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.