Hemoglobin A2 the clinical significance

Haemoglobin is the substance in the blood that carries oxygen around the body. The type of Adult haemoglobin in person is determined by the inherited genes from parents. Genes always come in pairs one from the father and one from the mother. Hence, every individual inherits two Adult Haemoglobin genes. The normal and most common Adult haemoglobin gene combination that an individual can inherit from their parents is Haemoglobin AA and is written as Hb AA.

Hemoglobin A2 (HbA2) is a normal variant of hemoglobin A .It has two alpha and two delta chains (α2δ2) and is found at low levels in normal human blood.The biological role of this protein is not yet known.

During the early embryonic period itself this is produced in the fetus, irrespective of the type of major Adult haemoglobin they have inherited from their parents.

From very early life in the womb the level of Haemoglobin A2 is between 1.5% – 3.5% and remains at this level at birth and through out adulthood.So in adult also the  normal amount of Hemoglobin A2 is 1.5-3.1% of all hemoglobin molecules, Hemoglobin A2 level vary depending on the underlying disease

Clinical significance of Hemoglobin A2

Haemoglobin A2 is a redundant haemoglobin because  this is  not an efficient at carrier of  oxygen in  the body, however, But it has certain clinical significance because it is useful for helping the laboratory to diagnose some genetic mutations of haemoglobin, based on the type of genetic mutation  and underlying disease the level of A2 will rise or fall.

Causes of Increased HbA2 levels

• Beta thalassemia
• Sickle cell anemia
• Megaloblastic anemia
• Hyperthyroidism
• Unstable Hemoglobinopathies
• Malaria (doubtfull cases) 

Causes of Decreased HbA2 levels

• Iron deficiency Anemia
• Alpha thalassemia
• Delta thalassemia
• Sideroblastic anemia
• Myelodysplastic syndromes
• Acute myelocytic leukemia (minor reduction)
• Hb Lepore 

Clinical significance of Osmotic Fragility

Osmotic fragility of red cells is defined as the ease with which red cells are ruptured (hemolysed) when they are exposed to hypotonic solution.

Osmotic fragility test assesses the integrity of the membrane of red cells.

Increased Osmotic Fragility is seen in the following

Cells which have a lower surface to volume ratio such as spherocytes from any cause have increased osmotic fragility is ssen in the following Conditions

• Hereditary»spherocytosis (HS)
• Autoimmune Hemolytic Anemias (A1HA)
• Hemolytic Disease of new bom
• Malaria
• Severe pyruvate kinase deficiency
• Other conditions in which spherocytes are found in the blood 

Conditions with decreased Osmotic Fragility

Cells which have a high surface to volume ratio such as thin/hypochromic/target cells have decreased osmotic fragility.

• Thalassemia
• Other hemoglobinopathies eg. HbC, HbS
• Iron deficiency anemia
• Sickle cel! anemia
• Post splenectomy
• Reticulocytosis
• Other conditions in which thin/target cells are found in the blood.

Clinical features of Hemolytic Anemia

Hemolytic anemia is characterised by features due to increased Hemolysis that is reduced  RRC life span and features due to Erythropoetic response of the bone marrow

Features due to Increased Hemolysis -Reduced  RRC life span

• Hemoglobin: reduced
• Increase in unconjugated bilirubin
• Elevated LDH
• Increased AST
• Reduced  Haptoglobin
• Increased  Urobilinogen in urine (& stool)
• Increased  Stercobilinogen in stool
• Hemoglobinuria (intravasculae  hemolysis)

Features due to Ervthropoetic response of the bone marrow

• Increase in  Reticulocytes (Reticulocytosis)
• Increase in  MCV/MCH  this is due to the increased number of reticulocytes
• Peripheral smear - Macrocytes, Polychromasia & sometimes nucleated red cells in smear. Routine bloodfilm shows a varietyt of abnormal morphological type of red cells such as Schistocytes ,Spherocytes  etc.
• Bone narrow shows erythroid hyperplasia( Myeloid: Erythroid Ratio is decreased)with raised iron stores.
• X Rays of bones show evidence of expansion of marrow space, especially in tabular bones & in skull rsulting in bossing of skull 

Oral Manifestations of vitamin B12 deficiency

• Tongue may be large  called as Macroglossia
• Tongue may be smooth due to loss of papillae (Atrophic Glossitis)
• Tongue may show red patches on red lines on the ventrum (Moeller's glossitis)
• Tongue may be red and inflamed (Sore tongue)
• Angular cheilitis may be associated
• Oral ulcers may be seen

