The subject of Medicine is insanely vast, how does one remember everything? Here’s one clue – remembering mechanisms of causes is easier than remembering the causes themselves, which can then be derived via logic & experience. Having a logical structure to remember pathologies & differentials in medicine is no different than logically arranging books by subject in a closet. This post shows you how I encode the semantics of anemia causes in my brain for easier recall . Then it’s just a matter of analysis and time figuring out what fits the context of a given patient.
The main two causes of anemia are Excess Loss (via Bleed or Hemolysis ) and Reduced Production. ( and there is a minor effect of fluid Dilution ) . If the cause isn’t evident initially, a useful lab to give you a clue about the Loss v/s Production issue is the Reticulocyte Production Index, which rises in blood loss. Let’s look at how to remember causes of anemia easily with a little more logical detail :
🩸 DEPLETION: aka Bleeds [Internal (e.g Hemothorax) v/s External ( e.g GI bleed ) ] – includes chronic blood loss (e.g worms, frequent blood draw for labs, oozing portal hypertensive gastropathy etc)
🩸 DESTRUCTION: aka Hemolysis [Intrinsic to RBC (e.g. Sickle Cell, G6PD, Sideroblastic) v/s Extrinsic (e.g. Autoimmune, Transfusion)]
🩸 DECREASED PRODUCTION which includes:
–Depressed Marrow: e.g Aplastic, Chemo, Alcohol, etc
–Deficient Marrow: Deficiency of raw material [ e.g Iron / B12 / Folate / Erythropoietin deficiency]
(I include Anemia of chronic disease here since Hepcidin limits the amount of iron available to blood formation in a state of chronic inflammation)
–Destroyed Marrow: Includes MDS and Myeloproliferative disorders, infiltration by other tumors like Multiple Myeloma, Bony metastasis, etc
🩸 DILUTION: IV fluids, Edema from CHF, Cirrhosis etc
p.s: 1. Anemia types can frequently overlap, so a patient may have more than one cause with additive effects. Example: A patient with leukemia with chemotherapy-induced pancytopenia admitted with neutropenic sepsis and infused with IV fluids, intubated after pulmonary edema then develops stress ulcer bleeds – how many causes of anemia do you see?
2. Notice how the above categories start with a ‘D’ – that’s to make it easier to recall!
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