Acquired disorders of haemostasis. Flashcards Preview

Clinical Pathology > Acquired disorders of haemostasis. > Flashcards

Flashcards in Acquired disorders of haemostasis. Deck (28):
1

how can you determine whether or not the acquired bleeding disorder is due to deficiency in the inhibitor.

APTT (measures the activity of the intrinsic and common pathways of coagulation)
Do one test on patients blood and a repeat test on patients blood mixed with normal blood.
If the repeat test shows significant correction then the deficiency is due to a lack of inhibitor.

2

acquirered bleeding disorders include

vitamin K deficiency
liver disease
massive transfusion syndrome
DIC
iatrogenic
acquired inhibitors.

3

how are patients with the possibility of a acquired bleeding disorder assessed

• Clinical history
• Date of onset, previous history of bleeding episodes and clinical pattern
• Response to challenges e.g. surgery, dental extraction
• For young children: bleeding from umbilical stump, vaccination, and circumcision.
• Requirement for medical/ surgical intervention
• Other systemic illness and drug history
• Family history
• Clinical examination: pattern of any bruising or other evidence of haemorrhagic signs, signs of underlying disease, joints, muscles and skin.

4

how can portal hypertension effect the blood plasma level.

portal hypertension causes congestion in the spleen and as more than 1/3 platelet are found in the spleen you will get less in the plasma.

5

which coagulation cascade factors are vitamin K dependent

2,7,9,10

6

which organ synthesises all the clotting factors

liver

7

when vitamin K is used as a co-factor what does is become

VKOR- vitamin K epoxide

8

what enzyme converts Vitamin K to VKOR

gamma glutamyl carboxylase

9

which enzyme converts VKOR to vitamin K

vitamin K reducatse

10

which enzyme does wharfing work against

vitamin K reducatse.

11

what are the main causes of vitamin K deficenccy

prolonged nutritional deficiency.
Obstructive jaundice- cannot get bile salts in gut so fat uptake is reduced which reduced vitamin K uptake

12

what major risk do patients with liver disease have when undergoing surgery

bleeding
liver typically produces the clotting factors.

13

what factors cause impaired haemostats is in liver disease

thrombocytopenia
platelet dysfunction
reduced plasma concentration
delayed fibrin monomer polymeriation
excessive plasmin activity.

14

which is the only clotting factor whose amount is not reduced in liver disease

FVIII.

15

define massive transfusion

Transfusion of a volume equal to the patient’s total blood volume in less than 24 hours or
50% blood volume loss within 3 hours

16

what causes the haemostatic abnormalities in a massive transfusion

dilutional depletion of platelets and coagulation factors (mainly V and VIII)
DIC
underlying disease, eg liver or renal drug treatment or surgery
Citrate toxicity- hypothermia
hypocalcaemia.

17

what is most likely cause of DIC

sepsis of gram -ve organism
causes damage and tissue factor exposure

18

what are the consequences of DIC

consumption of clotting factors and platelets, microvascular (thrombosis), tissue ischaema and organ damage.
Activation of fibrinolysis microangiopathic haemolysis.

19

Causes of acute DIC

sepsis
obstetric problems
trauma/tissue necrosis
acute intravascular haemolysis
fulminant liver disease.

20

laboratory tests for DIC

FBC
coagulation screen- PT, APTT, TCT, Fibrinogen concentration, FDP or D-dimer.

21

Is a coagulation screen for DIC do the tests have shortened or prolonged test results

prolonged.

22

Is the D dimer elevated or suppressed in DIC

elevated.

23

Treatment for DIC

treat the underlying cause
supportive treatment- maintain tissue perfusion, co-ordinate treatment with fresh frozen plasma
and provide folic acid and vitamin K supplements.

24

define prothrombin ratio

patient’s prothrombin time/ mean normal prothrombin time.

25

what is ISI

Correction factor to account for sensitivity of thromboplastin compared with the international reference preparation

26

drugs which potentiate warfarin affect include

• Cimetidine
• Ampicillin (oral)
• Amiodarone
• NSAID’s
• Sulphinpyrazone
• Chlorpromazine
• Cotrimoxazole
• Sulphonylureas
• Erythromycin
• Corticosteroids
• Cephlosporins

27

drugs which antagonise the warfarin effect.

• Cholestyramine
• Spironolactone
• Rifampicin
• Carbamazepine
• Vitamin K

28

what is a side effect of too much oral anticoagulant

reduced platelet levels.