VII EFFECTS OF DEFICIENCY 419 



VII. Effects of Deficiency 



A. IN ANIMALS 

 H. J. ALMQUIST 



The pathology of vitamin K deficiency is unique among the vitamins 

 because the only primary effect yet known on any tissue is that upon the 

 prothrombin level of the blood. The prothrombin content of blood is greatly 

 decreased, and the clotting time is markedly prolonged. Thus the occurrence 

 of subcutaneous and intramuscular hemorrhages is frequently observed. 



B. IN HUMAN BEINGS 

 CHARLES A. OWEN, JR. 



A deficiency of vitamin K is characterized by a bleeding tendency secon- 

 dary to an alteration of the coagulability of the blood. The deficiency may 

 result from ingestion of insuflficient vitamin K, lack of bacterial synthesis 

 of the vitamin within the intestinal tract, inadequate intestinal absorp- 

 tion, or hepatic inability to utilize the available vitamin K. 



1. Hemorrhage Resulting from a Deficiency of Vitamin K 



Serious abnormalities of the blood coagulation mechanism may be present 

 without any evidence of bleeding. However, it is frequently stated that 

 when the plasma prothrombin falls to about 20 % of normaP the danger of 

 bleeding exists; this is based on repeated observations that bleeding only 

 infrequently occurs in vitamin K deficiency when the prothrombin is above 

 this level. 



Prior to the discovery of vitamin K and recognition of its deficiency in 

 obstructive jaundice, bleeding was most commonly seen after surgical cor- 

 rection of a biliary obstruction. ^ This is now rare because of the generous 

 use of vitamin K in biliary surgery. At the present time hemorrhage from 

 injudicious use of dicoumarol — an "antagonist" of vitamin-K — is probably 

 commonest.* 



The bleeding caused by vitamin K deficiency may be first recognized 

 by slow oozing from the mucous membranes of the nasopharynx, by the 

 appearance of ecchymoses associated with mild trauma, or in surgical cases 

 by hematomas and persistent bleeding at the site of operation. Massive 

 hemorrhage may occur beneath the skin and within muscles, particularly 

 of the extremities. Hemorrhagic disease of the newborn is often first sus- 



1 Values as high as 35 to 40% [K. M. Brinkhous, H. P. Smith, and E. D. Warner, 

 Am. J. Med. Sci. 196, 50 (1938)] and as low as 5% [F. Roller and P. Frick, Helv. 

 Chim. Acta 32, Part 1, 717 (1949)] have been suggested. 



2 E. W. Boland, Proc. Staff Meetings Mayo Clinic. 13, 70 (1938). 



3 I. F. Duff and W. H. Shull, /. Am. Med. Assoc. 139, 762 (1949). 



