Investigations Done in Acute Leukaemia, Learn to Interpret Yourself

The investigations starts from the simplest and easiest test and thereafter more complex and precise investigations will be done. 

1.      Full blood count

This is the easiest, fastest and more feasible investigation done when acute leukaemia is suspected. So, if you have a full blood count report you may want to interpret it yourself. At a glance it may look a bit difficult, but once you have understood the symbols and their meanings, it will become easier. Once you learn to interpret one report, then you will be able to interpret and compare subsequent blood reports.

Let me take you through a full blood count report of a female patient with acute leukaemia. It will help you to understand your report clearly.   

		Normal Values
Total WBC	63×109 /L	4-11 ×109 /L
Neutrophils	02%
Lymphocytes	18%
Monocytes	0%
Eosinophils	0%
Basophils	0%
Haemoglobin (Hg)	10.4 g/dl	11.5-16.5g/dl
Red Blood Cells (RBC)	3.79×1012 /L	3.8-5.8×1012/L
MCV	82 fl	80-96 fl
PCV	31.1
MCH	23.735	27-32 pg
MCHC	33.5 g/dl	32-36 g/dl
Platelets	79×109	150-400×109/L

      Let’s discuss one by one. First let’s take WBC. WBC means white blood cells. As I have mentioned in my first post, there are several types of white blood cells. This is a patient with acute lymphocytic leukaemia. As you can see the number of white blood cells is way higher than the normal value. That is because the abnormally proliferated white blood cells are released in to the blood stream. One may think that white blood cells are involved in immunity and it is better to have a lot of white blood cells in the blood stream. But it is not because these extra cells are abnormal. They have had not got enough time to mature. So they don’t function normally. So, the excessive white blood cells do not help with immunity.

Next to WBC are shown the percentages of each type of white blood cells (Neutrophils, Lymphocytes, Monocytes, Eosinophils, and Basophils). By looking at this report we can only say that there is more than normal amount of white blood cells in the blood stream. To find out correctly the type of leukaemia, we should do a test called differential count (Blood Film). This test reveals the morphological types of the blood cells. In this patient it was found that there are blast cells in the blood stream. Blast cells are cells arising in the initial steps of the haemopeisis. This favors more towards the acute type of leukaemia. (In chronic leukaemia the predominant cells are more mature ones).

Also look at the haemoglobin level and the platelet number. They are also less than the normal amounts. It is because the proliferating cells have reduced the space available for the production of red blood cells and platelets.

2.      Bone marrow aspirate

Once the above abnormalities are found, a bone marrow aspirate is done to confirm and categorize the type of disease the patient have. This is a very painful procedure. The aspirate will be sent to the lab and the report will come with the following results.

a.      Increased cellularity

b.      Reduces erythropoeisis (the process of red blood cell production) – This is why there is less red blood cells in the blood stream.

c.       Reduced megakaryocytes – Platelets are produces by the megakaryocytes. This is why there is less number of platelets in the blood stream.  

d.      Replacement of blast cells.

3.      Chest X-ray – mediastinal widening. This is mainly done in T- lymphocytic leukaemia to see whether there is any enlargement of the thymus causing the mediastinum to grow wider.

4.      CSF (Cerebro-spinal Fluid) – This is done in acute lymphoblastic leukaemia, after blood is cleared from blast cells after therapy and to see whether there is any more in CSF.

                          

Before starting treatments the following investigations will be also done to assess the general condition of the patient.

1.      Biochemistry

a.      Serum urate

b.      Renal and liver biochemistry

2.      Cardiac function

a.      ECG

b.      Echo

c.       Cardiac MRI

 

 

References : Kumar P and Clark M, 2009. Clinical Medicine. 7th ed.

Diagnostic Process of Acute Leukaemia

How do doctors diagnose you as having Acute Leukaemia? In medicine diagnosis of a disease is done in three major steps. They are,

1.      History  

History is what the patient comes and complains to the doctor. Then the doctor gathers more information by asking questions from the patient. Most of the time a clinician can come to diagnosis only by the information he gather from the history. So, in history he will ask questions to see whether you have the symptoms of acute leukaemia that I have described in my previous post.

2.      Examination

Then he will examine you to find the signs of leukaemia. The things he will look for is described in my previous post.  

3.      Investigation

The investigation process involved in diagnosing acute leukaemia will be discussed in my next post.

What are the Features of Acute Leukaemias and Why do they Occur?

Even though there are several types of acute leukaemias, as I mentioned in my previous post, the clinical features of all these types are the same. Lets discuss each one of these features one by one and take a clear understanding about the mechanism of their occurrence.

1.      Anaemia

As now we know Leukaemia is abnormal proliferation of the blood forming cells. This process occurs in the bone marrow. As these cells proliferate and give rise to defective cells, the amount of normal cells reduces. Red blood cells are one such type of cell which reduces in number. So, the leukaemic patients present with anaemic features mentioned below.

a.      Exertional dyspnoea – The function of red blood cells is to carry oxygen to peripheral tissues. When we exercise the body requires more oxygen to produce energy to fuel the muscles which contract rapidly. When there are fewer amounts of red blood cells in the blood stream the muscle become lack of oxygen. So, they become exhausted as there is no enough fuel to keep them going.

b.      So, do you have exercise dyspnoea? Do you feel tired when climbing few steps? Do you become breathless even when walking several meters on a flat ground? If your answer to any of these questions is “Yes”, then yes, you have exertional dyspnoea.  

c.       Weakness – This is another symptom which indicates that you may be having anaemia. Do you feel weakness of your body even when you are resting? Do you feel like sleeping all the time? Do feel like your body doesn’t want to move an inch? If “yes” you are feeling weak.

d.      Pallor – So how do you know whether you are pale or not? To find pallor for a non medical person you may have to find someone who is healthy. Then you can compare yours with his/hers. Go in front of the mirror and pull down the lower eye lid and see the colour. Normal people’s colour is reddish pink. If the color is more close to white then you are pale, indicting that you have anaemia. Compare yours with that of someone healthy.

