Heparin-induced thrombocytopenia: Difference between revisions
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==Background== | ==Background== | ||
*Despite low plt count pt is actually hypercoagulable | *Despite low plt count pt is actually hypercoagulable; bleeding is unusual | ||
*Pathophysiology | *Pathophysiology | ||
**Pathologic activation / consumption of platelets due to Ab against heparin-plt complex | **Pathologic activation / consumption of platelets due to Ab against heparin-plt complex | ||
**Activated platelets then cause blood clot formation | **Activated platelets then cause blood clot formation | ||
***Platelet count falls b/c plts are bound in clots | ***Platelet count falls b/c plts are bound in clots | ||
**Can be caused by unfrationated or LMWH ( | **Can be caused by unfrationated or LMWH (10x common in the former) | ||
***Occurs in 0.5-5% of pts tx'd w/ heparin | ***Occurs in 0.5-5% of pts tx'd w/ heparin | ||
*Thrombosis occurs in 35-75% of pts; 20-30% die w/in 1 month | *Thrombosis occurs in 35-75% of pts; 20-30% die w/in 1 month | ||
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==Clinical Features== | ==Clinical Features== | ||
*Typical | *Typical | ||
**Symptoms begin 5- | **Symptoms begin 5-10d after initiation of heparin | ||
***>50% decrease in plt count | ***>50% decrease in plt count (median nadir is ~60K; rarely <20K) | ||
***DVT or PE | ***DVT or PE | ||
***Cerebral vein or adrenal vein thrombosis | ***Cerebral vein or adrenal vein thrombosis | ||
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***CVA | ***CVA | ||
***MI | ***MI | ||
***Skin | ***Skin necrosis | ||
*Rapid onset | *Rapid onset | ||
**Symptoms begin within hours of initiation of heparin | **Symptoms begin within hours of initiation of heparin | ||
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==Treatment== | ==Treatment== | ||
#Discontinue all heparin products | #Discontinue all heparin products | ||
#Do not give platelts (may precipitate thrombosis) | |||
#Start anticoagulation | #Start anticoagulation | ||
##Consider lepirudin, argatroban, | ##Consider lepirudin, argatroban, danaparoid, fondaparinux, bivalirudin | ||
##Avoid warfarin | ##Avoid warfarin | ||
Revision as of 07:49, 21 October 2011
Background
- Despite low plt count pt is actually hypercoagulable; bleeding is unusual
- Pathophysiology
- Pathologic activation / consumption of platelets due to Ab against heparin-plt complex
- Activated platelets then cause blood clot formation
- Platelet count falls b/c plts are bound in clots
- Can be caused by unfrationated or LMWH (10x common in the former)
- Occurs in 0.5-5% of pts tx'd w/ heparin
- Thrombosis occurs in 35-75% of pts; 20-30% die w/in 1 month
Clinical Features
- Typical
- Symptoms begin 5-10d after initiation of heparin
- >50% decrease in plt count (median nadir is ~60K; rarely <20K)
- DVT or PE
- Cerebral vein or adrenal vein thrombosis
- Limb arterial occlusion
- CVA
- MI
- Skin necrosis
- Symptoms begin 5-10d after initiation of heparin
- Rapid onset
- Symptoms begin within hours of initiation of heparin
- Due to preexisting circulating antibody from sensitization several weeks earlier
- Sudden drop in plt count
- Thrombosis
- Flushing
- Tachycardia
- Hypotension
- Dyspnea
- Symptoms begin within hours of initiation of heparin
- Delayed onset
- Symptoms begin several days after heparin stopped
- Severe thromboses
Treatment
- Discontinue all heparin products
- Do not give platelts (may precipitate thrombosis)
- Start anticoagulation
- Consider lepirudin, argatroban, danaparoid, fondaparinux, bivalirudin
- Avoid warfarin
Dispostion
- Admit
Source
Tintinalli