Page 890 - Cote clinical veterinary advisor dogs and cats 4th

432 Hemophilias and Other Hereditary Coagulation Factor Deficiencies

diagnostic workup of males with spontaneous Acute General Treatment Recommended Monitoring
or unexpected hemorrhage. • Transfusion to supply hemostatic levels of Confirmation of adequate factor replacement:
VetBooks.ir Differential Diagnosis ○ Use of plasma components reduces risk • Stabilization of hematocrit/plasma protein
• Cessation of active bleeding
the deficient factor (p. 1169)
of intravascular volume overload and red
• Acquired coagulation disorder (e.g., rodenti-
• Resolution of lameness and hematoma
cide intoxication, liver disease, disseminated
intravascular coagulation) cell sensitization while maximizing factor PROGNOSIS & OUTCOME
replacement.
• Thrombocytopenia ○ Fresh-frozen plasma (10-12 mL/kg IV):
• Hereditary platelet function defect or von ■ Appropriate replacement therapy for • Mild to moderate factor deficiencies: good
Willebrand disease deficiencies of fibrinogen and factors quality of life possible; patient may require
• Bleeding caused by tissue injury or infiltrative II through XI occasional transfusion.
disorder ○ Cryoprecipitate (unit dosage varies by • Severe factor deficiencies: fair to poor
• Defect of fibrinolysis supplier): prognosis due to recurrent bleeding and
■ Replacement therapy for fibrinogen dependence on repeated transfusion; acute
Initial Database defects and factor VIII deficiency fatal bleeds may occur.
• Thorough physical exam to define site(s) of ○ Cryopoor plasma or cryosupernatant
hemorrhage. Hemorrhage from more than a (10-12 mL/kg IV): PEARLS & CONSIDERATIONS
single site suggests a hemostatic defect rather ■ Replacement therapy for factors II, VII,
than blood loss from vessel injury. IX, X, and XI deficiencies Comments
• Baseline hematocrit and plasma protein • Replacement of red cells for severe blood-loss • Hemophilia A (factor VIII deficiency) is the
• Platelet count: usually normal unless pro- anemia primary rule out for abnormal bleeding in
longed hemorrhage (platelet loss) ○ Fresh whole blood (12-20 mL/kg) or young male dogs and cats.
• Point-of-care coagulation screening tests (*, packed red cells (6-12 mL/kg) • Feline factor XII deficiency does not cause
markedly abnormal): clinical bleeding; typically identified in
○ ACT: prolonged (factors I, II, VIII, IX, Chronic Treatment workup for an acquired disease process.
X, XI, and XII deficiencies) or normal • Intermittent transfusion as needed to control • Platelet dysfunction is usually associated with
(factor VII deficiency) hemorrhagic events petechiae or ecchymoses, while clotting factor
○ aPTT: prolonged (factors I, II, VIII, IX, • Preoperative transfusion to prevent abnormal dysfunction is associated with bleeding into
X, XI*, and XII* deficiencies) or normal bleeding spaces such as the abdomen, thorax, and
(factor VII deficiency) • Avoidance of unnecessary invasive procedures joints.
○ Prothrombin time (PT): prolonged (factors
I, II, VII, and X deficiencies) or normal Behavior/Exercise Prevention
(factors VIII, IX, XI, and XII deficiencies) • Strenuous activity should be avoided to help • Factor-deficient dogs and cats should never
• Laboratory coagulation panel limit intraarticular hemorrhage. be used for breeding.
○ aPTT, PT: as above • Hemophilic cats should remain indoors; dogs • Familial testing is indicated to identify
○ Fibrinogen: low (factor I deficiency), should be supervised when outdoors. asymptomatic carriers before breeding.
normal for others • Owners must balance quality of life with
○ Thrombin clotting time: prolonged (factor reasonable exercise restriction. Technician Tips
I deficiency), normal for others • A blue-top tube (sodium citrate anticoagu-
Drug Interactions lant) must be adequately filled for coagulation
Advanced or Confirmatory Testing Avoid drugs with anticoagulant or antiplatelet screening tests.
Definitive diagnosis based on identifying low effects (e.g., nonsteroidal antiinflammatory • Avoid jugular venipuncture if abnormal
levels of specific coagulation factors: drugs [NSAIDs], clopidogrel, sulfonamides, hemostasis is apparent.
• Clottable fibrinogen (factor I) heparin, warfarin, plasma expanders, estrogens,
• Coagulant activity assays (factors II through cytotoxic drugs). Client Education
XII) Definitive diagnosis aids in determining prog-
Possible Complications nosis, selecting appropriate transfusion therapy,
TREATMENT • Red cell sensitization causing transfusion and providing genetic counseling.
reactions
Treatment Overview ○ Transfuse plasma components when SUGGESTED READING
Patients with confirmed factor deficiencies but possible. Cuoto CG: Disorders of hemostasis. In Cuoto CG,
without clinical signs should receive a prophy- ○ Feline transfusion: donor and recipient et al, editors: Small animal internal medicine, ed
lactic transfusion before surgery. Patients with must be type matched for any transfusion. 5, St. Louis, 2014, Mosby, pp 1245-1247.
confirmed factor deficiencies who are actively ○ Canine transfusion: perform cross- AUTHOR: Marjory B. Brooks, DVM, DACVIM
bleeding may require repeated transfusions and, match before second and subsequent EDITOR: Jonathan E. Fogle, DVM, PhD, DACVIM
rarely, withdrawal of blood if compromising transfusions.
vital functions (e.g., large-volume pleural effu- • Development of inhibitory anti-factor
sion). In both categories, avoid unnecessary antibodies (rare)
surgery or invasive procedures.

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