2.      Symptoms due to reduced white blood cells.

White blood cells are security guards of our body. They circulate in our blood stream and destroy any foreign agent (bacteria, viruses) that enters our body and protects our body from various diseases. In leukaemia the white cells are either reduced or defective. So the defective mechanism does not work properly. This gives the opportunity for the infections to get in to our body and produce various diseases. So Leukaemic patients have following symptoms.

·         Fever – The main symptom of infection is fever. So, if you have fever most of the time, then your immune system is defective. Leukaemic patients experience fever most of the time. Some of them have fever all the time. It is more uncomfortable and distressing.

·         Recurrent infections – Leukaemic patients gets more infections. They have more attacks of cough, cold, fever and other diseases.

3.      Symptoms due to reduced platelets

Platelets are also another type of cells which are produced in the bone marrow. As the marrow cells proliferate abnormally, there is less space for the megakaryocytes to divide and produce platelets. The function of the platelets is to produce a blood clot in places where there is an injury in the blood vessels, so more blood wont leak from the damaged vessel. When the platelets reduce in number this process does not occur. So, wherever there is damaged blood vessel, more blood tend leak out in to the skin. This results in bleeding and bruising. Look at your skin carefully. See if there are any bruises that you are not aware about. More the bruises, more the severity of the disease

4.      Lymphadenopathy

Lymphadenopathy means enlarged lymph nodes. So, if you want to find out whether you have Lymphadenopathy, first you have to know where the lymph nodes are. Then you have to carefully palpate those areas to see whether they are enlarged or not. How to palpate lymph nodes will be discussed later in my posts.

5.      Hepatosplenomegally

This is enlargement of the spleen and the liver. Methods to find whether they are enlarged or not, will be discussed later.

6.      Testicular enlargement

7.      Cranial nerve palsies

References : Kumar P and Clark M, 2009. Clinical Medicine. 7th ed.

Types of Leukaemia.

As we discussed in my previous post, leukaemia is a cancer of the blood producing cells. But, those of you who have leukaemia or know someone who have someone having leukaemia may know that there are several types of leukaemia. There are two major categories of leukaemia. They are,

1.      Acute Leukaemias

2.      Chronic Leukaemias

The above classification is done according to the speed of the evolution of the disease. In acute leukaemias the changes in the cells occur very rapidly. So the dividing cells have very small amount of time to differentiate. Therefore the cells found in acute leukaemias are mainly those belonging to the initial steps of the maturation process. Those cells in the initial process of dividing are called blast cells.  In chronic leukaemias the changes occur slowly over years. So the cells have more time to differentiate, but still the cells are not normal in structure or in function. 

These two Types of Leukaemias are further classified as following.

1.      Acute Leukaemias

a.      Acute Lymphoblastic Leukaemia – As the name implies the predominant cells in this category are lymphoblasts.

b.      Acute Myeloblastic Leukaemia – The prominent cells are cells in the myeloid lineage.

2.      Chronic Leukaemias

a.      Chronic Lymphatic Leukaemia – Lymphocytes are predominant cells.

b.      Chronic Myeloid Leukaemia – Cells in the myeloid lineage predominate.

French American British Classification of Acute Lymphocytic Leukaemia

1.      L1- Small round blast

2.      L2- Large pleomorphic blast

3.      L3- Very large blasts with vacuolated cytoplasm

French American British Classification of Acute myeloid Leukaemia

1.      M1- No differentiation

2.      M2- Minimal differentiation

3.      M3- promyelocytic

4.      M4- Myelomonocytic

5.      M5- Monocytic

6.      M6- Erythroid

7.      M7- Megakaryocytic

Leukaemia

What is Leukaemia?

Many of you must know that there is a disease called leukaemia, but some may not know what exactly happens in this disease. Simply saying it is a cancer of the blood cells. As many of you a cancer means abnormal growth of the body tissue. In leukaemia, the abnormal growth occurs in blood cells. To understand the disease process clearly, let’s have a clear idea about the blood cells in our body.

Following are the types of blood cells present in our body.

1.      Red blood cells

2.      White blood cells

a.      Neutrophils

b.      Eosinophils

c.       Basophils

d.      Lymphocytes

e.      Monocytes

3.      Platelets

All these cells are produced in the bone marrow. Bone marrow, as the name implies is placed within the bones. The following simple picture showing the structure of the bone will help you to understand it more clearly. Many of us think that bones are hard structure with no cavity, but it is wrong. There are small cavities within each bones and within those cavities lie the cells which divide (proliferate) and produce blood cells.

 Even though there are several types of blood cells, all of them originate from a single type of cell. They are called pluripotential cells. This mother cell is not like the daughter cells. The mother cells proliferate and produce daughter cells. The initial these first set of daughter cells are a little different from the mother cell. Like vise the daughter cells also divide and produce more cells. This process is called cell differentiation. These new cells also differ from the mother cell and from each other. This process keeps on happening till the final matured blood cells are produced. The more detailed outline of this process is illustrated in the following diagram.

 So, when the dividing process of these cells happens in an uncontrolled way, so the above mentioned maturation process does not occur. This results in filling the bone marrow with a lot of undifferentiated or abnormally differentiated blood cells. Then these abnormal blood cells are released in to the blood stream. Finally the bones get defected and the blood becomes unable to perform its functions correctly as its containing blood cells are defective.