CHRONIC ITP

By DR Falak abro

• chronic ITP persists for more than 6-12 months.

• Chronic ITP has more insidious onset with easy bruising and petechiae

•Age 8-14 years.

• male : female ratio is 1:2

PATHOPHYSIOLOGY

• Increased platelet destruction .

• Spleen is key organ in Pathophysiology

.platelet autoantibodies formed in white pulp

. Macrophages in red pulp destroy immunoglobulin coated platelets.

PATHOPHYSIOLOGY

•Autoantibody coated platelets induce Fc receptor-mediated phagocytosis by mononuclear macrophages

Clinical Signs and symptoms

*Bruise

Petechiae

PurPura

Gingival bleeding

Epistaxsis

INVESTIGATION

PERIPHERAL BLOOD FILM

• ITP with low platelet count usually (<100,000 usually) with normal hemoglobin and WBC count

• thrombocytopenia with platelet count <20 x 109/L is common and platelet size may be normal or increased

Bone Marrow Examination

•The bone marrow in patients with ITP contains normal or increased number of megakaryocytes indicates that :

a: plateletes production is normal

b: thrombocytpenia is due to increased platelet destruction.

TREATMENT

• Wait and Watch if platelets are below 50,000 or there is no signs of bleeding.

INTRAVENOUS IMMUNOGLOBULINS

•Mechanism:

blocking FC receptors of RE (reticuloendothelial) phagocytes.

• preventing them from binding and destroying IgG antibody-coated platelets.

LNH PHARMACY

1 vial= 250 mgPrice= approx Rs: 1500

Dose : safe dose is 400mg/kg/day using 5 days continuously or 1g/kg/day for 2 days.

Merits: IVIG is preferable to steroids because it causes faster elevation of platelete count greater than 20,000 within 24 hours.

Demerits :• Its expensive

• Long infusion time of 6-8 hours

• Headache

• vomiting

Corticosteroids:

Mechanism

• inhibit platelet destruction.

•Rapid action that reduces RE destruction of antibody coated platelet.

Dose:•Oral prednisone 1-2mg/kg/day for two weeks then tapered over third week

• In chronic ITP with recurrent bleeding intravenous methyl predinisolone20-30mg/kg/day for 3 days can be given.

Intravenous Anti D therapy :MECHANISM:• Specific red blood cell antibodies coat red blood cells, which are taken by RE system in place of antibody coated platelets.

•Anti Rh-D immunoglobulin produces mild hemolytic anemia that saturates Fc receptors of phagocytic elements of RE system.

•Dose I/V 50ug -75ug/kg for two days platelet rise within 48 hours to 72 hours.

•Merits: Lower side effects than IVIG doesnot cause headach or vomiting

•Demerit: causes hemolysis.

LNH PHARMACY

1 vial= 300 ugPrice = RS: 5500

SPLEENECTOMY:

•Indicated in chronic, symptomatic ITP when other options fail.

•About 64-88% of patient with chronic Itp achieve complete remission.

It is done because It removes:• primary site of platelete destruction and

site of antiplatelete-antibody production

RITUXIMAB:MECHANISM:

• it is monoclonal antibody which depletes B-cells by binding to the CD-20 antigen surface •Therapy effect remains for 6-12 months as it prevents activity of autoreactive cells specially against gp-IIb/IIIa.

Dose : 375mg/m2 per dose weekly for 4 weeks.

Price : 100mg vial approx RS: 17000 500mg vial approx RS: 85000

Time to respond therapy : 1-7 weeks

Side-effects: fever, chills, allergy reactions which can be prevented by slow infusion and premedication with antihistamine or steroids.

(Thrombopoeitin) TPO receptor agonists

•Mechanism of action

•Endogenous TPO made in liver which regulates platelet production by increasing the number and maturation of bone marrow megakaryocytes.

•2 TPO receptor agonists : a: romiplostim with dose 1-10ug/kg/dose subcutanously weekly.

b: Eltrombopag with dose is 50mg orally.

•ROMIPLOSTIM is a subcutaneous thrombopoiesis stimulating FC-peptide fusion protein.

•ELTROMBOPAG is orally active non peptide agonist, it acts by stimulating platelet production.

Side effects

• Romiplostim : headache, phyrangitis, fatigue

•Eltrombopag : nausea and vomiting, hepatic toxicity

THANKYOU…