Categories: Hematology/Oncology

Heparin-Induced Thrombocytopenia (HIT): Type 1 vs. Type 2

Type 1: Heparin directly causes platelets to aggregate (non-immune). Occurs within 48hrs after initiating heparin; mild, transient and no treatment needed.

Type 2: Heparin induces auto-immune mediated response (antibodies formed against heparin bound to platelet factor 4 (PF4). Characterized by the  4T score. (If the score is 0-3, HIT is unlikely, <5%)  

NOTE: HIT is generally not marked by bleeding; instead an increased risk of venous thromboembolism!

REFERENCES

  1. Warkentin, T. E. (2003), Heparin-induced thrombocytopenia: pathogenesis and management. British Journal of Haematology, 121: 535–555. doi:10.1046/j.1365-2141.2003.04334.x
  2. Warkentin TE, Heddle NM (March 2003). “Laboratory diagnosis of immune heparin-induced thrombocytopenia”. Curr Hematol Rep. 2 (2): 148–57.
  3. Greinacher, A., Michels, I., Schafer, M., Kiefel, V. & Mueller- Eckhardt, C. (1992) Heparin-associated thrombocytopenia in a patient treated with polysulphated chondroitin sulphate: evidence for immunological crossreactivity between heparin and polysulphated glycosaminoglycan. British Journal of Haematology, 81, 252–254.
Get Medical Pearls directly to your inbox every week!
Weekly posts with high yield medical knowledge, directly to your mailbox!
Dr. C Humphreys

Internal Medicine

Share
Published by
Dr. C Humphreys

Recent Posts

Nocturia and OSA: Mechanism

Nocturia is a common symptom associated with obstructive sleep apnea. [1] Img Cred: Am J…

5 months ago

ASD vs. VSD Murmur Difference

ASD (Atrial Septal Defect) Wide, Fixed split S2 (in contrast to the normal variation in…

5 months ago

Mechanism of a Mixed Apnea

Mixed apneas are characterized by absent respiratory effort and airflow in the first section of…

1 year ago

How Does Hypothyroidism Cause Hypoventilation?

Although rare, the differential diagnosis of hypoventilation and hypercapnia respiratory failure includes hypothyroidism. It is…

1 year ago

Why is Pro-BNP/ BNP lower in Obesity?

B-type natriuretic peptide (BNP) is a hormone created in response to cardiac wall stretch due…

2 years ago

What is Peribronchovascular Distribution on CT imaging?

A common finding described on computed tomography (CT) imaging. A disease with a peribronchovascular distribution…

2 years ago

This website uses cookies.