Friday, 14 November 2008

What are the causes of a normocytic anaemia?

The best way to usefully classify anaemias is by the size of the red blood cells, which can therefore be microcytic, normocytic or macrocytic.

There is then an appropriate algorithm to discover the cause of each of these categories, but in the case of normocytic anaemias, the list is rather short.  So long as you're not considering aplastic anaemias or a pancytopenia, there are basically only three causes; the odds of it not being one of the following three are vanishingly small:
  • Anaemia of chronic disease
  • Renal failure
  • Acute blood loss
And, what's more, the three are easy to tell apart.  Simply measuring the standard electrolytes (especially urea and creatinine) will tell you if you are dealing with renal failure.  A significant acute blood loss should be easy to confirm with the patient (or alternatively look on the floor next to the unconscious patient), and anaemia of chronic disease is usually detectable on history, examination and special investigations.

It's not often that medicine hands you such a short list, so grab it with both hands!

No comments:

Post a Comment