Leukopenia by Hussein Ali - PowerPoint Presentation

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Leukopenia

by

Hussein Ali

na

ji

Leukopenia

Leukopenia

refers to the decrease in the number of white blood cells (WBC) in blood. 

Causes of

Leukopenia

Leukopenia

may be caused by various diseases and drugs. Some of these are outlined here:-

A- Bone marrow damage or suppression

This is caused due to exposure to certain chemicals or toxins, cancer chemotherapy, radiation therapy and certain drugs. These agents cause a decrease in production of all the cells of the bone marrow leading to

leukopenia

, anemia (low number of red blood cell production and platelets).

B- Bone marrow diseases

In these conditions the bone marrow does not produce sufficient

WBCs

or selectively produces excess of one type of

WBCs

leading to a lack of other types. The causes include

myelodysplastic

syndrome, leukemia,

myeloproliferative

syndrome,

myelofibrosis

(bone marrow replaced by fibrous tissues), vitamin

B12

or

folate

deficiency etc.

C- Cancers that have spread to the bone marrow

Cancers when they have spread to the bone marrow may lead to

leukopenia

. This is seen in lymphomas and other cancers.

D- Autoimmune disorders

This occurs when the body fails to recognize its own cells and begins to attack them. In cases of

leukopenia

the body’s WBC’s are perceived as foreign and attacked. The condition is called lupus or Systemic lupus

erythematosus

(

SLE

).

E- Severe infections

Severe infections that deplete the body of

WBCs

may lead to

leukopenia

. This is called sepsis.

G

- Diseases of the immune system

Diseases of the immune system, such as HIV, which destroy T lymphocytes

H-

Hypersplenism

This is caused by enlargement of spleen that destroys the blood cells leading to

leukopenia

as well as anemia.

Pseudoleukopenia

This occurs at the initial phases of the infection. The leukocytes (predominately

neutrophils

) are responsible for the initial reaction to an infection. After an infection these cells gather around the margins of the blood vessels (marginalized) so that they can scan for the site of infection. Thus there is increased WBC production but it appears low from a blood sample, since the blood sample is of core blood and does not include the

WBCs

gathered to reach the site of infection.

Neutropenia

This term refers to an decreased numbers

neutrophiles

in blood circulation, under about 4× 10

9

in

monogastric

animals or about 1× 10

9

in ruminant, this can occur in a numbers way.

Viral infection. (e.g., parvovirus in dogs and cats and equine

herpesvirus

-1 in foals),

rickettsial

diseases

Increasd

demand for

neutrophils

without compensatory inflow from the bone marrow.

acute

salmonellosis

in horses and calves.

neutropenia

can occur following the net movement of

neu­trophils

from the

CNP

to the

MNP

, as occurs during shock.

Hypoplastic

condi­tions associated with

neutropenia

precursor cells in the marrow include idiosyncratic drug reac­tions (e.g.,

phenylbutazone

,

trimethoprim

/sulfadiazine,

gris­eofulvin

,

cephalosporins

,

fenbendazole

) estrogen toxicity (exogenous or endogenous) in dogs.

Increase destruction of

neutrophils

in circulation. This occur in autoimmune

neutropenia

.

Decreasd

bone marrow production.

Eosinopenia

This term refers to a decreased numbers

eosinopenia

in blood circulation, under about 0.1× 10

9

, The absolute

eosinophil

count may be zero in some normal animals, making

eosinopenia

of limited significance.

Endog­enous

&

exogenous

glucocorticoids

rapidly induce

eosino­penia

in animals due to the corticosteroid inhibit mast cells

regranulation

and so reduced histamine production and prolonged exposure to corticosteroids will reduce bone marrow

eosinophil

production.

Stress including prolonged intensive athletic training, acute stress causes increase catecholamine secretion and chronic stress causes increased corticosteroid secretion.

Lymphopenia

This term refers to an decrease numbers of circulating of lymphocyte, below about 1× 10

9

in

monogastric

animals or about 3× 10

9

in ruminant, this can occur in a numbers way.

Steroid effects. Any of reasons for increased circulating corticosteroid ( stress, steroid therapy)

Infection.

Lymphopenia

often accompanies the

neutropenia

seen in acute viral infections.

Neoplasia

.