Thrombocytosis: Difference between revisions

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==Background==
==Background==
Thrombocytosis is generally defined as a platelet count >450,000/microL.  Thrombocytosis can be reactive or autonomous.
*Defined as a platelet count >450,000/microL.


Reactive thrombocytosis (RT) is the most common cause of thrombocytosis, accounting for 85% of cases. RT is a reaction to another process, such as inflammation, infection, cancer, or iron deficiency.  RT rarely causes complications even with extremely elevated platelet counts (>1,000,000/microL).
===Reactive thrombocytosis (RT)===
*Most common cause of thrombocytosis, accounting for 85% of cases.  
*A reaction to another process, such as inflammation, infection, cancer, or iron deficiency.   
*Rarely causes complications even with extremely elevated platelet counts (>1,000,000/microL).


Autonomous thrombocytosis (AT) accounts for 15% of cases.  AT is a primary problem that results from a myeloproliferative or myelodysplastic disorder, such as essential thrombocytopenia or polycythemia vera. Complications, such as bleeding and/or thrombosis, are more likely with AT than with RT so it is clinically important to differentiate reactive thrombocytosis versus autonomous thrombocytosis.  There are no diagnostic studies to differentiate RT versus AT. <ref>Schafer, "Thrombocytosis," N Engl J Med 2004;350:1211-9.</ref>
===Autonomous thrombocytosis (AT)<ref>Schafer, "Thrombocytosis," N Engl J Med 2004;350:1211-9.</ref>===
*Accounts for 15% of cases
*A primary problem that results from [[myeloproliferative disorders]] or [[myelodysplastic syndrome]]s, such as essential [[thrombocytopenia]] or [[polycythemia vera]].  
*Complications, such as bleeding and/or thrombosis, are more likely with AT than with RT so it is clinically important to differentiate reactive thrombocytosis versus autonomous thrombocytosis.   
*There are no diagnostic studies to differentiate RT versus AT.


==Physiology==
==Clinical Features<ref>Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.</ref>==
Platelets are produced by megakaryocytes.  Thrombopoietin (THPO) is the key hormone that regulates platelet production.  THPO binds to receptors on megakaryocytes, leading to differentiation and proliferation.  In disorders that cause AT, there is a dysregulation of THPO, or the THPO-receptor uptake mechanism, leading to increased production of platelets. 
''Generally asymptomatic and found on routine lab testing; complications are typically from AT disorders''
*Thrombosis (leading cause of morbidity and mortality)
**Arteries (more common)
***[[Stroke]], [[TIA]], [[MI]], [[unstable angina]]
**Venous system
***[[DVT]], [[PE]], [[Budd-Chiari syndrome]]
*Serious bleeding (less common)
**Generally in the nasal and bucchal mucosa and the GI tract
*Vasomotor symptoms (due to microvascular disturbances)
**[[Headache]], lightheadedness, [[syncope]], acral [[paresthesia]], atypical [[chest pain]], livedo reticularis, erythromelalgia, and transient [[visual disturbances]]


Thrombopoietin can be elevated in states of acute inflammation or neoplastic disorders, leading to the elevated platelet count seen in RT.  This mechanism is most likely regulated by the acute phase reactant IL-6. <ref>Schafer, "Thrombocytosis," N Engl J Med 2004;350:1211-9.</ref>
==Differential Diagnosis<ref>Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.</ref>==
 
===Reactive thrombocytosis===
==Differential Diagnosis==
* Acute [[hemorrhage|blood loss]]
Reactive thrombocytosis:
* Acute [[hemolytic anemia]]
 
* Iron deficiency [[anemia]]
* Acute blood loss
* Treatment of [[vitamin B12 deficiency]]
* Acute hemolytic anemia
* Rebound effect after [[thrombocytopenia]] treatment
* Iron deficiency anemia
* Treatment of vitamin B12 deficiency
*Rebound effect after thrombocytopenia treatment
* Metastatic cancer
* Metastatic cancer
* Lymphoma
* [[Lymphoma]]
* Rheumatologic disorders
* Rheumatologic disorders
* IBD
* [[IBD]]
* Celiac disease
* Celiac disease
* Kawasaki disease
* [[Kawasaki disease]]
* Nephrotic syndrome
* [[Nephrotic syndrome]]
* POEMS syndrome
* POEMS syndrome
* Thermal burn
* Thermal [[burn]]
* MI
* [[MI]]
* Severe trauma
* Severe [[trauma]]
* Acute pancreatitis
* [[Acute pancreatitis]]
* Post-surgery, especially splenectomy
* Post-surgery, especially [[splenectomy]]
* CABG
* CABG
* TB
* [[TB]]
* Acute bacterial/viral infections
* Acute [[bacterial disease|bacterial]]/[[viruses|viral]] infections
* Asplenia
* [[asplenic patient|Asplenia]]
* Allergic reactions
* [[Allergic reaction]]
* Medication reactions: vincristine, epinephrine, glucocorticoids, IL-1B, ATRA, thrombopoietin, LMWH (uptodate)
* Medication reactions: vincristine, [[epinephrine]], [[glucocorticoids]], IL-1B, ATRA, thrombopoietin, [[LMWH]]<ref>uptodate</ref>
Autonomous thrombocytosis:
* Essential Thrombocytopenia
* Polycythemia Vera
* Mixed myelodysplastic and/or myeloproliferative syndrome


