Volume 1

The haemolytic anaemias, congenital and acquired / by J.V. Dacie.

  • Dacie, John V. (John Vivian), Sir.
Date:
1960-1967
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The haemolytic anaemias, congenital and acquired / by J.V. Dacie. Source: Wellcome Collection.

    18/396 (page 6)
    The distinction between an extravascular and an intravascular mechanism of haemolysis was made as early as 1901 by Hunter. Referring to “chronic hcematocytolysis ” (p. 363), he said: “They [the red corpuscles] become spherical, deeper in colour, and retain their haemoglobin to the last. In this form they continue to circulate until finally they are enclosed within the active cells of the spleen, or leucocytes of the blood, and are stored up within the spleen or in the capillaries of the liver ” [author’s italics]. He then went on to referto “acute hcemocytolysis ” (p. 364), saying: “The second process is marked by a different series of phenomena. The first of these is a liberation of haemoglobin from the corpuscle. It escapes from the corpuscle, either alone, or in combination with the albuminous stroma. Its fate is not, as in the former case, to be taken up by splenic cells or leucocytes within the blood, but it is carried to the liver in the portal blood, where it is taken and broken up by the liver cells.” EVIDENCE FOR AN INCREASED RATE OF HAEMOLYSIS As the bile and faecal pigments are largely derived from the catabolism of haemoglobin, it is natural to expect increased production and elimination of these substances whenever the rate of erythrocyte destruction is increased. Hyperbilirubinaemia. In haemolytic anaemia the plasma bilirubin concentration usually lies between 1 and 3 mg. per 100 ml. Occasionally, it is within the normal range; it is rarely above 5 mg. per 100 ml. The direct Hijmans van den Bergh reaction is usually negative or delayed positive in uncomplicated cases. The bilirubin concentration, however, is an unreliable measure of haemolysis, as it depends not only on the amount of pigment produced, but also on the efficiency of the liver in excreting it. Moreover, the total amount produced depends not only on the rate of haemolysis but also upon the total number of erythrocytes present. For instance, the same amount of bilirubin might be expected to be produced per day by the destruction of 5% of a patient’s erythrocytes when the total count was 5,000,000 per cu. mm. as by the destruction of 25% of the erythrocytes when the count was 1,000,000 per cu. mm. Other things being equal, therefore, the highest bilirubin levels might be expected in patients with the highest erythrocyte counts. In practice, however, this expected correlation is seldom found, as the patients with the highest counts are usually those in whom the rate of haemolysis is not great, i.e., they are patients in whom compensation for haemolysis is possible (see p. 26). It is probable that in those patients in whom the plasma- bilirubin level is normal despite evidence of increased haemolysis, the normal levels are maintained by the ability of the healthy liver