Heparin Induced Thrombocytopenia (HIT)

What is Heparin Induced Thrombocytopenia (HIT)? 

Thrombocytopenia Is one of the common complication of heparin therapy it can present in two ways as shown below. 

What are the two types of Heparin Induced Thrombocytopenia (HIT)? 

Two types of Thrombocytopenia caused by heparin 

Type 1.

 - Most common 

 - Seen in upto 30 %of patients 

 - It's milder form of HIT

 - Occurs after 2-3 of therapy 

 - platelets remains over 50000)/mm³

 - No clinical significance 

Type 2

 - Less common

 - seen in 1-2 %of patients 

 - It presents with signs and symptoms of HIT

 - occurs 7-10 after therapy 

 - It's Immune mediated 

The both types can be summarized as

Thrombocytopenia, a common complication of heparin therapy 

What are the signs and symptoms of Heparin Induced Thrombocytopenia (HIT)? 

Acute systemic reactions may include 

1. chills 

2. Fever 

3. Dyspnea 4. Chest pain, and 

5. Flushing.

Patients with HIT may also present with

Pulmonary embolism and 

Deep venous thrombosis (DVT)

There may be an unusual and unexpected physical findings on patients with HIT (heparin Induced Thrombocytopenia). These may include 

1. Venous limb gangrene

2. Skin lesions at the injection sites

3. Bilateral(B/L) adrenal hemorrhagic infarction 

4. Acute systemic reactions following an intravenous (IV) heparin bolus

What is the treatment of Heparin Induced Thrombocytopenia (HIT)? 

Treatment involves the following 

1.Stop heparin

2.Avoid platelets transfusion as it may increase the thrombogenic effect. It may be tranfused to only patients undergoing invasive procedures with likely risk of bleeding. 

3. Direct thrombin inhibitor (DTI) e.g argatroban (Acova) and Bivalirudin. 

What are Medications that can cause  Thrombocytopenia? 

Other Medications that can cause thrombocytopenia are following:

1. Quinine

2. Quinidine

3. Platelet glycoprotein (gp) IIb/IIIa inhibitors (eg, abciximab,eptifibatide, tirofiban)

4. Sulfonamides (sulfa drugs)

5. Sulfalike drugs

6. Chlorothiazide

7. Chloroquine

8. Rifampicin

9. Gold salts