Spurious (false) thrombocytosis:
===Autonomous thrombocytosis===
* [[Essential thrombocytosis]]
* [[Polycythemia vera]]
* Mixed [[myelodysplastic syndrome|myelodysplastic]] and/or [[myeloproliferative disorders|myeloproliferative syndrome]]


===Spurious (false) thrombocytosis===
* Mixed cryoglobulinemia
* Mixed cryoglobulinemia
* Cytoplasmic fragments
* Cytoplasmic fragments
* Bacteremia<ref>Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.</ref>
* [[Bacteremia]]
 
==Clinical Features==
Thrombocytosis is generally asymptomatic and found on routine lab testing.
 
Complications are seen in AT disorders and include thrombosis, bleeding, or vasomotor symptoms.  Thrombotic complications are the leading cause of morbidity and mortality. Thrombosis commonly occurs in arteries (stroke, TIA, MI, unstable angina), but can also occur in the venous system (DVT, PE, Budd-Chiari syndrome).  Serious bleeding is a less common complication and is generally seen in the nasal and bucchal mucosa and the GI tract.
 
Vasomotor symptoms are due to microvascular disturbances and include: headache, lightheadedness, syncope, acral paresthesia, atypical chest pain, livedo reticularis, erythromelalgia, and transient visual disturbances. <ref>Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.</ref>


==Evaluation==
==Evaluation==
General approach:
===Workup===
 
*Labs
Is this reactive thrombocytosis (RT) or autonomous thrombocytosis (AT)?
**CBC, ESR, CRP, iron studies, LDH
*[[CXR]]
*Fecal occult blood test


Is this patient at risk for thrombotic events due to the thrombocytosis?<ref>Tefferi, "Approach to Patient with Thrombocytosis," UpToDate</ref>
===Diagnosis===
*platelet count >450,000/microL.


# CBC.  Compare to previous if possible. 
# H&P looking for causes of RT.
# Labs looking for causes of RT: ESR, CRP, iron studies, blood cultures, LDH.
# Testing looking for causes of RT: CXR, FOBT.
# Consider spurious thrombocytosis.
# If no signs of RT cause, consider AT: blood smear.
==Management==
==Management==
Reactive thrombocytosis: treat underlying disease.  
===Reactive thrombocytosis===
*Treat underlying disease.  


Asymptomatic AT:
===Autonomous thrombocytosis===
# 81mg ASA PO daily.
====Asymptomatic====
# If high risk  for thrombotic event (>60 yrs, history of thrombosis, or known JAK2 mutation), consider 15mg/kg hydroxyurea PO daily.  Consult if available.   
*81mg [[ASA]] PO daily.
# Second line agents include IFN-alpha, anagrelide, and pipobroman.
*If high risk  for thrombotic event (>60 yrs, history of thrombosis, or known JAK2 mutation), consider 15mg/kg [[hydroxyurea]] PO daily.  Consult if available.   
*Second line agents include [[interferon-α]], anagrelide, and pipobroman.


Thrombosis due to AT:
====Thrombosis due to AT====
# Anticoagulation with LMWH.
*Anticoagulation with [[LMWH]].
# 81mg ASA PO daily.
*81mg [[ASA]] PO daily.
# Consult.
*Consult heme/onc
# Consider 3-5 million U IFN alpha SQ daily if <40 years old.  15mg/kg hydroxyurea PO daily if >40 years old.  Goal platelet count <400,000/microL.
*Consider 3-5 million U [[interferon-α]] SQ daily if <40 years old.  15mg/kg [[hydroxyurea]] PO daily if >40 years old.  Goal platelet count <400,000/microL.
# Platelet apheresis if platelet count >800,000/microL.
*Platelet apheresis if platelet count >800,000/microL.


