Thrombocytopenia

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Background

  • Thrombocytopenia is defined as platelets of less than 150 x 103/mcL. Symptoms such as bruising and petechiae usually occur at counts at 50 x 103/mcL and between 5-10x 103/mcL there is a high risk of spontaneous bleeding.

Clinical Features

  • Nonpalpable petechiae/purpura
  • Mucosal bleeding (gingival, epistaxis)
  • Menorrhagia, hemoptysis, hematuria, hematochezia
  • Deep tissue/joint bleeding is less common (more likely due to coagulopathies)

Differential Diagnosis

Thrombocytopenia

Decreased production

  • Marrow infiltration (tumor or infection)
  • Viral infections (rubella, HIV)
  • Marrow Suppression (commonly chemotherapy or radiation)
  • Congentital thrombocytopenia
    • Fanconi anemia
    • Alport syndrome
    • Bernand Soulier
  • Vitamin B12 and/or folate deficiency

Increased platelet destruction or use

Drug Induced

  • sulfa antibiotics, ETOH, ASA, thiazides/furosemide

Comparision by Etiology

ITP TTP HUS HIT DIC
↓ PLT Yes Yes Yes Yes Yes
↑PT/INR No No No +/- Yes
MAHA No Yes Yes No No
↓ Fibrinogen No No No No Yes
Ok to give PLT Yes No No No Yes

Coagulopathy

Platelet Related

Factor Related

Evaluation

  • Platelet count (CBC)

Management

Patient treatments are stratified by the presence or abscess of bleeding and in the non bleeding patient by the platelet number and the presumed cause of the thrombocytopenia

Platelet Transfusion Thresholds

most if not all of the following thresholds are based on weak recommendations with low quality evidence[1]

  • <50K if planned lumbar puncture or neurosurgical procedure
  • <20K if planned for central venous catheter placement (preference toward compressible site), or febrile patient
  • <10K in asymptomatic patients (unless due to ITP, TTP, or HIT)

There are no firm recommendations for transfusion thresholds in acute traumatic bleeding but many providers will opt for a goal of 100K, especially if there is evidence of ICH

Transfusion contraindications

  • TTP, DIC, HIT

Pediatrics

  • 1 unit of platelets per 5kg body weight raises count by 50k

Disposition

See Also

References

  1. ↑ Kaufman, R. et al. Platelet Transfusion: A Clinical Practice Guideline From the AABB. Annals of Internal Medicine. 2015. Vol 162. No. 3 205-214 Full Text