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Thrombocytopenia
Aka: Thrombocytopenia, Low Platelets, Low Platelet Count
- Definition
- Decreased Platelet Count below 100k to 150k
- See Also
- Thrombocytopenia Causes
- Platelet Dysfunction
- Purpura
- History
- Family History of Thrombocytopenia
- Consider congenital Thrombocytopenia Causes
- Comorbid conditions
- Liver disease
- Heart Valve Replacement
- Pregnancy
- Gestational Thrombocytopenia
- Preeclampsia with HELLP Syndrome
- Social history
- Alcohol Abuse
- Recent Viral Infection
- Immune Thrombocytopenia (ITP) in children follows acute Viral Infection by days to weeks
- Cytomegalovirus (CMV)
- Epstein Barr Virus (EBV, Mononucleosis)
- Varicella Zoster Virus (VZV, Chicken Pox)
- Parvovirus B19
- HIV Infection
- Hepatitis C
- Tick Bite
- Anaplasmosis
- Babesiosis
- Rocky Mountain Spotted Fever
- Lyme Disease
- Recent international travel (especially tropical)
- Dengue Fever
- Malaria
- Rickettsial Disease
- Medications
- Drug-Induced Thrombocytopenia
- Heparin-Induced Thrombocytopenia
- Chemotherapy
- Radiation Therapy
- Immunizations (MMR, Varicella, H1N1 Influenza Vaccine)
- Transfusion
- Transfusion Reaction
- Infection (Hepatitis C or HIV Infection)
- Symptoms: Clues to Thrombocytopenia Causes
- Abdominal Pain
- HELLP Syndrome (pregnancy)
- Hemolytic Uremic Syndrome (HUS)
- Platelet Sequestration (Splenomegaly)
- Bloody Diarrhea
- Hemolytic Uremic Syndrome (HUS)
- Fever
- Viral Infections (e.g. CMV, EBV, VZV, HIV, HCV, Parvovirus B19)
- Tick Borne Illness ()
- Dengue Fever
- Malaria
- Rickettsial Disease
- Hemolytic Uremic Syndrome (HUS)
- Thrombotic Thrombocytopenic Purpura (TTP)
- Weight loss or Night Sweats
- HIV Infection
- Leukemia
- Myelodysplastic Syndrome
- Exam
- Complete exam to identify underlying cause (see below)
- Deep bleeding (e.g. hemarthrosis) suggest clotting disorder, not Thrombocytopenia
- Signs of bleeding (mucosal and superficial bleeding)
- Petechiae
- Purpura
- Gingival Bleeding
- Gastrointestinal Bleeding
- Urinary tract bleeding
- Signs: Clues to Thrombocytopenia Causes
- Rash
- Viral Exanthems (VZV, Parvovirus B19)
- Rickettsial infections
- Systemic Lupus Erythematosus
- Generalized Lymphadenopathy
- Viral Infections (e.g. CMV, EBV, HIV)
- Systemic Lupus Erythematosus
- Leukemia, Lymphoma and other hematiologic malignancies
- Hepatomegaly
- Chronic Liver Disease
- Leukemia
- Viral Infections (CMV, EBV, HCV)
- Splenomegaly
- Viral Infections (CMV, EBV)
- Neurologic findings
- Thrombotic Thrombocytopenic Purpura (TTP)
- Renal Failure
- Thrombotic Thrombocytopenic Purpura (TTP)
- Hemolytic Uremic Syndrome (HUS)
- Causes
- See Thrombocytopenia Causes
- Categories of Thrombocytopenia
- Decreased Platelet production (e.g. Viral Infection, medications, radiation, B12 Deficiency, marrow infiltration)
- Increased Platelet destruction (e.g. ITP, TTP, HUS, DIC)
- Platelet loss
- Splenic Sequestration
- Labs: Platelet Count Interpretation
- Platelet Count 70,000 to 150,000 per uL
- Mild Thrombocytopenia
- Platelet Count 50,000 to 70,000 per uL
- Asymptomatic Moderate Thrombocytopenia
- Platelet Count 30,000 to 50,000 per uL
- Symptomatic Moderate Thrombocytopenia with excessive bleeding on Traumatic Injury
- Platelet Count 30,000 to 50,000 per uL
- Symptomatic Moderate Thrombocytopenia with excessive bleeding on Traumatic Injury
- Platelet Count 10,000 to 30,000 per uL
- Severe Thrombocytopenia with excessive bleeding with minimal Skin Trauma
- Platelet Count 5,000 to 10,000 per uL
- Severe Thrombocytopenia with risk of spontaneous bleeding, Bruising or Petechiae
