Leukemia: Acute Leukemia – White Blood Cell Pathology

00:00 Here we’ll take a look at leukemia.

00:02 It’s a topic that most med students are quite afraid of.

00:05 But not to worry.

00:06 We will go through this together.

00:08 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.

00:14 Let’s take a look.

00:17 Acute.

00:18 What does acute mean to you? It means fast.

00:22 What does leukemia mean to you? It means cancer.

00:25 Okay.

00:26 A cancer developing from where? Bone marrow.

00:30 That’s where your focus will be initially.

00:33 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.

00:40 That puts this into leukemia.

00:42 And there is every possibility with the leukemia that these cells might then enter a lymph node.

00:47 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.

00:58 Is it neoplastic leukocytic origin? If you found predominance of immature cells, which are then called blasts, Where? Bone, bone, bone, bone, bone marrow.

01:10 B as in blasts.

01:12 B in bone marrow.

01:14 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.

01:25 In fact, many of your cells of the neoplasm remain in its blastic form, which is a very primitive and very young cell.

01:37 By definition, ALL or AML which are both acute leukemias, by definition, you have to find greater than 20% blasts in the bone marrow.

01:49 Once that’s understood, it’s only then we can move on.

01:54 The symptoms in acute leukemia are due to bone marrow failure.

01:58 This results in decreased production of normal blood cells leading to anemia, thrombocytopenia and leukopenia.

02:06 I would like to point out that although the white blood cell count is high, these cells represent the immature, circulating blasts.

02:14 So even though there is an increase in the number of circulating leukocytes, there is functional leukopenia because these cells do not function properly.

02:23 Usually the first symptom that the patient is exhibiting would be signs and symptoms of anemia.

02:30 Meaning to say fatigue and tiredness.

02:32 The one that you’re worried about very much in terms of pancytopenia would be the susceptibility to infections, leukopenia.

02:40 Definition of acute leukemias referring to both AML or ALL, greater than 20% blasts in the bone marrow.

02:48 Etiology, chromosomal abnormalities are a possibility and Down syndrome is something we’ll take a look at.

02:57 We’ll take a look at ALL, ionizing radiation.

03:00 We have chemical exposure or maybe even perhaps alkylating agent.

03:04 Wait, hold down for a second.

03:05 You should be asking yourself what does this mean? The patient was receiving chemotherapy for another type of cancer.

03:11 And while receiving the chemotherapy unfortunately develops another type of leukemia.

03:16 So even alkylating agents that are being used to prior cancers might then unfortunately give rise to a new leukemias.

03:24 Age.

03:25 Subtypes: There will AML/ALL.

03:31 Next, what you want to do with acute leukemias? So far, you have a definition of leukemias.

03:35 This is a neoplasm of your leukocytic origin from the bone marrow.

03:43 We have greater than 20% blasts from the bone marrow.

03:46 And now, we’ll take a look at the various lineages of your cell or your bone marrow, the 2 major lineages.

03:54 One lineage will be myeloid.

03:56 The other lineage will be lymphoid.

03:58 If you’re thinking myeloid, it’s all cells except your T-cells, B-cells and natural killer cells.

04:05 So when you say acute myelogenous leukemia, you know that you’re dealing with many different types of myeloid cells.

04:13 Hence, you will be using what’s known as FAB classification, M0 all way out to M7.

04:21 By the time we come to M3 you’ve heard of, well, this is promyelocyte.

04:26 Hence, M3, which we will be focusing upon, is called your acute promyelocytic leukemia or promyelocytic leukemia.

04:35 Do not forget the other name.

04:36 By the time you’re still getting to M5, you’re producing more monocytic.

04:40 By the time you’re still getting to M5 to M6 and such, more RBC’s and M7 will be megakaryocytes.

04:47 All myeloid, all myeloid.

04:49 Disease of immature granulocytes.

04:52 Seen in, well basically, all age ranges.

04:55 Look at this, 15-60, so the age is not going to tell you much.

05:00 Tell me what you’re going to find in your bone marrow? Greater than 20% blasts in your bone marrow.

05:06 And if you’re thinking myeloid, you’re affecting all the myeloid cells except T-cells and B-cells.

05:11 What’s the other type of acute leukemia? It’s acute lymphoblastic leukemia, would be the better name that you need to know.

05:17 Once again why do we call this lymphoblastic? Because you will find greater than 20% blasts in the bone marrow.

05:23 Since we’re dealing with ALL, lympho-.

05:27 There’s only 2 types of ALL, T type and B type, B type/T type, T type/B type.

05:34 If it’s AML, there is 7 different subtypes because there are 7 different methods of developing other myeloid cells.

05:41 Clear? Next.

05:43 Disease of immature lymphocyte, pre-B or pre-T ALLs.

05:47 Typically, now you know that this is the youngest leukemia causing cancer.

05:52 So in this, you’re thinking about age group of, well, less than 15 years of age.

05:57 Number 1 leukemia in this age group.