Thrombocytopenia

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

Unprovoked gingival bleeding.

Petechiae in a patient with thrombocytopenia.

Petechiae on the tongue in a patient with thrombocytopenia.

Petechiae on the lower leg in a patient with thrombocytopenia.

• 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

Differential Diagnosis of Thrombocytopenia

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

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

Evaluation

Algorithm for the Evaluation of Thrombocytopenia

• Platelet count (CBC)
• Additional workup per clinical presentation

Management

Patient treatments are stratified by the presence or absence 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

• <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