can you have normal iron cells and no... - Pernicious Anaemi...

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can you have normal iron cells and not megablastic and still have pernicious anemia ?

2 years ago•7 Replies

I am curious to know if megablastic anemia whereby the bloodcells are larger in shape has to be present in PA patient. And my second question would be, wouldn’t one know at birth of the shape of their bloodcells were bigger than usual of different enough to suspect PA? Excuse my ignorance but I’m trying to understand

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Reembow

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Reembow2 years ago

please excuse the typos

palmier2 years ago

Red blood cells last about 100 days, so new ones form all the time. Their size and shape are affected by the nutritional status when they are formed. So they may turn out microcytic when someone is iron deficient and macrocytic when someone is b12 deficient. But it is also possible to be b12 deficient without having enlarged blood cells, because there are several factors that influence their size.

Gambit62Administrator2 years ago

macrocytosis is a symptom of B12 deficiency. It is not a defining characteristic.

PA is an autoimmune disorder of the gut, which attacks the mechanism used to absorb dietary B12 eventually leading to B12 deficiency.

The body has significant stores of B12 in the liver which it uses to regulate B12 levels in the blood. The release of this store relies on the same mechanism as you use to absorb dietary B12 so it becomes less and less efficient and that is when a B12 deficiency starts.

B12 is used in a lot of processes that go on in your cells with the result that a deficiency manifests in a lot of different ways. It is used in the process that produces red blood cells so macrocytosis is one of the symptoms but not necessarily among the first to develop. About 29% of patients with B12 deficiency do not present with macrocytosis. Some experts think it is acrually quite a late system to develop.

PA is not the only cause of B12 deficiency. It can also be caused by lack of B12 in the diet (eg vegans who do not supplement, and there are other absorption problems, such as H pylori infection, SIBO, crohns, coeliacs, drug interactions (eg metformin) and even tapeworm.

FlipperTD2 years ago

Scientist, not medic.

A treated PA patient won't have megaloblastic change in the bone marrow, so the red cells should be normal in size & shape. An untreated PA patient is likely to have macrocytosis, but if they have co-existing Iron Deficiency then it will be more confusing, and the iron deficiency results in smaller red cells, so you are likely to have somewhere inbetween.

You wouldn't know at birth for a variety of reasons, but we can start off with considering that PA is an acquired auto-immune condition, and is therefore highly unlikely to be present at birth. Neonatal haematology is another matter, as newborns [if my memory serves me well] have larger cells at birth, then their MCV falls, and eventually stabilises, but I'd need to check my textbooks to back this up. Newborns have 'different' haemoglobin, known as foetal haemoglobin [for obvious reasons] but that's another story entirely.

I hope this helps!