What is the specific physiological mechanism that causes it it be so painful?
PIMF
“it it” = “it to”
The red blood cells (erythrocytes) that are damaged become stiffened and deformed. This causes them to rupture fairly easily and they can cause blockages in the smaller blood vessels.
Blockages = severely decreased blood flow to and from tissues = starved tissues + cellular waste build-up = exteme pain + breathing difficulties.
Much of the pain occurs because the sickled red blood cells clog up the small blood vessels and capillaries. This leads to a lack of blood downstream (“ischemia”) and that, in turn, causes the pain. Tissues with dense networks of capillaries are most likely to be affected in this way.
Sometimes the clogging is so severe that the tissues downstream actually die (infarction). This occurs especially in the spleen, kidneys, lungs, and around the hip joints.
The clogging effect is exacerbated by the tendency of the blood of “sicklers” to be deficient in nitric oxide (NO). Inadequate NO leads to constriction of blood vessels and thus further reduces blood flow.
The abnormal red blood cells of SS disease can form large masses by clumping together, and plug up the small blood vessels. This results in tissue becoming ischemic, and often dying. This process is very painful. Bone infarcts are common, which hurt a lot. Bone marrow dies too, and the spleen and kidneys can suffer small infarcts. Strokes also occur. Priapisms (painfully hard erections which won’t go down) occur, and may need surgical drainage to relieve them.
Nasty, nasty, nasty, nasty disease! Basically the sufferers can die bit by bit.
As a rule, anytime blood suppy to tissue is interrupted or destroyed we feel pain. The irregular sickle cells don’t flow smoothly through capillaries, clog or occlude them interrupting the blood flow to the tissues, causing tissue death and pain.
ischemia might be a good word to check in a dictionary.
Jois
No, no! You spelled it just fine, Jois!
LOL Thanks! It’s been quite a while!
Jois