Pernicious Anaemia or Addison's Anaemia
Pernicious anaemia is also known as Addison's anaemia and is classified under groups of megaloblastic anaemia. It is caused by failure in the secretion of intrinsic factor by the gastric parietal cells and inability to absorb vitamin B12. It is most common cause of vitamin B12 deficiency in adults. Lack of gastric parietal cells results inability to absorb vitamin B 12.
Aetiology of Pernicious anaemia:
Pernicious anaemia occurs between the ages of 45 to 65 years and affects females more than males. The disease is rare before the age of 30 years. Achylia gastrica is invariably present in pernicious anaemia. The gastric mucosa fails to secrete a substance (intrinsic factors) required for the absorption of vit. B 12 from the gastro intestinal tract.
Causes of Pernicious anaemia:
Human body needs vitamin B 12 to make red blood cells. Source of this vitamin are Meat, Poultry products Shellfish eggs and dairy products. To absorb, vitamin B 12, human body uses a special protein known as intrinsic factor, secreted by gastric cells which are absorbed in the terminal part of small intestine.
In case stomach does secrete adequate intrinsic factor, intestine is unable to absorb vitamin B 12.
Rarely, infants and children born without secreting capacity of intrinsic or ability to absorb both intrinsic factor and vitamin B 12 in the small intestine.
In congenital pernicious anaemia, defective genes are inherited from both parents and causes pernicious anaemia.
Pernicious anaemia may occurs in following conditions:
• Family history of pernicious anaemia
• Diabetes mellitus
• Intestinal disorders
• Thyroid disfunctions
• Atrophic gastritis (weak stomach lining)
• Lack of immune system which make intrinsic factor or lack of intrinsic factor itself.
Sources of vitamin B12 deficiency :
Most common sources of vitamin B12 are:
• Meat, Eggs, Poultry and Shellfish
• Milk and dairy products
• Fortified cereals, germinated wheat, rice &barley
• Peas, Peanuts, Beans,Soyabeans &Lentils etc.
• Spinach and other green leafy vegetables
Clinical manifestations of Pernicious anaemia:
• Onset of disease is insidious
• Degree of anaemia is often much more when patient consult the doctor
• There is no specific sign & symptoms observed in early stage of anaemia
• Pallor skin and mucous membrane with faint lemon-yellow tint
• Soreness of tongue
• Recurrent diarrhoea & constipation
• Weakness, fatigue or lack of stamina
• Loss of appetite
• Breathlessness during walk & exercise
• Tongue is painful, red, raw, sourness with ulcers later mucous membrane become smooth and atrophic
• Spleen is seldom palpable
• Vitamin B12 deficiency for longer time causes nerve damage resulting confusion, depression, loss of balance, numbness and tingling of hands & feet
• Gastric analysis show achlorhydria
• Urine show increased urobilinogen in relapse stage of P.A.
• Blood smear examination shows a macrocytic picture of anaemia. Mean corpuscular volume is raised & macrocytes are fully stained. There is marked Anisocytosis and Poikilocytosis and many cells are oval in shape. In severe cases of anaemia few nucleated red cells are seen in peripheral blood.Reticulocytes number is less than 1%.There may be leucopoenia with decreased granulocytes. Serum bilirubin level is raised.
How diagnosis of Pernicious anaemia is made?
Pernicious anaemia is insidious in nature. There is no specific single test to confirm the disease. It is suspected when blood smear shows large, fragile, immature erythrocytes (megaloblasts). Mean Corpuscular Volume (MCV) is high while Mean corpuscular Haemoglobin Concentration (MCHC) is normal. Pernicious anaemia is a macrocytic, normochromic anaemia. It is also diagnosed by estimating vitamin B12 deficiency i.e. vitamin B12 level in the serum by means of radio active cobalt (e.g. Schilling Test). Atrophic gastritis type A is confirmed by gastoscopy and stepwise biopsy.
Prevention of Pernicious anaemia:
Prevention of disease is made by:
• Early detection of disease
• Early treatment of vitamin B12 deficiency can minimise the complications
Other names of Pernicious anaemia:
• Addison's anaemia
• Congenital Pernicious anaemia
• Juvenile Pernicious anaemia
• Megaloblastic anaemia
• Macrocytic achylic anaemia
• Vitamin B12 deficiency (mal absorption) anaemia
Treatment of Pernicious anaemia:
Pernicious anaemia is treated in two ways
• General treatment
• Specific treatment
General treatment :
In this regime of treatment Pernicious anaemia patient is kept in bed until haemoglobin is about 7 gm %. Blood transfusion is based on clinical state of patient. When haemoglobin level is under 4 gm %, blood transfusion is given.
Specific treatment :
Pernicious anaemia can be treated both by parenteral or oral route of vitamin B12.Injection of vitamin B12 is either given daily or weekly at first then one injection every month. In some cases parenteral and oral treatment is given simultaneously.
Vitamin B12 is also available in the form of nasal spray and gel. Underlying causes of vitamin B12 deficiency must be treated. Physical activities are limited till anaemia symptoms subside.