Pernicious Anaemia Society
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Dementia with b12 deficiency

Hi I've had b12 deficiency since February.

Well that's when I was diagnosed.

My main problem is my memory and tiredness .

I just can't remember anything at the moment and it's really scary.

Just typing this I have to check for mistakes all the time.

I'm injected with b12 once a month.

Have a great GP

I'm also very tired most of the time xx

Any advice please .

7 Replies

Perhaps you need more than one injection a month? My GP will only give me one every 3 months,so I inject once a week.and also make sure that I have plenty of folate(in my diet and with supplementation.) I have heard of people who inject daily to keep themselves well There is no danger involved,as B12 is a water-soluble vitamin,and any excess is eliminated in the urine.You could try asking your GP for extra injections, but he or she may not consent.You can always come to this site for advice on self-injection. I wish you all the very best.



I've assumed you're in the UK.

Did you have a series of loading injections when you were first diagnosed? Has your GP told you what he/she thinks caused the deficiency?

Do you have any neurological symptoms? The reason I'm asking is that the treatment for B12 deficiency with neurological symptoms is more intensive than b12 deficiency without neuro symptoms.

The treatment guidance for B12 deficiency can be found in the BNF (British National Formulary) Chapter 9 Section 1.2 and I think it's also in the "BCSH Cobalamin and Folate Guidelines". The BNF is copyrighted so can't reproduce the info here but this link contains similar info. Scroll down to Management.

Other useful info


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

"Pernicious Anaemia; The Forgotten disease" by Martyn Hooper

"Living with Pernicious Anaemia" by Martyn Hooper

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


pernicious-anaemia-society.... 01656 769467

The PAS are helpful to talk to and sympathetic. If you leave a message they will get back to you.


Have you had recent tests for ferritin, folate, B12 and a full blood count? I found it helpful to always get copies of my blood tests. There will probably be a charge for this.

I have read that patients need good levels of iron and folate for uptake of b12 to be good.

Are you on other drugs/medications? Some drugs can affect the uptake of B12.

Scroll down to "Drug induced causes"

Sadly illnesses can come in clusters. It is not unknown for B12 deficiency and PA (Pernicious Anaemia) to occur with thyroid problems/coeliac disease and other conditions.

If your GP has sanctioned injections every month then they are more enlightened than some GPs. Some people find they respond to a different form of B12. The NHS mainly uses hydroxycobalamin. There is also methylcobalamin, cyanocobalamin and adenosylcobalamin but these may not be available on the NHS.

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Have you had your iron and ferritin levels checked? That could contribute to tiredness. Seems to me that B12d efficient and iron deficiency seem to happen together. That was the case with me. Good luck!

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Ideally, as Sleepy Bunny has said, you should have had treatment according to the BNF in the BCSH guidelines:

"The BNF advises that patients presenting with neurological symptoms should receive 1000 ug i.m. on alternate days until there is no further improvement".

My sister was misdiagnosed with ME for years and then dementia. It turned out to be B12 deficiency and she made a good recovery on monthly injections of B12 but still finds this is not frequent enough, so supplements with Jarrows Methylcobalamin 5000 mcg sublingually (good reviews on Amazon for neurological symptoms) - Sally Pacholok recommends covering all bases.

Hopefully, as you have a good GP, he will support you in providing more frequent injections. It might help to take someone with you to stress your concerns and write down a list of history, ongoing symptoms, etc. Very best wishes for a good outcome.

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Hi there, my 81 year old mum had been misdiagnosed with vascular dementia. She was severely unwell - unable to talk. It's been 6 weeks and she's making good progress but still miles to go.

How long did it take for your sister to recover?



I'm so glad you and your mum are making good progress. My sister made a remarkable recovery of physical symptoms after injections were finally begun. Unfortunately, her surgery was uncooperative, delayed and failed to provide sufficient treatment before finally stopping injections altogether, as well as reducing thyroid medication! They insisted that 'she had more than enough B12 in her blood' and refused to refer to guidelines or research.

Her memory and neurological symptoms became worse and she quickly went downhill in spite of self injection. They also finally diagnosed vascular dementia, but I believe this is just another misdiagnosis.

Once memory fails, it is very difficult to monitor essential medications, which is why it's so important to treat aggressively within the short window of opportunity before permanent neurological damage sets in.

This Dutch link may be helpful:

"After a year :

The need for quick and correct treatment is emphasised further by the fact that after a year of treatment only 4 % of patients are fully recovered. Fortunately half of the patients have experienced a lot of improvement in their symptoms after a year of treatment but there are still a lot of patients with remaining symptoms, who could possibly have recovered if their treatment was started promptly and adequately. We will pay more attention to this aspect in a following survey.

More than a year after the start of the treatment 25.7 % still suffer from serious to very serious fatigue. About 15 % still experience nerve pain and/or muscle pain and weakness.

Other symptoms that remain troublesome are concentration problems, memory problems, word finding problems and intestinal complaints. 60 % of the patients feel that they are receiving sufficient treatment."

You are doing a great job in looking after your mum's health and I hope things continue to improve for you both. Very best wishes RDB1.


Do you know what form of B12 you are being treated with

Different countries tend to use different forms (eg cyano tends to be used in US, hydroxo in UK and most of europe). People can respond differently to different formats - there is currently no way of predicting to start with which format you will respond best to. There are also methylated forms of B12 - methyl and adenosyl (which has other names as well) and some people respond better to these - but not everyone. They tend not to be generally used because they aren't as stable as cyano and hydroxo.

Some people just need more frequent B12 - measuring how much B12 is in the blood can help identify if there is a problem (ie levels may fall very quickly in some people) but in some people the probelms exist even if levels in blood are high.

Also possible - as hinted by others - that there is more than B12 going on.


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