Felis ISSN 2398-2950

Vitamin K1 responsive coagulopathy (Devon Rex)

Contributor(s): Severine Tasker

Introduction

  • Cause: reduced activity of vitamin K dependent clotting factors (II, VII, IX and X) due to an enzyme defect (gamma-glutamyl carboxylase) resulting in inadequate activation of vitamin K1 dependent clotting factors .
  • Signs: hematoma, conjunctival or scleral hemorrhage, hemarthrosis, hemothorax, hemoabdomen, post-operative hemorrhage, spontaneous bleeding, may be clinically silent.
  • Diagnosis: significant prolongation of prothrombin and activated partial thromboplastin times.
  • Treatment: Vitamin K1 administration, likely required lifelong. Appropriately typed and cross-matched blood transfusion may also be required in patients with evidence of transfusion triggers
  • Prognosis: fair. Vitamin K1 is likely to be required life-long.

Pathogenesis

Etiology

  • Affected Devon Rex cats have a defect that causes an abnormal gamma-glutamyl carboxylase (carboxylase-epoxidase) enzyme.

Pathophysiology

  • Gamma-glutamyl carboxylase is needed for activation of the vitamin K-dependent factors with vitamin K hydroquinone as a cofactor. In affected cats this enzyme has decreased affinity for both vitamin K hydroquinone and the inactive coagulation factors. When inactivated coagulation factors bind to the enzyme, binding affinity for the vitamin K hydroquinone is markedly decreased.
  • Without the enzyme gamma-glutamyl carboxylase, vitamin K1 cannot be adequately oxidized resulting in decreased activation of clotting factors II, VII, IX and X.
  • An autosomal recessive mode of inheritance is suspected.
  • These changes can be addressed with the administration of vitamin KVitamin K.

Timecourse

  • Variable dependent on hemodynamic challenge. Some cats may demonstrate spontaneous bleeding, others demonstrate no clinical signs or uncontrolled post-operative hemorrhage.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Littlewood J D, Shaw S C, Coombes L M (1995) Vitamin K-dependent coagulopathy in a British Devon Rex cat.  JSAP 36 (3), 115-118 PubMed.
  • Soute B A, Ulrich M M, Watson A D et al (1992) Congenital deficiency of all vitamin K-dependent blood coagulation factors due to a defective vitamin K-dependent carboxylase in Devon Rex cats. Thromb Haemost 68 (5), 521-525 PubMed.
  • Maddison J E, Watson A D, Eade I G et al (1990) Vitamin K-dependent multifactor coagulopathy in Devon Rex cats. J Am Vet Med Assoc 197 (11), 1495-1497 PubMed.

Other sources of information

  • Little S (2012) The Cat Clinical Medicine and Management. Chapter 25, pp 682.
  • Mischke R (2012) Disorders of secondary haemostasis. Chapter 25 pp 229. In: BSAVA Manual of Canine and Feline Haematology and Transfusion Medicine. 2nd Edn.
  • Tasker S (2006) Clotting and Coagulation Disorders in Cats. Proceedings World Congress WSAVA/FECAVA/CSAVA, pp 364-367.

Organisation(s)


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