9A Flashcards
Causes of Basophilia and its threshold
It refers to an increase in the absolute basophil count above 200/mm3
The main causes of basophilia include:
1. Allergic reactions.
2. Cancers (MPD(s) including CML).
Causes of lymphocytosis
Acute bacterial infections (Whooping Cough that is associated with normal looking
lymphocytes and Brucellosis)
Chronic bacterial infections (Tuberculosis and Syphilis),
Parasitic infections (Malaria, and Toxoplasma),
Viral infections (Infectious Mononucleosis, Infectious Lymphocytosis, Measles,
Mumps, Rubella..)
Lymphoproliferative disorders (CLL).
How to diagnose lymphocytosis in all age groups
In adults,
absolute lymphocytosis is present when the absolute lymphocyte count is greater than 4000 per
microliter, in older children greater than 7000 per microliter and in infants greater than 9000 per
microliter.
What is commonly seen under staining a blood smear of a patient with lymphocytosis
The Smudge cells reflect the fragility of lymphocytes, which appear to be flattened or smudged in the process of being spread on the glass slide.
What are two special forces conditions where the lymphocyte count becomes very important
One of these occurs in children and is known as infectious lymphocytosis. So this is a
viral disease of children (1-10 years) in which the small lymphocytes increase very much
so that the count can become very high, yet all the lymphocytes appear normal.
Another viral infection is called infectious mononucleosis. The peripheral blood picture
of a patient with infectious mononucleosis contains a mixture of normal lymphocytes;
atypical .lymphocytes + an increased no. of monocytes with an increased WBC count
(12000-15000/ mm3)
Threshold and causes of monocytosis
Monocytosis is an increase in the number of monocytes circulating in the blood. It refers to an
increase in the absolute monocyte count 900/mm3.
Monocytosis often occurs during chronic inflammation. It is encountered in:
Tuberculosis and brucellosis.
Bacterial infections ( Subacute Bacterial Endocarditis)
Inflammatory diseases,
Parasitic infections,
Rickettsial diseases,
Fever of unknown origin,
Recovering phase of acute bacterial infections,
Infectious Mononucleosis
Various forms of malignancy (ex. leukemias (M4 and M5), preleukemic conditions such
as CMML.
What is eosinophilia? Discuss its causes and associated diseases
Eosinophilia:
Eosinophilia is a condition in which the eosinophil count in the peripheral blood exceeds
700/mm3. Several causes are known, with the most common being some form of allergic
reaction or parasitosis. In other words, the main causes of eosinophilia include parasitic
infestation (parasites that have a tissue cycle), allergic reactions e.g.: asthma, eczema, in
association with certain cancers or certain leukemias and in a certain disorder called
hypereosinophilic syndrome. This latter is a disease characterized by a persistently elevated
eosinophil count (≥ 1500 eosinophils/mm³) in the blood for at least six months without any
recognizable cause.
Causes of neutropenia
A-Decreased neutrophil production due to:
Aplastic anemia: Destruction or injury to the BM results in hypoplastic or aplastic
marrow with concomitant decreases in all cell types. Agents capable of causing marrow
suppression include: Ionizing radiation, chemicals such as benzene and a wide variety of
cytotoxic drugs used in the treatment of malignancy that destroy or interfere with the
mitosis of the proliferating cells. In addition, certain drugs can also affect the B.M. as
antimicrobials (chloramphenicol, sulfonamides), anticonvulsants, antithyroid drugs,
antihistamines, anti-inflammatory agents, antipsychotics, cardiovascular drugs …
Cancer particularly blood cancers: Marrow replacement by tumor, leukemic cells or by
fibrous tissue may also result in pancytopenia.
Vit B12 or folate deficiency: It causes pancytopenia because it affects all highly dividing
cells of the body including all blood elements.
Infections: Direct B.M suppression by toxins derived from the infectious agent.
B-Increased neutrophil destruction/utilization due to:
Infections: (Increased passage to the tissues or increased margination)
Any infection that overwhelms the marrow’s capacity to produce adequate numbers of
neutrophils will result in neutrophils being consumed or recruited to the tissues faster
than they are released by the marrow.
Immune reactions (isoimmune, autoimmune or drug induced)
1. Isoimmune or allo-immune neonatal neutropenia:
This is caused by a fetal – maternal incompatibility involving only the
neutrophils. It results from transplacental transfer of maternal IgG antibodies
directed against fetal neutrophils. In contrast to erythroblastosis fetalis, the first
born child is commonly affected.
2. Autoimmune neutropenia:
Autoimmune neutropenia is a form of neutropenia which is most common in
infants and young children where the body identifies the neutrophils as enemies
and makes antibody to destroy them. Acquired autoimmune neutropenia has been
described and is analogous to autoimmune hemolytic anemia but not as common.
3. Drug induced neutropenia:
Drug induced neutropenia is related to the use of a wide variety of drugs.
Sequestration by the spleen
A third mechanism for neutropenia is sequestration or trapping basically by the spleen.
Splenic enlargement, regardless of the cause, may lead to neutropenia, which is usually
relatively mild.
Treatment of neutropenia
Treatment consists of corticosteroids to reduce autoantibody production, antibiotics to
prevent infection and colony-stimulating factor such as G-CSF or GM-CSF to temporarily
increase neutrophil counts. In very severe cases, B.M transplantation may be the only
solution.
Threshold for neutropenia and neutrophilia?
ANC> 8000 /mm3
ANC< 1800 /mm3
Lymphocytosis in children vs elderly
Lymphocytosis is a feature of infection, particularly in children. In the elderly,
lymphoproliferative disorders, including chronic lymphocytic leukaemia and lymphomas, often
present with lymphadenopathy and a lymphocytosis.
