Pernicious Anemia
Author/s: Rosalyn S.
Carson-DeWitt<br
blood cells
are abnormally formed, due to an inability to absorb
vitamin B12. True pernicious anemia refers specifically
to a disorder of atrophied parietal cells leading to
absent intrinsic factor, resulting in an inability to
absorb B12.<br
plays an important role in the development of red blood
cells. It is found in significant quantities in liver,
meats, milk and milk products, and legumes. During the
course of the digestion of foods containing B12, the B12
becomes attached to a substance called intrinsic factor.
Intrinsic factor is produced by parietal cells which line
the stomach. The B12-intrinsic factor complex then
enters the intestine, where the vitamin is absorbed into
the bloodstream. In fact, B12 can only be absorbed
when it is attached to intrinsic factor.<br
pernicious anemia, the parietal cells stop producing
intrinsic factor. The intestine is then completely unable
to absorb B12. So, the vitamin passes out of the
body as waste. Although the body has significant
amounts of stored B12, this will eventually be used up.
At this point, the symptoms of pernicious anemia
will develop.<br
among people from northern Europe and among African
Americans. It is far less frequently seen among people from
southern Europe and Asia. Pernicious anemia occurs in
equal numbers in both men and women. Most patients with
pernicious anemia are older, usually over 60. Occasionally,
a child will have an inherited condition which
results in defective intrinsic factor. Pernicious anemia
seems to run in families, so that anyone with a
relative suffering from the disease has a greater
likelihood of developing it as well.<br
symptoms<br
the stomach called parietal cells. When these
parietal cells shrink in size (atrophy), they produce less
and less intrinsic factor. Eventually, the parietal
cells stop functioning altogether. Other important
products of parietal cells are also lessened, including
stomach acid, and an enzyme involved in the digestion of
proteins.<br
chance of having certain other conditions. These
conditions include autoimmune disorders, particularly those
affecting the thyroid, parathyroid, and adrenals. It is
thought that the immune system, already out of control in
these diseases, incorrectly becomes directed against
the parietal cells. Ultimately, the parietal cells
seem to be destroyed by the actions of the immune
system.<br
to a disorder of atrophied parietal cells leading to
absent intrinsic factor, resulting in an inability to
absorb B12. However, there are other related conditions
which result in decreased absorption of B12. These
conditions cause the same types of symptoms as true
pernicious anemia. Other conditions which interfere with
either the production of intrinsic factor, or the body’s
use of B12, include conditions that require surgical
removal of the stomach, or poisonings with corrosive
substances which destroy the lining of the stomach. Certain
structural defects of the intestinal system can result in an
overgrowth of normal bacteria. These bacteria then absorb
B12 themselves, for use in their own growth.
Intestinal worms (especially one called fish tapeworm) may
also use B12, resulting in anemia. Various conditions
that affect the first part of the intestine (the
ileum), from which B12 is absorbed, can also cause anemia
due to B12 deficiency. These ilium related disorders
include tropical sprue, Whipple’s disease, Crohn’s
disease, tuberculosis, and the Zollinger-Ellison syndrome.
July 8th, 2006 at 10:36 pm
Symptoms of pernicious anemia and decreased B12
affect three systems of the body: the system that is
involved in the formation of blood cells (hematopoietic
system); the gastrointestinal system; and the nervous
system.<br
required for the proper formation of red blood cells.
Without B12, red blood cell production is greatly
reduced. Those red blood cells that are produced are
abnormally large and defective in shape. Because red blood
cells are responsible for carrying oxygen around the
body, decreased numbers (termed anemia) result in a
number of symptoms, including fatigue, dizziness,
ringing in the ears, pale or yellowish skin, fast heart
rate, enlarged heart with an abnormal heart sound
(murmur) evident on examination, and chest
pain.<br
sore and brightly red tongue, loss of appetite, weight
loss, diarrhea, and abdominal cramping.<br
system is severely affected when pernicious anemia goes
untreated. Symptoms include numbness, tingling, or burning
in the arms, legs, hands, and feet; muscle weakness;
difficulty and loss of balance while walking; changes in
reflexes; irritability, confusion, and
depression.<br
blood
test reveals abnormally large red blood cells. Many of
these will also be abnormally shaped. The earliest,
least mature forms of red blood cells (reticulocytes)
also will be low in number. White blood cells and
platelets may also be decreased in number. Measurements of
the quantity of B12 circulating in the bloodstream
will be low.<br
will be important to diagnose the cause of the anemia.
