HLS Pathology 13 : Platelets disorders

(T/F)

According to relationship between platelet count and bleeding , levels above 60000 /µl will not cause bleeding under normal conditions

True

(T/F)

According to relationship between platelet count and bleeding , Levels between 20000 and 60000 /µl may cause bleeding

True

According to relationship between platelet count and bleeding , Levels around……can lead to fatal CNS or GI hemorrhage.

5000 /µl

Levels below 20000 /µl will cause?

-Petechiae

-mucosal bleeding

-Post-operative bleeding

-CNS bleeding.

Immune thrombocytopenia (ITP) Pathogenesis

autoantibodies target the platelets , The antigenic target is platelet GP IIb/IIIa complex

(T/F)

Acute ITP (Idiopathic/Childhood) preceded by infection or vaccination while the chronic not

True

Initial Platelet .count in Acute ITP

<20,000

(T/F)

Acute ITP (Idiopathic/Childhood) usually Affects children while the chronic have high incidence in women of child bearing age (20-50).

true

in chronic ITP

Platelets lifespan….

Megakaryocytes….

Hb and WBCs….

-Platelets lifespan reduced to hours

-Megakaryocytes increased

-Hb and WBCs normal

functional deficiency of a plasma protease (designated ADAMTS13) can cause…

Thrombotic thrombocytopenic purpura (TTP)

Diagnosis methods of TTP

➢CBC with platelet count

➢ peripheral blood smear

➢coagulation studies(Normal PT, PTT, D-Dimer but elevated BT). same as the HUS

➢Signs of hemolysis: Increase LDH, Increase indirect bilirubin Decrease Haptoglobin

➢ BUN and creatinine.

➢Measuring ADAMTS13 activity level.

the most common cause of acute kidney injury in children

Hemolytic Uremic Syndrome (HUS)

……clinical syndrome characterized by progressive kidney failure that is associated with microangiopathic (nonimmune, Coombs-negative) hemolytic anemia and thrombocytopenia.

Hemolytic Uremic Syndrome (HUS)

primary event in the pathogenesis of hemolytic-uremic syndrome (HUS) ?

Damage to endothelial cells by E. coli O157:H7 toxin

Hemolytic Uremic Syndrome (HUS) and TTP differences

- HUS More seen in pediatric population

- HUS occur After viral/bacterial infection

- Pathologic thrombi almost always limited to glomerular capillaries