Thrombocytopenia

Background

Thrombocytopenia is best grouped into a few main categories. The following lists helps organize workup and differential.

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)
• Congenital thrombocytopenia
  • Fanconi anemia
  • Alport syndrome
  • Bernand Soulier
• Vitamin B12 and/or folate deficiency

Increased platelet destruction or use

• Idiopathic thrombocytopenic purpura
• Thrombotic Thrombocytopenic Purpura (TTP)
• Hemolytic Uremic Syndrome (HUS)
• Disseminated Intravascular Coagulation (DIC)
• Viral infections (HIV, mumps, varicella, EBV)
• Drugs (heparin, protamine)
• Postransfusion or Posttransplantation
• Autoimmune destruction (SLE or Sarcoidosis)
• Mechanical destruction
  • Artificial valves
  • ECMO
• HELLP syndrome
• Excessive hemorrhage
• Hemodialysis, extracorporeal circulation
• Splenic Sequestration
  • Occurs in Sickle cell disease and Cirrhosis

Drug Induced

• sulfa antibiotics, ETOH, ASA, thiazide diuretics/furosemide

Comparison by Etiology

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

Bleeding Specific Differential Diagnosis

Coagulopathy

Platelet Related

• Too few
  • Thrombocytopenia
• Nonfunctional
  • Aspirin
  • Von Willebrand disease

Factor Related

• Acquired (Drug Related)
  • Warfarin (Coumadin)
  • Unfractionated heparin
  • Low molecular weight heparin (i.e. enoxaparin (Lovenox), dalteparin)
  • Factor Xa Inhibitors (e.g. rivaroxaban, apixaban, fondaparinux, edoxaban)
  • Direct thrombin inhibitors (e.g. dabigatran, argatroban, bivalirudin)
• Illness induced
  • Vitamin K deficiency
  • Disseminated Intravascular Coagulation (DIC)
  • Liver disease induced coagulopathy
  • Uremic bleeding syndrome
• Genetic
  • Hemophilia
  • Factor VIII inhibitor
  • Lupus anticoagulant

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