Blood disorders

Chapter 28 Blood disorders



Chapter contents


Anaemias 209

Thalassaemia 211

Leukaemia 211

Haemostasis 211

Antiplatelet drugs 212

Haemophilia 215

Red blood cells (erythrocytes) perform two functions:


• They transport oxygen from the lungs to the tissues of the body: they are able to perform this task because of the haem-based structure they contain (haemoglobin; see Chapter 13 ‘Vitamins and minerals’, p. 96).

• They catalyse the reversible reaction between carbon dioxide and water, thus enabling the removal of large amounts of carbon dioxide from the body tissues: erythrocytes contain the enzyme carbonic anhydrase, which makes it possible for the blood to transport carbon dioxide in the form of bicarbonate ions (HCO3−) (see Figure 18.3, p. 135).

Red blood cells are so constructed as to be able to deform to squeeze through capillary walls without rupturing. Their life span is relatively short (around 120 days); mature erythrocytes have no nucleus.




Erythropoietin


Around 90% of the hormone erythropoietin is produced by the kidneys; the rest is produced by the liver. As erythropoietin controls the rate of red blood cell production, it follows that patients are likely to become anaemic in cases of severe kidney disease (or their removal). This is worth bearing in mind if you have an anaemic patient with a chronic kidney condition.



Anaemias



Iron-Deficiency Anaemia (Microcytic Anaemia)



• Usually discovered with a full blood count (Chapter 41 ‘Scientific tests’, p. 331) and is one of the most common types of anaemia.

• There is not enough iron in the body to form haemoglobin.

• Blood cells are of normal size and content, but are fewer in number than normal.

• Can vary from mild, with no signs or symptoms, to severe, in which the patient experiences extreme fatigue and weakness.

For reasons for iron deficiency, see Chapter 13 ‘Vitamins and minerals’ (p. 97).



• Treatment



• Iron supplementation.


Pernicious Anaemia



• Macrocytic, normochromic anaemia: blood cells are large, with a normal amount of haem.

• Autoimmune type of anaemia: due to the patient producing antibodies against the intrinsic factor needed for efficient absorption of vitamin B12.

• Pernicious anaemia can also refer to the anaemia caused by a deficiency of vitamin B12 due to other causes (see Chapter 13 ‘Vitamins and minerals’, p. 105).


• Treatment



• Lifelong injections of vitamin B12.


Megaloblastic Anaemia


Generalized description of a type of anaemia that is usually the result of vitamin B12 and folate deficiency. The red blood cells are larger than normal and there is an accompanying reduction in the numbers of white blood cells and platelets.



• Treatment


Vitamin B12 and folate supplementation (see Chapter 13 ‘Vitamins and minerals’, p. 105).



Aplastic Anaemia


The bone marrow stops making an adequate number of blood cells so there is a noticeable reduction of blood cells, including red blood cells.



• Treatment



• Nearly all patients require transfusions.

• Ultimately, treatment will be directed at the cause of anaemia, e.g. the patient might have leukaemia and will therefore require the appropriate treatment for that condition.


Sickle-Cell Anaemia



• The body makes abnormal-shaped red blood cells.

• Genetic: commonly found in people of sub-Saharan African descent.


• Treatment



• Transfusions.

• Oral antibiotics from 2 months to 5 years to prevent pneumonia: it is therefore important to consider health of the gastrointestinal tract of such patients (see Chapter 17 ‘Metabolism’, p. 132).


Thalassaemia



• Similar to sickle-cell anaemia.

• Genetic: very often of Mediterranean descent.


Treatment


Transfusions.


Note: with both sickle-cell anaemia and thalassaemia, avoid supplementation with omega 3 oils.

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Jul 22, 2016 | Posted by in PHARMACY | Comments Off on Blood disorders

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