Another very important function of the spleen is creation of
blood cells. In cases where the bone
marrow is producing fewer blood cells than normal (like myelofibrosis), the
spleen can actually compensate to produce red and white blood cells. About ¼ of the body’s white cells are stored
in the spleen at any time.
Swelling of the spleen is called splenomegaly. If a swollen spleen can be felt manually, it
is at least twice its normal size. The spleen
usually swells when it is working harder than normal. This can happen for several reasons.
Swelling of the spleen often has no symptoms. It can cause abdominal, chest or back pain
and the feeling of having a “small stomach,” being able to eat less than normal
in one sitting. Anemia may also be
present. The most common reason is
developed countries is mononucleosis, followed by infiltration by benign or
neoplastic cells, or portal hypertension.
Bacterial infections like syphilis can also cause a swollen spleen. In people whose bone marrow is not producing
enough cells, the spleen can become swollen by the effort of producing extra
cells.
It is should be stated that swelling of the spleen is pretty
common in blood disorders. It is
sometimes found in systemic mastocytosis.
As the spleen gets bigger, it grows beyond the borders of the protective
rib cage and can be more easily damaged.
Swollen spleens present an increased risk of rupture.
In SM, splenomegaly (swollen spleen) is NOT a C finding
indicating aggressive disease. It is a B
finding. This is because mast cells
often infiltrate the spleen, causing swelling, but not necessarily impairing
function. Hypersplenism with
splenomegaly is a C finding.
Hypersplenism is when the spleen is working too hard.
Hypersplenism is indicated by swelling of the spleen, reduction
in circulating red blood cells, platelets or granulocytes (neutrophils,
eosinophils, basophils or mast cells), increased proliferation by the bone
marrow to compensate for the decrease in circulating cells, and probable
resolution of these symptoms by removal of the spleen. Hypersplenism
can cause additional complications, including portal hypertension and ascites.
Portal hypertension is increased pressure in the vein that
connects the GI tract and spleen to the liver.
Ascites is free fluid in the abdomen.
Both portal hypertension and ascites are also mastocytosis C findings. Removal of the spleen can decrease the
patient’s risk of portal hypertension and ascites, thus improving
prognosis. Additionally, in the context
of mast cell disease, an infiltrated organ is inflamed, which is in turn
activating to mast cells. Removal of a
source of inflammation can cause relief of systemic activation.
People living without a spleen are more susceptible to
certain types of infections, including H. influenzae, S. pneumoniae, and
Meningococcus spp. They should receive
vaccinations for these organisms and also regular flu vaccinations. In some cases, long term prophylactic
antibiotics are needed. Often, patients
without a spleen develop a stable high white blood cell or platelet count as
their numbers are not regulated by the spleen.
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