Autoimmunie Atrophic Gastritis

[Bilbao]

Hi, I'm writing on behalf of my sister. She has had gastro problems for years and 2 years ago it got really bad and has intolerances to many foods. She showed up with very low B12 and has been getting injections ever since. She was only sent for an endoscopy this April. She called Dr surgery after endoscopy and they said everything was fine. Last week she had a follow-up with Gastro in hospital and they suspect she has Autoimmune Atrophic Gastritis, he mentioned that a "flat bit" showed up on the endoscopy and they want to do another endescope and take further biopsies. She is really worried about it and I was wondering if anyone has had similar experience. We are in UK, feel really let down that took 18 months to get referred and then 6 months to get results. Thanks

[fbirder]

The most common cause of a B12 deficiency that isn't caused by diet (vegan/vegetarian) or drugs (PPIs or metformin) is Pernicious Anaemia. And PA is a result of Autoimmune Metaplastic Gastric Atrophy (AMGA). So a lot of us here have it as well.

AMGA is caused by the immune system killing off cells in the stomach called Gastric Parietal Cells (GPCs). This has three main effects -

GPCs produce something called Intrinsic Factor. IF is needed to carry the B12 molecule across the gut wall into the blood (it is too large to get across unaided). AMGA means no IF, which means no B12 is absorbed.

GPCs also produce hydrochloric acid. This is essential for many things. It activates an enzyme that digests proteins. It helps in the digestion of proteins itself. It stops bacteria from surviving in the stomach and invading the small intestine. Without stomach acid some food reaches the large intestine undigested and the bacteria that live there have a big party. This can produce gas, bloating and diarrhoea. (Sounds familiar?)

Many of us find that drinking something acidic (I prefer 30mL lime juice, others swear by apple cider vinegar - but it doesn't taste as good in a margarita) with meals can help a lot.

The final effect of AMGA is caused by the low stomach acid. When you eat food your body produces a hormone called gastrin. This has several useful functions to do with the digestive process - it stimulates the release of stomach acid, the contractions of the stomach itself, secretion of some enzymes and more). In a clever feedback mechanism gastrin production is switched off when the stomach pH drops - which happens when acid is produced.

So, in normal people you eat food, which stimulates gastrin, which stimulates acid, which lowers pH, which switches off gastrin production.

But, if you have AMGA then you don't make acid, so your stomach pH stays high, so gastrin production continues unabated. You end up with high levels of gastrin - hypergastrinaemia.

Another thing that gastrin does is to stimulate growth of cells in part of the stomach (the fundus). WIth lots of gastrin these cells can be overstimulated, which can lead to them forming tumours called Neuroendocrine Tumours (NETs).

Gastric NETs are rare (I have them and I am one in a million). And they tend to be indolent - they sit there doing nothing. But they can sometimes develop into proper gastric cancer.

Your sister almost certainly does not have gastric cancer - they would most likely have spotted it during the first endoscopy. But they probably want to take more biopsy samples to be totally certain. And to rule out NETs.

If she does have NETs then there's nothing to worry about. The doc will probably want to do some scans to check that it hasn't spread (I had CT, gamma ray and PET/MRI scans done - but I think my gastro was just trying them out on me - his first NET patient).

I ended up with an expert at Kings College Hospital, and we agreed that I would have a gastroscopy every year (now every two years) just to keep an eye on the little buggers.

During my research I found a quote for the five-year survival times for people with NETs. For my age group it was longer than for those without NETs (I guess we have better monitoring that will catch other things).

Phew!

tl:dr

Try drinking acidic drinks with large meals (start halfway through and finish at the end of the meal).

Don't worry about the gastroscopy. They're almost certainly just being thorough.

[Bilbao in reply to fbirder]

Hi fbirder, thanks so much for taking the time to reply. I hope this is the case with her. I don't know how long she will wait for the second endoscopy, I will let you know how it goes. Thanks again!

[willijf in reply to fbirder]

Thank you fbirder for the very comprehensive explanation of autoimmune gastritis and NETs. I am also a “one in a million” individual who has had NETs as a result of an overproduction of gastrin. As a matter of fact, my Pernicious Anemia was diagnosed because a NET was found in my stomach. I have an endoscopy once a year now to be safe and It has been a few years since NETs were found. I also drink lemon juice before each meal to aid with digestion and I have eliminated gluten from my diet which has definitely helped reduce gas, bloating, and diarrhea.

[Ashweb901]

It took me 25 years to get an AIAG diagnosis and I had to put all the pieces together myself. There is a great Facebook group called Autoimmune Atrophic Gastritis and Pernicious Anemia. Good info there. And fbirder's reply is also very infromative!