supplementation to stimulate the remaining red
bone marrow to increase its erythrocyte production
(erythropoiesis). Occasionally CHEMOTHERAPY and
RADIATION THERAPYto suppress bone marrow func-
tion, curtailing proliferation of the defective stem
cells, slows the condition’s progression. BONE MAR-
ROW TRANSPLANTATIONis sometimes a viable option.
The outlook for myelofibrosis is variable; treatment
is not curative and ultimately the bone marrow fails
completely. Occasionally myelofibrosis evolves into
acute myeloid LEUKEMIA, a rapidly progressive type
of cancer in which blast cells (immature leuko-
cytes) take over the bone marrow.
See also POLYCYTHEMIA VERA; THROMBOCYTHEMIA;
THROMBOCYTOPENIA.
neutropeniaLower than normal numbers of neu-
trophils circulating in the BLOOD. Neutrophils are
the most abundant of the three subtypes of granu-
locytes; the GRANULOCYTE is a type of LEUKOCYTE
(white blood cell). Neutropenia, which can be
acute or chronic, results in increased susceptibility
to bacterial and fungal (yeast) INFECTION. Severe
neutropenia can leave the body virtually defense-
less against such infection, as neutrophils are the
front line of response to invading pathogenic
microorganisms.
The causes of neutropenia are numerous.
Among the most common are
- acute viral infections such as mononucleosis,
CYTOMEGALOVIRUS(CMV), INFLUENZA, HIV/AIDS, and
HEPATITIS - AUTOIMMUNE DISORDERS
- cancers of the BONE MARROWsuch as LEUKEMIA
andMULTIPLE MYELOMA - LYMPHOMA
- Vitamin B 12 deficiency
- long-term, chronic ALCOHOLconsumption
- RADIATION THERAPYandCHEMOTHERAPY
- adverse DRUG reactions, notably with NONS-
TEROIDAL ANTI-INFLAMMATORY DRUGS(NSAIDS) and
penicillin ANTIBIOTIC MEDICATIONS
Chronic neutropenia is common with chronic
infections such as HIV/AIDSand with AUTOIMMUNE
DISORDERS. The primary symptoms of neutropenia
are typically those of the infection that is present.
Diagnostic blood tests that show lowered numbers
of neutropenia in the blood confirm the diagnosis.
Treatment targets the underlying health condition
or removes the offending medication. In many
people neutropenia is transient and self-limiting.
See also LEUKOPENIA; LYMPHOCYTOPENIA; MONONU-
CLEOSIS; INFECTIONS; THROMBOCYTOPENIA.neutrophil See GRANULOCYTE.neutrophil 161