Pay Attention To Medical Myths!

(A bouncing ball captured with a stroboscopic flash at 25 images per second: Source)

Hola Amigos!

It indeed has been a very long time since my last entry. This time around, let’s focus on something different. I’d like to talk about medical myths and how they might wreak havoc in your lives. No, I don’t mean the food fads, the herbal remedies your grandma made popular and all that. This article’s meant for the doc in training.

Consider this question:-

What antibody response is typical of Extrinsic Allergic Alveolitis?

In case you hadn’t read about this disorder’s immunology specifically, your survival instincts would have immediately led you to say IgE. Given the utterly memory-oriented way our brain functions in modern medical study, it immediately homes onto specific keywords in the question. Allergy and IgE go hand in hand don’t they? Well, not in this case they don’t. The correct answer here happens to be IgG.¹ Examinations such as the USMLE will test you with these odd-balls and boy do they constitute a bunch! Regardless of the ethical issues concerning what should or shouldn’t be tested in medical examinations, knowing the right responses to such questions and indexing them to one’s already burdened memory can indeed make or break one’s career.

There’s another oddity that you’d be interested to know about Extrinsic Allergic Alveolitis. This is one lung disorder that has a lower incidence rate among smokers!²

That’s it for now. Hope you’ve found this post interesting. Your comments are welcome as always. Until my next post, Ciao!

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References:-

1. Current Pulmonary, Chapter 32. Hypersensitivity Pneumonitis, Clinical Findings; by Cecile Rose MD MPH
2. Current Pulmonary, Chapter 32. Hypersensitivity Pneumonitis, Pathogenesis; by Cecile Rose MD MPH

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“Millions saw the apple fall, but Newton was the one who ASKED WHY.”
~ Bernard Mannes Baruch
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Copyright © 2006 – 2008 Firas MR. All rights reserved.

HLA-haplotypes and the Blood Transfusion vs. Bone Marrow/Organ Transplantation paradox

Source

Explain the following dichotomy &/or paradox :-

Q. Why is it that while blood donations between family members (in other words, those individuals who share HLA-haplotypes) are discouraged, bone-marrow/organ transplantations are encouraged between them?

Background keywords :-

• blood (a type of connective tissue) – blood relative – HLA haplotype sharing – donor lymphocyte attack on host cells – transfusion associated graft versus host disease (TAGVHD) – blood donation from family donors contraindicated unless products irradiated
• organ donation – allogeneic bone marrow transplantation – closely matched HLA donor – family donor – host versus graft reaction or graft rejection – acute & chronic graft versus host disease (GVHD) – leukemias – graft versus leukemia effect – donor lymphocyte infusion – reduced intensity bone marrow transplantation

Apparently, GVHD is not so much of a problem in bone-marrow/organ transplantation when compared to blood transfusion. In fact, the graft versus leukemia effect (a type of GVHD), coupled with donor lymphocyte infusion, is used to our advantage in ‘reduced intensity bone marrow transplantation’ for the treatment of leukemias. Why the difference?

Background books:-

• Davidson’s Principles & Practice of Medicine 20 ed
  • Part 2 PRACTICE OF MEDICINE > 24 Blood disorders > BLOOD PRODUCTS AND TRANSFUSION > ADVERSE EFFECTS OF TRANSFUSION
  • Part 2 PRACTICE OF MEDICINE > 24 Blood disorders > HAEMATOLOGICAL MALIGNANCIES > LEUKAEMIAS
• Harrison’s Principles of Internal Medicine 16 ed

——
“Millions saw the apple fall, but Newton was the one who ASKED WHY.”
~ Bernard Mannes Baruch
–

Copyright © Firas MR. All rights reserved.