Here we’ll take a look at leukemia.
It’s a topic that most med students are quite afraid of.
But not to worry.
We will go through this together.
And by the time we’re done, your thoughts will be extremely organized
and you’ll be able to identify your patient very, very confidently.
Let’s take a look.
What does acute mean to you?
It means fast.
What does leukemia mean to you?
It means cancer.
A cancer developing from where?
That’s where your focus will be initially.
However at some point in time, you do know that
on your peripheral blood smear you are then going to find an increased number of cells.
That puts this into leukemia.
And there is every possibility with the leukemia that
these cells might then enter a lymph node.
And therefore the presentation here might be very much like a lymphoma
and that will tell you as to when that will be relevant to you
for symptoms and signs as far as the patient is concerned.
Is it neoplastic leukocytic origin?
If you found predominance of immature cells, which are then called blasts,
Bone, bone, bone, bone, bone marrow.
B as in blasts.
B in bone marrow.
What is acute?
What does this mean?
Since this is a leukocytic type of neoplasm
that the cell within the bone marrow is not being matured quick enough.
In fact, many of your cells of the neoplasm remain in its blastic form,
which is a very primitive and very young cell.
ALL or AML which are both acute leukemias,
by definition, you have to find greater than 20% blasts in the bone marrow.
Once that’s understood, it’s only then we can move on.
The symptoms in acute leukemia are due to bone marrow failure.
This results in decreased production of normal blood cells leading to anemia, thrombocytopenia and leukopenia.
I would like to point out that although the white blood cell count is high, these cells represent the immature, circulating blasts.
So even though there is an increase in the number of circulating leukocytes,
there is functional leukopenia because these cells do not function properly.
Usually the first symptom that the patient is exhibiting
would be signs and symptoms of anemia.
Meaning to say fatigue and tiredness.
The one that you’re worried about very much in terms of pancytopenia
would be the susceptibility to infections,
Definition of acute leukemias referring to both AML or ALL,
greater than 20% blasts in the bone marrow.
Etiology, chromosomal abnormalities are a possibility
and Down syndrome is something we’ll take a look at.
We’ll take a look at ALL, ionizing radiation.
We have chemical exposure or maybe even perhaps alkylating agent.
Wait, hold down for a second.
You should be asking yourself what does this mean?
The patient was receiving chemotherapy for another type of cancer.
And while receiving the chemotherapy unfortunately develops another type of leukemia.
So even alkylating agents that are being used to prior cancers
might then unfortunately give rise to a new leukemias.
There will AML/ALL.
Next, what you want to do with acute leukemias?
So far, you have a definition of leukemias.
This is a neoplasm of your leukocytic origin from the bone marrow.
We have greater than 20% blasts from the bone marrow.
And now, we’ll take a look at the various lineages of your cell or your bone marrow,
the 2 major lineages.
One lineage will be myeloid.
The other lineage will be lymphoid.
If you’re thinking myeloid, it’s all cells
except your T-cells, B-cells and natural killer cells.
So when you say acute myelogenous leukemia,
you know that you’re dealing with many different types of myeloid cells.
Hence, you will be using what’s known as FAB classification,
M0 all way out to M7.
By the time we come to M3 you’ve heard of,
well, this is promyelocyte.
Hence, M3, which we will be focusing upon,
is called your acute promyelocytic leukemia or promyelocytic leukemia.
Do not forget the other name.
By the time you’re still getting to M5, you’re producing more monocytic.
By the time you’re still getting to M5 to M6 and such,
more RBC’s and M7 will be megakaryocytes.
All myeloid, all myeloid.
Disease of immature granulocytes.
Seen in, well basically, all age ranges.
Look at this, 15-60,
so the age is not going to tell you much.
Tell me what you’re going to find in your bone marrow?
Greater than 20% blasts in your bone marrow.
And if you’re thinking myeloid,
you’re affecting all the myeloid cells except T-cells and B-cells.
What’s the other type of acute leukemia?
It’s acute lymphoblastic leukemia, would be the better name that you need to know.
Once again why do we call this lymphoblastic?
Because you will find greater than 20% blasts in the bone marrow.
Since we’re dealing with ALL, lympho-.
There’s only 2 types of ALL,
T type and B type,
B type/T type, T type/B type.
If it’s AML, there is 7 different subtypes
because there are 7 different methods of developing other myeloid cells.
Disease of immature lymphocyte, pre-B or pre-T ALLs.
Typically, now you know that this is the youngest leukemia causing cancer.
So in this, you’re thinking about age group of, well, less than 15 years of age.
Number 1 leukemia in this age group.