DLA(4)- Bleeding Disorders

Question 1

what are the general causes of bleeding disorders

Answer 1

• inc small BV fragility
• platelet deficiency or dysfunction
• coagulation abnormality

Question 2

describe the difference in bleeding between platelet defects and coagulation abnormalities

Answer 2

Platelet: superficial (skin, mucosa), mild bleeding

Coagulation: deep and severe bleeding

Question 3

list the main tests to evaluate hemostasis

Answer 3

1) platelet count: normal is 150,000-400,000/mL
2) bleeding time: platelet function evaluation

3) PT: extrinsic coagulation (and common)
4) aPTT: intrinsic coagulation (and common)

5) thrombin time: fibrinogen function evaluation

Question 4

describe the platelet disorder types

Answer 4

• abnormal platelet function –> prolonged bleeding time, normal platelet count
• thrombocytopenia (dec platelets) –> prolonged bleeding time, low platelet count

Question 5

list the Congenital Platelet Function Abnormality conditions

Answer 5

• Glanzmann thrombasthenia (defective GpIIb/IIIa)
• Bernard-Soulier syndrome (defective GpI)
• Wiskott-Aldrich syndrome
• Storage pool disease

Question 6

list the acquired platelet function abnormality conditions

Answer 6

• drug causation: ASA/NSAIDs

- uremia

Question 7

describe the general causes of Thrombocytopenia

Answer 7

• dec production
• dec platelet survival
• splenic sequestration
• dilutional thrombocytopenia

Question 8

thrombocytopenia due to decreased platelet survival is the result of either (1) or (2) destruction

Answer 8

Immune destruction

Non-immune destruction

Question 9

ITP = (1) , and is caused by (2).

• (3) describe acute ITP
• (4) describe chronic ITP

Answer 9

1- immune thrombocytopeni purpura
2- primary or secondary to autoimmune disorder (SLE) [Igs against GpIIb/IIa or GpI)

3- self-limiting, abrupt onset, mostly viral infections in children

4- (more common) insidious onset, women 20-40 y/o, skin +/- mucosal bleeding +/-splenomegaly (rarely spontaneous resolves)`

Question 10

list and describe the Nonimmune Thrombocytopenias

Answer 10

TTP (thrombotic thrombocytopenic purpura): fever, thrombocytopenia, microangiopathic hemolytic anemia, transient neurological deficits, renal failure

HUS (hemolytic uremic syndrome): clinically like TTP w/o neurological deficits and more pronounced renal failure

Question 11

(1) is the most common bleeding disorder where (1) usually functions to (2), therefore their are deficits in (bleeding (platelets) / coagulation (factors)).

Answer 11

1- VWD (von Willebrand disease)

2:

i) adhesion of platelets to subendothelial layer
ii) factor VIII carrier (inc 1/2 life)

3: both, but only platelet dysfunction is noted clinically (elevated bleeding time, normal coagulation)

Question 12

VWD types

Answer 12

1- 70%, reduced VWF, mild
3- reduced VWF, severe

2- 25%, defective VWF binding/interactions, mild to moderate

Question 13

VWD Tx

Answer 13

n/a if mild / moderate

-factor replacement in severe cases

Question 14

Hemophilia A aka (1) is inherited in (2) fashion. (3) is the key lab sign, (4) is the main treatment.

Answer 14

1- factor VIII deficiency
2- X-linked
3- prolonged aPTT
4- recombinant factor VII infusions

Sx: prolonged bleeding and inc hemorrhages

Question 15

define DIC

Answer 15

disseminated intravascular coagulation: acute to chronic thrombotic hemorrhagic syndrome secondary to underlying disease