Pernicious Anaemia is perhaps the first recognised condition caused by, and causing, vitamin B₁₂ deficiency.

Pernicious anaemia (PA, also known as Addison’s anemia, Biermer’s anemia, Addison-Biermer’s anemia, etc) is an autoimmune disease (see also Multiple Sclerosis) in which the sufferer cannot absorb much Vitamin B₁₂ from the diet. See more on pernicious anaemia including history of the disease <here>:

Symptoms are the symptoms of vitamin B₁₂ deficiency:

Since PA results in failure to absorb B₁₂, symptoms of B₁₂ deficiency will result.

• extreme fatigue, especially characterised by deep sighing breaths, feeling tired when you wake in the morning and unable to function in the afternoon, unable to sleep at night
•  loss of feeling (numbness, pins and needles, chronic pain) especially in limbs.  It often starts in the feet and lower legs, and moves to hands and arms.
•  loss of muscle control (paralysis of a single limb, spasms and jerky movements, difficulty swallowing or speaking, difficulty seeing)
• confusion (‘the fogs’), dementia, memory loss
• emotional and depressed (low) mood
• red, sore tongue and mouth
• weight loss
•  diarrhoea
• difficulties walking (for example, ataxia)

Case study – Frankie

Frankie explains how difficult it is to pin down the symptoms – she describes a variety of seemingly unconnected symptoms of vitamin B₁₂ deficiency, which could so easily be put down to something else.

Frankie’s main complaint is her digestive problems.  She feels bloated, feels full, can’t help belching and burping.  Of course she has tried changing her diet.  But she notices that as soon as she’s had her vitamin B₁₂ injection, all those stomach problems ease off and she’s back to normal (without changing diet!).

She also pointed out loss of hair, tiredness, headaches – all familiar symptoms but all symptoms that could so easily be blamed on something else. Her first sign that she’s due for her next injection is a bad headache.  Luckily, her GP diagnosed Pernicious anaemia on the basis that she has no Intrinsic Factor (needed to absorb B₁₂) and the GP provides B₁₂ replacement therapy by injection.

Frankie thinks it came from her grandmother, who died in a home for the insane having never recognised her granddaughter.  The ‘insanity’ could have been early Alzheimers’, which suggests Frankie has inherited her PA.

Diagnosis of Pernicious Anaemia

(Figure 2)  Since it is a failure to absorb due to damage to the lining of the stomach, Pernicious anaemia can be diagnosed with a number of tests including

·         the presence of macrocytes (megablasts, or immature oversized red blood corpuscules that don’t carry oxygen properly – which is why you get so tired),

·         presence of Intrinsic Factor antibodies (IF Ab) (the Intrinsic Factor is produced in your stomach to bind to B₁₂ and transport it into the blood stream for distribution around the body – IF antibodies or parietal cell antibodies are a sign that your immune system is killing off the stomach cells and mean you don’t have IF) and

·         blood serum B₁₂ below a set threshold, which unfortunately varies from country to country.

·         The Schilling test used to be used to measure a person’s ability to absorb radioactive B₁₂, but it is difficult and expensive.

PA is fatal within 3 years unless treated with B₁₂ replacement therapy.  It is likely to be widely under-diagnosed[1] because folate (Vitamin B9) is added to many foods and folate masks the impact of vitamin B₁₂ deficiency on red blood cells, and as symptoms of vitamin B₁₂ deficiency are similar to other diseases this can mean a diagnosis isn’t given.  PA is where a person is not able to absorb B₁₂ because they lack Intrinsic Factor, and there are a number of other causes for B₁₂ deficiency; PA may also be one of the outcomes of B₁₂ deficiency but other outcomes such as severe neuropathy (often resulting in muscle wastage, pain, paralysis, loss of feeling) may occur without anaemia.  PA is one cause of B₁₂ deficiency: other causes can include

• lack of B₁₂ in the diet (eg vegans, vegetarians. B₁₂ is produced by bacteria in the gut of say a ruminant (cow, sheep, goat) and is not produced by any animal) or competition (tapeworm, some tropical diseases)
• stomach or intestine surgery leaving too little stomach wall to produce enough IF, or too little intestine to absorb the B₁₂/IF complex.  After any GI surgery B₁₂ should be given IM or SC (as an injection) routinely
• inability to transport B₁₂ (a number of genetic abnormalities affect the Transcobalamin family, in particular TC-II which transports B₁₂ in the blood, which can either make the B₁₂ in the blood unavailable to body tissues, or mean it fails to get into the tissues)
• inability to use B₁₂ in spite of high B₁₂ in the blood (so-called ‘Subtle’ B₁₂ deficiency)

Treatment

PA is typically treated with intramuscular or subcutaneous injections of vitamin B₁₂ as hydroxyl-cobalamin or methyl-cobalamin (we used to use cyano-cobalamin as well), or megadoses (eg 1000µg/day) of Vitamin B₁₂ orally as sublingual lozenges or tablets (if you are able to absorb from very high doses).

Links

Pernicious Anaemia Society UK – http://www.pernicious-anaemia.org.uk

Wikipedia article on Pernicious Anaemia – http://en.wikipedia.org/wiki/Pernicious_anemia

NetDoctor article – http://www.netdoctor.co.uk/diseases/facts/anaemiab12.htm

Citations

1.            McBride, J. B12 Deficiency May Be More Widespread Than Thought. Agricultural Research Service  2000 2 Aug [cited 2009 2 Oct]; Available from: http://www.ars.usda.gov/is/pr/2000/000802.htm.