Anaemia

Introduction

Anaemia is the most common disorder of blood which affecting about a quarter of people globally. Iron deficiency anaemia affects nearly 1 billion. It is more common in females, children, pregnant women and elderly. Anaemia increases costs of medical care and lowers a person’s productivity through a decreased ability to work.

What is Anaemia?

Anaemia is defined as a decrease in the amount of red blood cells (RBCs) or the amount of haemoglobin in the blood. When a person is suffering from anaemia, he or she has a lowered ability of the blood to carry oxygen.

In men, the level of normal haemoglobin should be between 13-14g/dl, while women 12-13g/dl.

Sign and Symptom of Anaemia

When the course of anaemia is chronic, the symptoms may be undetected and are often vague. The signs and symptoms can be related to the underlying cause of the anaemia itself. The patients may feel tired and weak; has poor concentration, palpitation or shortness of breath on exertion. Acute anaemia often have greater symptoms which may include confusion, feeling ill and an increased desire to drink fluids. There needs  to be significant drop in haemoglobin before the signs become apparent. The patients may be noted to be pale, having koilonychias (in iron deficiency) , jaundice (haemolysis), thalassaemic facies and bone deformities (found in Thalassaemia major) or leg ulcers (seen in sickle-cell disease). In severe anaemia, there may be signs of hyper dynamic circulation: fast heart rate, bounding pulse, heart enlagement and failure.

Children with anaemia may display behavioural disturbances and reduce scholastic performance as a direct result of impaired neurological development during infancy.

Causes

Broadly, anaemia can be classified into four main types:

  1. Impaired red blood cell (RBC) production
  2. Increased RBC destruction (haemolytic anaemia)
  3. Blood loss and
  4. Fluid overload (hypervolemia)

Several of these may interplay to cause anaemia eventually. Indeed, the most common cause of anaemia is blood loss, but this usually does not cause any lasting symptoms unless a relatively impaired RBC production develops, in turn most commonly by iron deficiency.

  1. Impaired production
    Disturbances of proliferation and differentiation of stem cells caused by genetic disorders and systemic disorders (renal failure and endocrinal diseases) can lead to anaemia. These conditions can impair the production of red cells. Examples of these abnormalities are pure red cell aplasia, Fanconi anaemia and chronic renal failure. Another condition that can cause impaired red cell production is nutritional deficiencies (folate, B12 and iron). The lack of these elements can disturb the proliferation and maturation of young red cells (erythroblast). Iron deficiency is very common among pregnant mothers and elderly individuals. Iron deficiency anaemia has small red cells (microcytic anaemia) and folate and B12 deficiency anaemia has big red cells (megaloblastic anaemia). The size of red cells can be deduced from the measurement of mean corpuscular volume (MCV). Another cause of impaired production of red cells is bone marrow infiltration by the cancer cells and granuloma or chronic infection.
  2. Increased destruction
    The patients with haemolytic anaemia usually have jaundice and elevated lactate dehydrogenase level. Abnormalities of red cell membrane, enzyme deficiencies, and haemoglobin structures can cause red cells to haemolyse. In addition to that, autoantibodies generated by certain infections, cancers and illnesses also can cause haemolysis. Examples of patients with haemolytic anaemia are G6PD deficiencies, thalassemia, autoimmune haemolytic anaemia, sickle cell anaemia, paroxysmal nocturnal haemoglobinuria.
  3. Blood loss
    Anaemia from blood loss can be acute or chronic depend on the amount and rate of bleeding. Blood loss can be due to frequent blood sampling (anaemia of prematurity), trauma, gastrointestinal loss, menstruation or abnormal uterine bleeding, antepartum or postpartum haemorrhage.
  4. Volume overload (hypervolemia)
    General causes of hypervolemia include excessive sodium or fluid intake, sodium or water retention and fluid shuft into the intravascular space causing the haemodilution and drop in haemoglobin. For example anaemia of pregnancy is induced by blood volume expansion experienced during pregnancy. Another term for this type of anaemia is physiological anaemia.

Diagnosis

Anaemia is detected from a test called full blood count (FBC) done by automatic counters that are available in any hospital or health centre. FBC is done as part of routine investigation for any patient who is admitted to a hospital for whatever reason or upon request from a volunteer. Apart from reporting the number of red blood cells and the haemoglobin level, the automatic counters also measure the size of red blood cells, which is an important tool in distinguishing between the causes of anaemia. To complete the examination of the blood cells, the morphology examination of stained blood cells (full blood picture-FBP) on the slide using microscope is compulsory. The morphology of the red cells, white cells and platelet can be visualized to detect any evidence of bone marrow pathology, leukaemia and some causes of anaemia.

In some centres, automated counters can measure a reticulocyte count. A reticulocyte count is a quantitative measure of the bone marrow’s producton of new red blood cells. If the degree of anaemia is significant, even a “normal” reticulocyte count can be done manually following special staining of the blood film.

In addition to FBC and FBP, there will be other tests to support in searching for the cause, for example, ESR, ferritin, seum iron, transferrin, RBC folate level, serum vitamin B12, haemoglobin electrophoresis and renal function test (e.g. serum creatinin). All these tests will be done according to the clinical presentstion of a patient. Bone marrow examination will be offerd if the clinical judgment is warranted to look for leukaemia, bone marrow failure or infiltration.

Treatments

Treatments for anaemia depend on causes and severity. Iron and vitamin supplements given orally (folic acid or vitamin B12) or intramuscularly (vitamin B12) will replace deficiencies. Vitamin C aids in the body’s ability to absorb iron, so taking oral iron supplements with orange juice is a benefit. In anaemia of chronic disease, associated with chemotherapy or renal disease, some clinicians prescribe recombinant erythropoietin or epoetin alfa to stimulate RBC production.

Blood transfusion among asymptomatic patients is not recommended unless haemoglobin level is below 6-8g/L. Patients with comorbidities such as heart disease, respiratory impairment or ongoing bleeding with hypovolemia are recommended for transfusion when haemoglobin below 7 or 8 g/dl.

Prevention

You are advised to check your FBC at least 6 months even when you have no symptom, even more so., when you have family history of blood transfusion, thalassaemia or leukaemia. You can walk in to any health care facilities and ask for a test for FBC to be done for you.

Support Group

There will be support groups such as Malaysian Society of Thalassaemia which is actively involved in caring for thalassaemia patients and families

Address:
Thalassaemia Association of Malaysia
3rd Floor, National Cancer Society Building
Jalan Raja Muda Abdul Aziz
50300 Kuala Lumpur
Tel :+60326941141

References

  • Hoffbrand A et al: 2005. Postgraduate Haematology, 5th Edition

 

Last Reviewed : 10 February 2015
Writer : Dr. Sinari bt. Salleh
Accreditor : Dr. Ilunihayati bt. Ibrahim