Bleeding due to AT:
====Bleeding due to AT====
# Discontinue antiplatelet medications.
*Discontinue antiplatelet medications.
# Consult.
*Consult.
# Consider 3-5 million U IFN alpha SQ daily if <40 years old.  15mg/kg hydroxyurea PO daily if >40 years old.  Goal platelet count <400,000/microL.<ref>Bleeker, "Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies," Thrombosis. 2011; 2011: 536062. Published online 2011 Jun 8. doi:10.1155/2011/536062.</ref>
*Consider 3-5 million U [[interferon-α]] SQ daily if <40 years old.  15mg/kg [[hydroxyurea]] PO daily if >40 years old.  Goal platelet count <400,000/microL.<ref>Bleeker, "Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies," Thrombosis. 2011; 2011: 536062. Published online 2011 Jun 8. doi:10.1155/2011/536062.</ref>


==Disposition==
==Disposition==
If RT, disposition is based on underlying disorder. 
===Reactive thrombocytosis===
 
*Disposition is based on underlying disorder.   
If asymptomatic AT, consider outpatient treatment with close follow up.   


AT thrombosis or bleeding complications should be admitted for stabilization and further work up.
===Autonomous thrombocytosis===
*If asymptomatic, consider outpatient treatment with close follow up. 
*If thrombosis or bleeding complications, should be admitted for stabilization and further work up.


==External Links==
==External Links==
FOAM: EMDocs, "Thrombocytosis in the ED." [http://www.emdocs.net/thrombocytosis-in-the-ed/]
*[http://www.emdocs.net/thrombocytosis-in-the-ed/ EMDocs, "Thrombocytosis in the ED."]


==References==
==References==
<references>Tefferi, "Approach to the Patient with Thrombocytosis," UpToDate, Jul. 2017.</references>
<references/>
<references>Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.</references>
 
<references>Bleeker, "Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies," Thrombosis. 2011; 2011: 536062. Published online 2011 Jun 8. doi:10.1155/2011/536062.</references>
[[Category:Heme/Onc]]
<references>Schafer, "Thrombocytosis," N Engl J Med 2004;350:1211-9.</references>

Latest revision as of 23:46, 30 September 2019

Background

  • Defined as a platelet count >450,000/microL.

Reactive thrombocytosis (RT)

  • Most common cause of thrombocytosis, accounting for 85% of cases.
  • A reaction to another process, such as inflammation, infection, cancer, or iron deficiency.
  • Rarely causes complications even with extremely elevated platelet counts (>1,000,000/microL).

Autonomous thrombocytosis (AT)[1]

  • Accounts for 15% of cases
  • A primary problem that results from myeloproliferative disorders or myelodysplastic syndromes, such as essential thrombocytopenia or polycythemia vera.
  • Complications, such as bleeding and/or thrombosis, are more likely with AT than with RT so it is clinically important to differentiate reactive thrombocytosis versus autonomous thrombocytosis.
  • There are no diagnostic studies to differentiate RT versus AT.

Clinical Features[2]

Generally asymptomatic and found on routine lab testing; complications are typically from AT disorders

Differential Diagnosis[3]

Reactive thrombocytosis

Autonomous thrombocytosis

Spurious (false) thrombocytosis

  • Mixed cryoglobulinemia
  • Cytoplasmic fragments
  • Bacteremia

Evaluation

Workup

  • Labs
    • CBC, ESR, CRP, iron studies, LDH
  • CXR
  • Fecal occult blood test

Diagnosis

  • platelet count >450,000/microL.

Management

Reactive thrombocytosis

  • Treat underlying disease.

Autonomous thrombocytosis

Asymptomatic

  • 81mg ASA PO daily.
  • If high risk for thrombotic event (>60 yrs, history of thrombosis, or known JAK2 mutation), consider 15mg/kg hydroxyurea PO daily. Consult if available.
  • Second line agents include interferon-α, anagrelide, and pipobroman.

Thrombosis due to AT

  • Anticoagulation with LMWH.
  • 81mg ASA PO daily.
  • Consult heme/onc
  • Consider 3-5 million U interferon-α SQ daily if <40 years old. 15mg/kg hydroxyurea PO daily if >40 years old. Goal platelet count <400,000/microL.
  • Platelet apheresis if platelet count >800,000/microL.

Bleeding due to AT

  • Discontinue antiplatelet medications.
  • Consult.
  • Consider 3-5 million U interferon-α SQ daily if <40 years old. 15mg/kg hydroxyurea PO daily if >40 years old. Goal platelet count <400,000/microL.[5]

Disposition

Reactive thrombocytosis

  • Disposition is based on underlying disorder.

Autonomous thrombocytosis

  • If asymptomatic, consider outpatient treatment with close follow up.
  • If thrombosis or bleeding complications, should be admitted for stabilization and further work up.

External Links

References

  1. ↑ Schafer, "Thrombocytosis," N Engl J Med 2004;350:1211-9.
  2. ↑ Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.
  3. ↑ Tefferi, "Diagnosis and Clinical Manifestations of Essential Thrombocythemia," UpToDate, Jul. 2017.
  4. ↑ uptodate
  5. ↑ Bleeker, "Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies," Thrombosis. 2011; 2011: 536062. Published online 2011 Jun 8. doi:10.1155/2011/536062.
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