Anemia of chronic renal failure

• Anemia of chronic renal failure is normocytic normochromic, hypoproliferative anemia
• The level of anemia correlates with the severity of underlying renal failure
• The anemia is primarily due to a failure to produce adequate level of Erythropoetin and a reduction in red cell survival.
• Patients usually present with normal serum iron, TIBC & ferritin levels
• Erythropetin therapy is the mainstay of treatmentto improves anemia symptoms
• Dialysis typically has little effect with regard to correcting the anemia.
• Peritoneal dialysis (ambulatory) usually improves anemia while hemodialysis may cause an associated iron deficiency anemia
• Iron deficiency anemia may however be seen in some patients with CRF who are maintained on chronic hemodialysis due to loss through the dialysis procedure.

Clinical assessment of anemia

What is anemia?


What are the symptoms of anemia?


What is the significance of hand examination in Anemia?


What are the common causes of severe anaemia ?


When will you clinically diagnose iron deficiency anaemia ?


What are the causes of glossitis and angular stomatitis ?

What are the clinical features of haemolytic jaundice?

Following are the clinical feaatures of hemolytic jaundice

• Acholuric  urine means freshly passed urine is of normal colour as there is no bilirubin in urine but if the urine sample is kept for sometime, this will turn dark yellow due to conversion of urobilinogen to urobilin by oxidation.
• Stool is high-coloured due to excess amount of stercobilinogen and stercobilin.
• Jaundice is usually mild and there is lemon-yellow tinge of bulbarconjunctlva. 
• Serum bilirubin is usually less than 6 mg/dl and this is predominantly of unconjugaled variety.
• Anaemia is present .It can be mild, moderate or severe, according to the degree of haemolytic process.
• Splenomegaly, is very characteristic of haemolytic anemia

What are the causes of  Haemolytic jaundice?

Following are the common causes of haemolytic jaundice

• Thalassaemia.
• Mismatched blood transfusion.
• Snake bite (Viperidae group).
• Malaria (specially falciparum malaria).
• Rh incompatibility.
• Primaquine or sulphonamide-induced (in GePD deficiency).

What are the causes of glossitis and angular stomatitis ?

Glossitis is seen in the following conditions

• Riboflavin deficiency—Magenta-coloured tongue.
• Iron deficiency anaemia.
• Nicotinic acid or vitamin Bi2 deficiency—The tongue is red. swollen, painful and is known  as  'raw-beefy tongue'.
• Folic acid deficiency.
• Bald tongue (complete atrophy of papillae)— A finding seen in in severe iron deficiency anaemia
• Median rhomboid glossitis— A lozenge-shaped denuded area in the middle of the tongue posteriorly. This  is a congenital abnormality and as it feels nodular, it should be differentiated from malignancy of the tongue.

Angular stomatitis

It is the inflammation of the skin at the angle of mouth.It is seen in following conditions

• Excessive use of tobacco, alcohol or betel-leaf.
• Improperly-fitted denture.
• Iron deficiency anaemia.
• Riboflavin, nicotinic acid and pyridoxine deficiency.
• Herpes labialis at the angle of mouth.
• Starvation or malnutrition.

When will you clinically diagnose iron deficiency anaemia ?

Clinical features of iron deficiency anemia are

Presence of anaemia.

H/o pica that is eating of strange non-nutrient items such as 

• Eating of clay is called  as geophagia. 
• Eating of Ice is called as pagophagia.
• Eating of cornstarch is called  as amylophagia   

Glossitis.

Angular stomatitis, cheilosis.

Koilonychia.

Dysphagia due to Plummer-Vinson syndrome or Paterson-Kelly syndrome.

Mild splenomegaly, rarely seen in iron deficiency anemia

What are the common causes of iron deficiency anaemia?

• Nutritional deficiency.
• Bleeding peptic ulcer.
• Bleeding haemorrhoids.
• Hookworm infestation.
• Malabsorption syndrome.
• Menorrhagia.
• Pregnancy, lactation.

What is the significance of hand examination in Anemia?

Following are the significance of hand examination in anemia

Nail beds and palm give an indication of presence of anaemia.

Colour ol palmar creases can give a clue to the degree of anaemia. 

When they are as pale as the surrounding skin, the haemoglobin level  is expected to be < 7 g/dl.

In ophthalmoscopy if the retina seems very pale, the haemoglobin concentration is usually < 4 g/dl.

Koilonychia gives a clue lo the type of anaemia, it is seen in  iron deficiency anaemia.

