Hereditary haemophilia : deficiency in the coagulability of the blood the only immediate cause of the condition / by Thomas Addis.

  • Addis, Thomas, 1881-1949.
Date:
1910
Catalogue details

Licence: In copyright

Credit: Hereditary haemophilia : deficiency in the coagulability of the blood the only immediate cause of the condition / by Thomas Addis. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    4/24 (page 14)
    HEREDITARY HAEMOPHILIA: DEFICIENCY IN THE COAGULABILITY OF THE BLOOD THE ONLY IMMEDIATE CAUSE OF THE CONDITION1 By THOMAS ADDIS In 1896 Wright first definitely established the fact of the delayed coagula- tion of the blood in this disease. Since then it has been confirmed by Sahli, Morawitz and Lossen, Weil, Baum, Kottmann and Lidsky, Nolf and Herry, and others. No one using modern methods has found a normal coagulation time in haemophilic patients. But the constancy of this pathological feature does not exclude the possibility that there are other causes at work in producing the symptoms of the disease. There are certain difficulties in the way of accepting it as the sole cause. Indeed, when some of the clinical phenomena are considered, it would seem that a deficient coagulability of the blood is inadequate in itself to explain all the facts. If the blood in haemophilia were incoagulable then indeed it would not be necessary to look further. But it is not. On the contrary, very large clots form in the wounds of these patients, though blood may continue to ooze from them for hours or days. If then the diminution in coagulability is not of such a degree as to prevent coagulation in the wound, how can it be regarded as the direct cause of the continuance of the haemorrhage ? Again, how does it account for the fact that the wound cavity may soon be filled with clot which completely arrests the bleeding, and that nevertheless hours later haemorrhage may recur and continue indefinitely ? Surely during the period when the bleeding had ceased, the blood in the wound must have had ample opportunity for complete coagulation? These difficulties might be explained by assuming that there was a deficient formation of fibrin, so that the clot was loose and easily dislodged; but this appears to be negatived by the results of Sahli’s experiments. He showed that, ex vitro at least, the fibrin formed in the delayed coagulation of haemophilic blood was as great in amount as that produced in the more rapid clotting of normal blood, and that it is im- possible to distinguish one clot from the other, both are equally firm and dense. Wright, though holding fast to the deficient coagulability as the proxi- mate cause, recognizes that it does not explain all the facts. Sahli, who attempts a complete theory of the condition, is obliged to assume a hypothetical chemical defect in the tissues of the vessel walls, which consists of an absence in them of the substance, thrombokinase, which normally initiates the process of coagu- 1 The work in connexion with this paper has been done under the conditions of tenure of a Carnegie Research Scholarship.