Pernicious Anaemia Society
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Macrocytosic should it improve on b12 ?

Hi all

Just joined this forum, quick background. After much misdiagnosis it was confirmed I had auto immuno chronic ulcerative colitis over 20 years age. Medication didn't work and too many STERIODS taken over 10 years i'v been on azathioprine . About 4 years back the gastro team were concerned my my blood results especially the megaloblasts. Tests were done and it was decided it was PA. the cause is either Autoimmune met aplastic strophic gastritis, or the drug is known over time to block or kill intrinsic factor.

I don't remember having the loading dose as I see recommended .i think a had a few b12 injections for 2 weeks then on to 3 monthly. I did ok at first. Due to costs etc, my care was handed back to the Gp, i'v had a few colitis setbacks no back on STERIODS , and continued the 3 monthly 1mg/ml, b12. It's been that way for the last 3 year. Of late I'm struggling one month before and 2 weeks after the recommended b12 dose. Coming to my question. My blood is and always macrocytosic large misshaped red blood cells. Now if my b12 was prescribed because of this anemia why is there no improvement ever. I believe as many that the dosage is insufficient . I and very symptomatic and now have pain in my long bones.

8 Replies

The treatment you're on should fix macrocytic anaemia if it's due to a B12 deficiency. Maybe there's another cause. How's your folate?


It sounds like the doctor needs to monitor/test more closely, doesn't it?


link about macrocytosis.

"i think a had a few b12 injections for 2 weeks then on to 3 monthly."

This reads like the standard UK treatment for b12 deficiency without neuro symptoms.

See page 8 of the "BCSH Cobalamin and Folate Guidelines"

I also found page 29 useful, it shows the recommended process doctors should follow with someone they think has b12 deficiency.

Do you have any neurological symptoms?


In the UK the recommended treatment for those with b12 deficiency with neurological symptoms is loading doses every 2 days until symptoms stop improving then injections every 2 months. details on page 8 BCSH Cobalamin Guidelines.

B12 books

"What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

"Could It Be B12" by Sally Pacholok and JJ. Stuart

I am not a medic just a person who has struggled to get a diagnosis.


Thank you, I have been reading your posts . And I have seen you posts about this advices of others. I'll follow up. I just started Holland and B, multi Vit plus iron,foliage at my Gps advice. Due to my gastric issues its hit and miss what I absorb from tablets and a very rapid colon.

I do have an undiagnosed cough. My profession before retirement was as a respiratory physiologist. I had advice but no cure from the chest physicians ,I believe it's the autonomic nerves type that comes with anaemia . And a bit numbness in fingers, I don't know what constitutes neurological symptoms other than these, ? Usual memory loss, foggy brain, feeling sometimes like falling over, feeling unsafe to drive due to lack of concentration. Are these sygnificant? I'm finding it hard to accept and come to terms with the fact that PA is so misunderstood and under treated. My Gp is doing the obligatory thyroid .ige,foliage bloods right now, and will refer me to Heamatology is its blank .

His attitude was don't know it will do any good, as I'm on the nhs set treatment. And my blood has always had misshapen cells it's just me apparently. I feel I have a fight on my hands. Any more help Welcome. Thanks all.


Hi Bobonut., your GP thinks you're on the NHS 'set' treatment? Well, not if you have neurological symptoms. And you do!

Your GP can look this treatment up. It's in the British National Formulary. This will be on his desk. It's the second item down so he will have to read further than he usually does. I must say that he is, unfortunately, not alone in being apparently unaware of this neurological treatment protocol - most GP's have no knowledge of this!

Sleepybunny has already outlined what the. Euro,official regime is, so I won't repeat them again...but these are what you should be getting 😀!

I note that your GP is doing thyroid tests. Good - but I hope he's doing a full thyroid screen and not just TSH levels (I understand from folks here who belong to thyroid UK that the TSH test alone does not give a full picture and is as unreliable as the serum B12 test).

And I second fbirders advice about the folate, so good that that's also being done.

Interestingly, I looked on the Guys and St Thomas' website at the referral requirements for the haematology department and it states that where B12 deficiency treatment has taken place and macrocytosis is present with neurological symptoms, then an urgent referral should be made. However, what I don't know is if your long standing problem with macrocytosis negates this. But I would be concerned about the neurological symptoms.

If I get this right, you were doing okay but have started to struggle more recently? Just wondering why this may be...can you identify anything that has changed. Perhaps it may be a 'simple' as low folate levels - here's hoping 😀.

If your neurological symptoms don't improve, then it would be beneficial to see a neurologist so that any other potential causes can be ruled out. Its all too easy to put everything down to B12 deficiency and there have been several stories here recently about members who have had other conditions diagnosed on referral. But I'm certainly not saying that you h e over conditions 😀.

Everybody here will spypathise with your struggles and share your frustration at the lack of knowledge most medic's seem to have (or have not!) when it comes to B12 deficiency and PA. getting proper treatment can be a nightmare and as for care...well!

Please do,post again and let us know how you get on and remember, there are lots of people here, ready to help, if needed.

Good luck and take care xx


Thank you foggy me, a lot to think of. To be honest though I only did well the first 6 months on b12 so slowly over the last few years it's been a drip effect on symptoms around the next jab. I became ill if I missed one but now I'm ill before it's due. I'll post more next week when I have the blood results. I think it's just TSh levels though.


Ha...I think you need the neurological regime 😀.

Good luck with the blood results...will watch out for your post xx


suggest also do "Magnesium RBC" test.


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