In severe anaemia, capillary pulsation may be felt.

Presence of splinter haemorrhage or osler's node points towards subacute bacterial endocarditis.

Anaemia with finger deformities may indicate underlying  rheumatoid arthritis

What are the symptoms of anemia?

Low haemoglobin may produce following symptoms

Weakness, fatigue. lassitude, anorexia,palpitation, breathlessness, anginal pain,light-headedness, giddiness, insomnia, tinnitus, tingling sensation in the extremities.

What are the clinical signs of anemia

Anemia may be associated with following clinical signs

General survey reveals  pallor, dyspnoea, ankle oedema

Cardiovascular features in severe anaemia :

• Tachycardia.
• Water-hammer pulse.
• Capillary pulsation
• Cardiomegaly.
• Hyperdynamic apex beat.
• Mitral systolic murmur due to functional MI (ring dilatation).
• Haemic murmur over the pulmonary area.
• Rarely mid-diastolic (non-rumbling) murmur in mitral area may be auscultated (due to relative stenosis at mitral valve) secondary to increased blood flow.

Gastrointestinal tract

Hepatosplenomegaly may be present associated with anemia

Respiratory system may reveals basal crepitations.

Nervous system  there may be features of polyneuropathy :sometimes, there is papilloedema.

Lymphoreticular system there may be presence of sternal tenderness.

What are the common causes of severe anaemia ?

Following are the common cause of severe anemia

• Nutritional.
• Hookworm infestation.(in developing countries)
• Hemetemesis and melaena (commonly from chronic duodenal ulcer or rupture of oesophageal varices
• Chronic bleeding haemorrhoids.
• Aplastic anaemia.
• Acute leukaemias.
• Thalassaemia.
• Uraemia.
• Menorrhagia.
• Carcinoma of stomach, lung, colon.
• Blood Transfusion is usually required when haemoglobin level goes below 7 gm/dl. 

What is anemia?

Definition of anemia

Anemia is defined as qualitative or quantitative diminution of RBC and / or haemoglobin concentration in relation to standard age and sex and clinically manifested by pallor.

Normally the mucous membrane and nailbed are pink in colour, depending on the amount of Hb in the circulating blood.Clinically, anemia is defined as pallor of the conjunctiva, oral mucosa, tongue, palm and nailbed. Usually pallor appears when the Hb < 10 mg percent, and pale palmar creases are seen when Hb < 8 gm percent.

The best site for examination of pallor of anemia is palmar creases and mucosa of the palate

What is disproportionate pallor ?

Pale complexion is seen in people without anemia also

This is a condition where pallor > anemia this is seen in CRF, hypopitultarism

In males the laboratory criteria for diagnosis of anemia is 

• Hemoglobin < 13 gm%
• PCV <42%
• RBC count < 4.5 million/mm1

In females the laboratory criteria for diagnosis of anemia is

• Hemoglobin < 12 gm%
• PCV < 36%
• RBC count < 4 million/mm3

In children anemia is diagnosed based on the following haemoglobin values

• 6 months to  6 vears : < 11 gm%
• 6 years  to 14 years : <12 gm% 

Which are the sites you should examine for pallor?

Pallor is best identified examining the following sites

• Lower palpebral conjunctiva , retract the patients lower eyelids downward and ask the patient to look upwards — both eyes should be examined at a time.
• Tongue, specially the tip and the dorsum.
• Soft palate.
• Nail-beds you should press the pulp of the finger to see the redness of nail bed.
• Gums soles and general skin surfaces.

Nail-beds are  known as the windows of the cutaneous capillary network.

What is the clinical classification of anemia ?

The normal haemoglobin concentrations in case of males and females are.

Males — 14.6 to 15.5 g/dl. 

Females — 13.3 to 14.6 g/dl.

14.5 g/dl may be taken as 100%.

Anemia is clinically classified as mild, moderate and severe types. As it is totally a clinical assessment ,it may not correspond with laboratory findings. The colour of the tongue as well as the conjunctiva are more reliable than other sites in adults.In children, palms and soles should be specially looked for.

Mild anaemia — 60-80% of Hb (9-12 g/dl).

Moderate anaemia — 40-60% of Hb (6-9 g/dl)

Severe anaemia — <40% of Hb (<6 g/dl). 

What is the difference between pallor and anemia?

