IMTP Flashcards

1
Q

What occurs during primary hemostasis?

A

Formation of a platelet plug via PLT adhesion (vWF), activation, and aggregation

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2
Q

What occurs during secondary hemostasis?

A

Coagulation factors are activated to produce end product of Fibrin that stabilizes the platelet plug formed during primary hemostasis

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3
Q

What coagulation factors are measured using PT?

A

Factor 7 (extrinsic pathway)

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4
Q

What coagulation factors are measured using aPTT?

A

12, 11, 9, 8 (intrinsic pathway)

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5
Q

What clinical signs can be seen if there is an issue with primary hemostasis?

A
  • Petechia
  • Ecchymosis
  • Oozing blood from mucosal sites (mouth, eyes, GI tract, nose, bladder)
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6
Q

What clinical signs can be seen if there is an issue with secondary hemostasis?

A
  • Bleeding into a body cavity
  • Large SQ hematomas
  • Larger scale blood loss that isn’t normally seen with primary hemostatic disorders
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7
Q

What diagnostics are used to assess primary hemostasis?

A
  • Manual blood smear to assess PLT count and R/O clumping
  • Low or normal PLTs on CBC
  • BMBT to assess PLT function (will be increased)
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8
Q

What does an increased BMBT indicate?

A
  • Primary hemostatic disorder
  • Either a problem with PLT function or PLT numbers
  • Consistent with marked thrombocytopenia
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9
Q

List the most common differentials for thrombocytopenia

A
  • IMTP (severe thrombocytopenia)
  • Bone marrow disease (neoplasia, drugs)
  • Pseudothrombocytopenia (Cavaliers, Greyhounds)
  • Sequestration from splenomegaly
  • DIC (consumption)
  • Bleeding / Blood loss (less likely to cause severe thrombocytopenia)
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10
Q

What drugs are known to result in a primary hemostatic disorder causing thrombocytopenia?

A
  • Chloramphenicol
  • Estrogen

(Bone marrow toxicity resulting in thrombocytopenia / decreased PLT numbers)

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11
Q

List causes of secondary IMTP

A
  • Rickettsial diseases (RMSF, E.canis)
  • Vaccines/ Medications given within the last 30 days
  • Sytemic lupus erythematosus
  • Neoplasias (Lymphoma, HSA, OSA)

(similar causes as IMHA)

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12
Q

What is the drug treatment of choice for patients with IMTP?

A
  • Prednisone (glucocorticoids) most frequently used
  • Can use adjunct Vincristine, IVIG, Mycophenolate, Cyclophosphamide
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13
Q

What should the PLT count be to consider a patient stable enough to be released from hospital?

A

PLT count > 15-20k (unlikely to need blood products or bleed out)

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14
Q

When is a blood transfusion indicated for patients with thrombocytopenia?

A
  • If concurrent anemia with PCV < 15%
  • Transfuse with WHOLE BLOOD to maintain PCV while awaiting plt count increase
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15
Q

How is vincristine used in the treatment of IMTP?

A
  • Stimulates premature release of PLTs from bone marrow
  • Decreases hospitalization time
  • Not 1st line for IMTP!! Pred is
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16
Q

What is IVIG therapy?

A
  • Human immunoglobulins that temporarily block Fc receptors
  • Used for IMTP to increase PLT count

NB: Human product so can cause severe anaphylaxis!!

17
Q

What is the prognosis of patients presenting with IMTP?

A
  • Good prognosis if short term disease diagnosed within 1 month
18
Q

What diagnostic test findings are consistent with Von Willebrand disease?

A
  • Increased BMBT
  • PLT count usually normal
  • PTT / ACT usually normal
19
Q

What are congenital causes of primary hemostatic disorders?

A
  • vWD
  • Basset hound thrombopathy
20
Q

Is PT or PTT prolonged first?

A

PT bc Factor 7 has the shortest half life

21
Q

What diagnostic test findings can be present in patients with Warfarin toxicity?

A
  • Causes Vit K deficiency (Lack of factors 2,7,9,10)
  • Normal PLTs (can be inc due to reactive thrombocytosis)
  • Increased PT and aPTT
  • Increased ACT
  • Normal BMBT
  • Regenerative anemia
22
Q

What CS do patients with Warfarin toxicity present with?

A
  • Massive bleeding / hemorrhage
  • Anemia, weak, palor
  • Hypovolemia, shock
  • Dyspnea if bleeding into thoracic cavity
  • Lameness if bleeding into joint cavities
  • Neuro signs if brain bleed

(Secondary hemostatic disorder / lack of clotting factors)

23
Q

What is the most common cause of SEVERE thrombocytopenia in dogs?

A
  • IMTP
24
Q

What is Evans syndrome?

A

IMHA and IMTP together

25
Q

What PLT range would be concerning for risk of bleeding?

A

< 30k - 50k

26
Q

You run a CBC on a 5 year old king Charles spaniel presenting for wellness check and see evidence of thrombocytopenia. What is the next best diagnostic test to perform?

A
  • Do peripheral blood smear!!
  • Have to R/O inherited macrothrombocytosis in Cav
  • R/O PLT clumping!!
27
Q

What are common causes of thrombocytopenia due to consumption in cats?

A
  • FIP
  • Rickettsial diseases
  • DIC
28
Q

True or False: Hemorrhage can result in severe thrombocytopenia

A

False …. Exception: acute SEVERE hemorrhage

Otherwise hemorrhage / blood loss usually causes a mild thrombocytopenia

29
Q

What neoplasias can cause secondary IMTP?

A
  • High grade lymphoma
  • HSA
  • OSA

(can cause IMHA too)