Gastroenterologist

[Luac]

I had an appointment with a gastroenterologist yesterday who didnt say much but listened attentively as i listed off symptoms. He took lots of notes as I spoke.

I have some bowel issues which my gp thought might be an indication of malabsorption.

These may or may not be connected to the b12 deficiency.

I brought that up and listed those symptoms as well.

There wasnt much discussion but he said I should have a CT scan and a camera in to have a look. I will submit a 24 hour urine sample and a stool sample.

I have no idea what to expect from these but I would like some advice in order to maximise the exploration.

What questions should I be asking? What areas have gastroenterologists typically neglected?

I have been self-injecting every second day for about six weeks now. I notice a difference in that there is less brain fog and less energy drain and pins and needles are really infrequent and minor. I took a four day gap last week by accident and i noticed how tired and confused i got again very quick.

I started high blood pressure medication yesterday, I am supposing that the hypertension is unrelated to the b12 injections although I have noticed more facial flushing recently (before starting BP tablets), particularly with alcohol.

[fbirder]

My guess is that he is aware of the increased incidence of Neuroendocrine Tumours (NETs) in people with PA.

I was diagnosed with gastric NETs in 2015 after a gastroscopy showed strange looking patches of stomach lining with unusual histology (looking at cells) of the tissue samples taken during a biopsy. I had A CT scan (to see if they'd spread), a colonoscopy (to see if they were there) and a 24 hr urine test looking for something called indole acetic acid (IAA - which these tumours secrete). Nothing.

This was the first time my gastroenterologist had had a case of NETs (they are rare) so he decided to send me for a gamma-ray scan (using something called Octreotide) and a PET-MRI (using Dotatate). Nothing.

My current treatment is to have an other gastroscopy every two years (was every year) just to make sure they aren't going anything they shouldn't be doing.

These tumours are caused by the autoimmune gastric atrophy that causes PA.

The immune system attacks cells in the stomach called Gastric Parietal Cells. These make Intrinsic Factor (needed to absorb B12) and stomach acid. without GPCs you cannot absorb B12 and you have no stomach acid (achlorhydria).

Normally, when you eat food your body makes a hormone called gastrin. The increased levels of gastrin in the blood result in the release of stomach acid. This lowers the pH of the stomach contents and this lowering of pH stops gastrin production.

But, with achlorhydria there is no stomach acid, the pH stays high and gastrin production isn't switched off. This results in high levels of gastrin (hypergastrinaemia).

As well as switching on acid production, gastrin does other things. One of these is to promote the development of enterochromaffin-like cells. With hypergastrinaemia these cells produce at a faster rate than normal. And sometimes this faster production goes wrong - and you get a Neuroendocrine Tumour.

They are nearly always indolent. They sit there and do nothing. Rarely they can metastasise or turn into proper cancer. That's why it's a good idea to check to see if you have NETs if you have PA.