis as their B12 is in range is absolutely heart breaking.

If they test your B12 then also ask for Ferritin - Folate - Iron - VitD to be tested too. They all need to be OPTIMAl and not bumping along the bottom of the range.

Good Luck

[helvella Administrator Thyroid UK]

Perhaps the abstract below would help?

Do be very aware that there is a simple "levothyroxine gets absorbed..." thought process - which is fine as far as it goes. But the body can do some slightly odd things such as making T4-sulphate which will enter the gut and later possibly get re-absorbed. So the TOTAL effect of any unusual gut issues might not be fully explained by the simple absorption described.

Thyroid. 1991 Summer;1(3):241-8.

Localization of human thyroxine absorption.

Hays MT1.

Author information

Abstract

The distribution of intestinal absorption of 131I-labeled thyroxine (T4*) was studied in 4 normal subjects after oral and i.v. T4*, given in separate experimental sessions. In addition to collection of time-activity curves for plasma T4* from the two sessions, distribution and transport of T4* through the gut was quantified by external imaging. Time-activity curves were obtained for the stomach, duodenum, and upper jejunoileum. A multicompartmental model for systemic T4, with three distribution compartments and a single exit route, was employed. Additional, gastrointestinal, compartments were introduced. The stomach data were fitted to a model with three compartments, two for transport and a small sink of gastric activity that does not interact with the absorptive sites. Transfer from the duodenum to the upper jejunoileum and from the upper to the lower jejunoileum was modeled from fits to the peak T4* activities in the images of the duodenum and upper jejunoileum. The rate of transfer from the lower jejunoileum into more distal intestinal sites was fixed, but the impact on the results of using various values for this parameter was analyzed. The model calculations of absorption (mean +/- SD for 3 of the subjects) are duodenum, 15 +/- 5%, upper jejunoileum, 29 +/- 14%, and lower jejunoileum, 24 +/- 11%. The fourth subject, whose global absorption was abnormally low for uncertain reasons, had 17% absorption from the duodenum, 9% from the upper jejunoileum and none from the lower jejunoileum. Model projections mimicking clinical gut abnormalities known to affect T4 absorption were compatible with the results of published studies.

PMID:

1824339

[PubMed - indexed for MEDLINE]

ncbi.nlm.nih.gov/pubmed/182...