Erythrocyte destruction or deformity One of
the spleen’s roles is to filter erythrocytes from the
blood that are old or defective, a normal process
called HEMOLYSISthat maintains an appropriate bal-
ance of erythrocytes in the blood. The spleen may
inappropriately sequester and destroy healthy ery-
throcytes, sometimes without apparent reason.
SICKLE CELL DISEASEis a complex genetic disorder
that results in malformed erythrocytes, causing
anemia among other symptoms. In THALASSEMIA,
another genetic disorder, erythrocytes are normal
but hemoglobin is defective.
Inadequate erythropoiesis Nutritional deficien-
cies and renal failure are the leading causes of
diminished erythropoiesis. The bone marrow
requires vitamin B 12 , iron, and folic acid to manu-
facture erythrocytes. Pernicious anemia results
when the STOMACHfails to produce intrinsic factor,
a substance necessary to absorb vitamin B 12 from
ingested foods. When these vital NUTRIENTS are
lacking, the bone marrow cannot generate new
erythrocytes. Iron deficiency anemia is the most
common type of anemia in the United States.
Kidney disease and RENAL FAILUREalso affect
erythropoiesis because the KIDNEYS secrete ERY-
THROPOIETIN(EPO), the HORMONEthat stimulates the
bone marrow to produce erythrocytes. Bone mar-
row disorders such as myelofibrosis and MULTIPLE
MYELOMAalso disturb HEMATOPOIESIS. Aplastic ane-
mia is a life-threatening type of anemia that
results when the bone marrow completely shuts
down blood cell production.
COMMON CAUSES OF ANEMIAadverse DRUGreactions CHEMOTHERAPY
chronic HEPATITIS CIRRHOSIS
DYSMENORRHEA environmental toxins
folic acid deficiency GALLBLADDER DISEASE
GASTROINTESTINAL BLEEDING HEMOLYSIS
hemorrhage HIV/AIDS
INFLAMMATORY BOWEL DISEASE(IBD) iron deficiency
LEUKEMIA lymphoma
MALABSORPTIONsyndromes MULTIPLE MYELOMA
MYELODYSPLASIA SYNDROME MYELOFIBROSIS
PREGNANCY RADIATION THERAPY
RENAL FAILURE SICKLE CELL DISEASE
SYSTEMIC LUPUS ERYTHEMATOSUS(SLE) THALASSEMIA
vitamin B 12 deficiency
Symptoms and Diagnostic Path
Many people do not have symptoms of anemia
but instead find out they have anemia through
blood tests conducted for other reasons, such as
during ROUTINE MEDICAL EXAMINATIONor screening
for BLOOD DONATION. When symptoms are present,
they are generally the same regardless of the
underlying cause and commonly include- tiredness and fatigue
- breathlessness, especially with physical exercise
- HEADACHE
- chronically cold or tingling hands and feet
- PALPITATIONSor ARRHYTHMIA (irregular or rapid
heartbeat)
- irritability
- paleness of the SKIN, nail beds, and gums
Hemolytic anemia may also cause JAUNDICE.
Severe anemia can be debilitating, preventing an
individual from participating even in everyday
activities. Such severe anemias generally result
from serious underlying health circumstances.
Diagnostic blood tests including complete blood
count (CBC), hemoglobin, and hematocrit often
provide the initial diagnosis. Further tests might
include bone marrow biopsy to determine
whether the bone marrow is adequately produc-
ing erythrocytes or whether the erythrocytes are
normal. The doctor may choose to perform other
diagnostic procedures, depending on the findings.
Whether or not the anemia causes symptoms, it is
important to find its cause.Treatment Options and Outlook
Most types of anemia are curable or treatable.
Treatment targets the underlying cause of the ane-
mia. Supplemental iron, vitamin B 12 , and folic
acid can improve many types of anemia. Perni-
cious anemia requires lifetime injections of vita-
min B 12. Aplastic anemia or anemia due to
chronic health conditions may require BLOOD
TRANSFUSIONorBONE MARROW TRANSPLANTATION. Doc-
tors may treat chronic anemia or transient anemia
due to cancer treatment with EPO supplementa-
tion. Anemia resulting from GENETIC DISORDERS
such as sickle cell disease or thalassemia requires
ongoing treatment. Successful treatment of theanemia 125