True pernicious anemia means that the parietal cells
of the stomach are atrophied, resulting in decreased
production of intrinsic factor. This diagnosis is made by
the Schilling test. In this test, a patient is given
radioactive B12 under two different sets of conditions: once
alone, and once attached to intrinsic factor. Normally,
large amounts of B12 are absorbed through the
intestine, then circulate through the blood, and enter the
kidneys, where a certain amount of B12 is then passed out
in the urine. When a patient has pernicious anemia,
the dose of B12 given by itself will not be absorbed
by the intestine, so it will not pass into the
urine. Therefore, levels of B12 in the urine will be
low. When the B12 is given along with intrinsic
factor, the intestine is able to absorb the vitamin.
Urine levels of B12 will thus be
higher.<br
administration
of lifelong injections of B12. Vitamin B12 given by
injection enters the bloodstream directly, and doesn’t
require intrinsic factor. At first, injections may need
to be given several times a week, in order to build
up adequate stores of the vitamin. After this, the
injections can be given on a monthly basis. Other substances
required for blood cell production may also need to be
given; they may include iron and vitamin C.
July 10th, 2006 at 12:11 am
Prognosis is generally good for patients with
pernicious anemia. Many of the symptoms improve within just
a few days of beginning treatment, although some of
the nervous system symptoms may take up to 18 months
to improve. Occasionally, when diagnosis and
treatment have been delayed for a long time, some of the
nervous system symptoms may be permanent.<br
increased risk of stomach cancer has been noted in patients
with pernicious anemia, careful monitoring is
necessary, even when all the symptoms of the original
disorder have improved.<br
Terms<br
responsible for oxygen delivery throughout the body (red
blood cells, hemoglobin) are decreased in quantity or
defective in some way. <br
shrinking in size of an organ or cell. <br
disorder<br
for fighting off such foreign invaders as bacteria
and viruses), begins to attack and damage a part of
the body as if it were foreign.
<br
responsible for the production of blood cells.
<br
cells of the stomach. In order to be absorbed by the
intestine, vitamin B must form a complex with intrinsic
factor. <br
line the inside of the stomach. These cells are
responsible for producing intrinsic factor, acid, and pepsin.
<br
time, the reticulocyte develops to become a mature,
oxygen-carrying red blood cell. <br
Your Information<br
and H. Franklin Bunn. “Megaloblastic Anemias.” In
Harrison’s Principles of Internal Medicine, edited by
Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.
<br
Williams’ Hematology, edited by E. Beutler, et al. New
York: McGraw-Hill, 1995.<br
Kelly. “Pernicious Anemia: How to Recognize and Manage
This Insidious Condition.” American Journal of Nursing
96, no. 11 (November 1996): 52+. <br
et al. “Pernicious Anemia.” The New England Journal
of Medicine 337, no. 20 (November 13, 1997):
52+.<br
1999.<br
information helpful.<br
and Health to you all. ~Taty
July 12th, 2006 at 3:23 am
Taty- what two good postings on pernicious anemia. It was good information for
all of us. <br
July 15th, 2006 at 8:09 am
Thank you for this information.<br
anemic for the last five years. The endo I was seeing at
the time thought it was due to my kidneys. Now seeing
a new Endo and he says my kidneys are fine. They
just checked out my digestive system for cancer and it
was fine. I had two polpys removed from my stomach
and one from my colon. Both pre cancerous. <br
am wondering with these test could they tell if my
partiel cells are damaged?<br