Pallor (paleness) is the waxy appearance of skin and mucous membrane. Pallor  depends on thickness and quality of skin, as well as quality and amount of blood in the capillaries. The terms , pallor and anaemia are not interchangeable. There are many causes of pallor, and anaemia is one of the cause of pallor.  Anaemia is a pathological condition while pallor is a clinical entity. 

Clinical features and common causes of iron deficiency anaemia

clinical diagnosis of iron deficiency anaemia is done in the following situations

1)   Patient gives H/O 'pica' (Pica is eating of strange non-nutrient items such as clay(geophagia), ice(pagophagia) ,cornstarch(amylophagia).  Pica' is also noticed in pregnancy and some psychiatric disorder.

Associated with it  chronic blood loss from G. I. tract may be seen.

2)  Presence of Anaemia.

3)  Glossitis.

4)  Angular stomatitis, cheilosis.

5)  Koilonychia.

6) Dysphagia (Plummer-Vinson syndrome or Paterson-Kelly syndrome).

7)  Mild splenomegaly, rarely.

Common causes of iron deficiency anaemia are

1)  Nutritional deficiency.

2)  Bleeding peptic ulcer.

3)  Bleeding haemorrhoids.

4)  Hookworm infestation.

5)  Malabsorption syndrome.          

6)  Menorrhagia.   

7)  Pregnancy, lactation.      

What are the systemic manifestations of anemia ?

People with anemia may present to you with one or more of these symptoms.

Weakness, fatigue, lassitude, lightheadedness. giddiness, anorexia, palpitation, breathlessnes's. anginal pain, insomnia, tinnitus, tingling sensation in the extremities.

Anemia produces its effect on multiple systems.

1.General survey helps to detect 

a) Pallor 

b) Dyspnoea

c) Ankle oedema or anasarca.

2.Cardiovascular features in severe anaemia are the following

1) Tachycardia.
2) Capillary pulsation.
3) Water-hammer pulse.
4) Cardiomegaly.
5) Hyperdynamic apex beat.
6) Mitral systolic murmur due to functional MI (ring dilatation).
7) Haemic murmur over the pulmonary area.
8) Rarely mid-diastolic (non-rumbling) murmur in mitral area may be auscultated secondary to increased blood flow.

3) G.l. tract-examine for Hepatosplenomegaly.

4) Respiratory system -look for basal crepitation due to cardiac failure.

5) Nervous system    - sometimes there is papilledema.

6) Lymphoreticular system -sternal tenderness may be present.

What is the significance of examination of the hands in anaemia ?

Examination of hand is an important part of anemia evaluation because of the following

1. Paleness of nail beds and palm helps to detect the presence of anaemia.
2. Koilonychia or spooning of nail bed if present gives a clue to the type of anaemia, such as iron deficiency anaemia.
3. In severe anaemia, You may get capillary pulsation.
4. Presence of splinter haemorrhage or Osiers node indicates SBE.
5. Anaemia with finger deformities may be seen in rheumatoid arthritis.
6. Colour of palmar creases gives a clue lo the severity of anaemia. 

When they arc is as pale as the surrounding skin, usually has a haemoglobin level < 7 g/dl.

In ophthalmoscopic examination if the retina seems very pale, the haemoglobin concentration is usually < 4 g/dl.

What is anemia and how to detect it?

Definition of anemia:

It is defined as qualitative or quantitative diminution of RBC and / or haemoglobin concentration in relation to standard age and sex and clinically it is manifested by pallor.

Sites you will look to detect anaemia?

Following are the sites that should be examined:

Clinically we look for paleness of the skin/mucous membrane

1. Lower palpebral conjunctiva (examined by retracting the lower eyelids downward and ask the patient to look upwards, both eyes are examined at a time).
2. Tongue, especially the tip and the dorsum of tongue.
3. Soft palate.
4. Nail beds (press the pulp of finger tip to see the redness of nail bed).
5. Palms, soles and general skin surfaces

In adults the colour of the tongue and the conjunctiva are more reliable than other sites. In children, palms and soles are to be specially looked for.

How will you clinically classify the anemia?

Based on clinical examination anaemia Is clinically classified as mild, moderate and severe types. As it is totally a clinical assessment sometime this may not correspond with laboratory findings

Mild anaemia          -60-80% of Hb (9-12 g/dl).

Moderate anaemia  - 40-60% of Hb (6-9 g/dl)

Severe anaemia       - <40% of Hb (<6 g/dl).

The normal haemoglobin concentrations varry in males and females.

Males    -14.6 to 15.5 g/dl. 

Females - 13.3 to 14.6 g/dl.

* 14.5 g/dl may be taken as 100%.