Thrombocytopenia

Background

• Spontaneous bleeding concerning when platelet count <20K

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)

Causes

• Decreased production
  • Marrow infiltration (tumor or infection)
  • Viral infections (rubella, HIV)
  • Drugs
    • Heparin Induced Thrombocytopenia
    • sulfa abx, ETOH, ASA, thiazides/furosemide
  • Radiation
  • Vitamin B12 and/or folate deficiency
• Increased platelet destruction
  • ITP
  • TTP
  • HUS
  • DIC
  • Viral infections (HIV, mumps, varicella, EBV)
  • Drugs (heparin, protamine)
• Platelet loss
  • Excessive hemorrhage
  • Hemodialysis, extracorporeal circulation
• Splenic sequestration
  • Sickle cell disease, cirrhosis

Diagnosis

• Platelet count (CBC)

Treatment

Platelet Transfusion Thresholds

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

• <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

See Also

• Coagulopathy (Main)
• Platelet Transfusion

Source

Tintinalli