- Spontaneous bleeding requiring intervention (e.g. Nasal Packing for Epistaxis) required in 42% of patients
- Platelet Count below 5,000 per uL
- Emergent Thrombocytopenia with high risk of major spontaneous bleeding (e.g. Gastrointestinal Tract, genitourinary tract)
- Labs: Initial Evaluation of Thrombocytopenia
- Complete Blood Count (CBC)
- Basic chemistry panel (chem8)
- Evaluate for associated Renal Failure (e.g. TTP, HUS)
- Expand to comprehensive panel in Hemolysis
- Indirect Bilirubin increased in Hemolysis
- Serum Lactate Dehydrogenase and Haptoglobin increased in HUS and TTP
- Coagulation tests (INR, PTT, Fibrinogen)
- Normal in isolated Thrombocytopenia, ITP, TTP, HUS
- Prolonged in DIC, liver disease, Massive Transfusion and Trauma
- Fibrinogen is decreased in DIC and Trauma
- Peripheral Blood Smear
- See Platelet Morphology
- See Peripheral Blood Smear
- Schistocytes are present in DIC and Microangiopathic Hemolytic Anemia (TTP, HUS), but not ITP
- Consider Parasite stains (Tick Borne Illness, Malaria)
- Hemolysis will raise Indirect Bilirubin
- Platelet Count
- Rule-out Pseudothrombocytopenia
- Review Peripheral Smear to evaluate for clumping (Pseudothrombocytopenia)
- Repeat Platelet Count in non-EDTA Anticoagulant (citrate, blue tube)
- Repeat Platelet Count timing (adjust based on chronicity, stability and bleeding complications)
- Repeat immediately for developing bleeding complications
- Repeat in days to 1 week if Platelet Count <50,000 per uL
- Repeat in 2 weeks if Platelet Count <100,000 per uL
- Repeat in 4 weeks if Platelet Count <150,000 per uL
- Management: General Approach
- Red Flag Findings accompanying Thrombocytopenia indicating Hematology Referral
- Leukopenia or Leukocytosis
- Anemia
- Peripheral Blood Smear abnormalities
- Symptomatic Thrombocytopenia with Bleeding Diathesis, Petechiae, Purpura or Ecchymosis
- Platelet Count <50,000 per uL (or persistently below 100,000 per uL on repeat testing)
- Conditions requiring emergent management
- Heparin Induced Thrombocytopenia (HIT)
- Thrombotic Thrombocytopenic Purpura (TTP)
- Hemolytic Uremic Syndrome (HUS)
- Preeclampsia with HELLP Syndrome
- Disposition home
- Isolated Thrombocytopenia >30,000/mm3 without signs of bleeding in children
- Isolated Thrombocytopenia >30,000 to 50,000/mm3 without signs of bleeding in adults
- No serious cause suspected of Thrombocytopenia (i.e. not HUS, TTP, HIT, DIC)
- Less severe causes include ITP and Drug induced Thrombocytopenia
- Reliable patient or family
- No NSAIDS
- Follow activity restrictions as below
- Management precautions
- Avoid platalet transfusion in Hemolytic Uremic Syndrome, Thrombotic Thrombocytopenic Purpura
- Avoid Corticosteroids in suspected malignancy (until cancer evaluation and staging)
- Management: Activity and Procedure Limitations
- Platelet Count >50,000 per uL
- No limitations to activity or procedures
- Use caution in Collision Sports with Thrombocytopenia
- Most surgical procedures can be perfromed safely at this Platelet Count
- Epidural Anesthesia is safe at 50,000 per uL, but >100,000 per uL is preferred
- Platelet Count >20,000 per uL
- Bone Marrow Biopsy, bronchoscopy and endoscopy can be performed
- Platelet Count <10,000 per uL
- Avoid Collision Sports and other activities with risk of Traumatic Injury
- References
- Merrill and Gillen (2016) Crit Dec Emerg Med 30(3): 3-8
- Gauer (2012) Am Fam Physician 85(6): 612-22 [PubMed]
- George (2000) Lancet 355(9214):1531-9 [PubMed]
- Goldstein (1996) Am Fam Physician 53(3):915-20 [PubMed]
- Rizvi (1999) Curr Opin Hematol 6(5):349-53 [PubMed]