Immune-mediated thrombocytopenic purpura: Difference between revisions

Latest revision as of 23:27, 21 September 2020

Background

Acquired autoimmune bleeding disorder characterized by autoimmune autobody-mediated destruction of platelets

Etiology

Primary
Secondary
- Infection
- Inflammatory/Autoimmune
  - Antiphospholipid antibody syndrome
  - Autoimmune thrombocytopenia (Evans syndrome)
- Congenital: common variable immune deficiency
- Neoplasm: lymphoproliferative disorder
- Medications

Investigations

CBC
- Mean platelet volume can suggest high platelet turnover
Peripheral blood film
HIV and HCV testing
Additional
- Abdo ultrasound for splenomegaly and liver disease
- Rh status
- DAT for Evan's syndrome
- Quantitative immunoglobulins
- Hep B testing
- H. pylori, if at risk
- Antiphospholipid antibodies
- ANA, anti-dsDNA
- Thyroid tests
- vWF testing (for type 2B vWD)
- Bone marrow biopsy

Management

Acute management

Only needs treatment if platelets lower than 30 or if bleeding
First-line:
- Steroids
  - Prednisone 1-2mg/kg/day x3weeks then taper (70-80% response but high relapses over next 10 years)
  - Dexamethasone 40mg/d po x4days ever 2-4 weeks, repeated for 3-6 cycles (90% response)
- IVIg 1-2g/kg x1-2 days, if refractory to steroids or requires rapid treatment
- Anti-D if Rh positive and has a spleen
Second-line:
- Splenectomy
  - Ensure vaccinated for Hib, Strep pneumo, and N. meningitidis
- Rituximab
- Thrombopoeitin agonists: eltrombopag or romiplostim
- Immunosuppressive therapies: azathioprine, cyclosporin A, cyclophosphomide, danazol, dapsone, mycofenolate mofetil, vina alkaloids
Third-line:
- Almtuzumab, chemotherapy, stem cell transplant
For life-threatening bleed:
- IVIG 1g/kg, repeated once more if platelets remain below 50 the next day
- Pulse steroids: methylprednisolone 30mg/kg IV daily x2-3 days)
- Tranexamic acid 1G IV q6h
- Platelet transfusion
- Emergency splenectomy
- Last-ditch: recombinant factor VIIa 90mcg/kg IV q2h
  - High risk for clotting

@@ Line 1: / Line 1: @@
-== Definition ==
+==Background==
-* Acquired autoimmune bleeding disorder characterized by autoimmune autobody-mediated destruction of platelets
+*Acquired autoimmune bleeding disorder characterized by autoimmune autobody-mediated destruction of platelets
+===Etiology===
-== Differential Diagnosis ==
-* Primary
+*Primary
-* Secondary
+*Secondary
-** Infection
+**Infection
-*** HIV
+***[[HIV]]
-*** Hepatitis C
+***[[Hepatitis C virus]]
-*** CMV
+***[[CMV]]
-*** VZV
+***[[VZV]]
-*** H. pylori
+***[[Helicobacter pylori]]
-** Inflammatory/Autoimmune
+**Inflammatory/Autoimmune
-*** Antiphospholipid syndrome
+***[[Antiphospholipid antibody syndrome]]
-*** Autoimmune thrombocytopenia (Evans syndrome)
+***[[Autoimmune thrombocytopenia]] (Evans syndrome)
-** Congenital
+**Congenital: [[common variable immune deficiency]]
+**Neoplasm: [[lymphoproliferative disorder]]
-*** Common variable immune deficiency
+**Medications
-** Neoplasm
-*** Lymphoproliferative disorders
-** Medications
-== Investigations ==
+==Investigations==
-* CBC
+*CBC
-** Mean platelet volume can suggest high platelet turnover
+**Mean platelet volume can suggest high platelet turnover
-* Peripheral blood film
+*Peripheral blood film
-* HIV and HCV testing
+*HIV and HCV testing
-* Additional
+*Additional
-** Abdo ultrasound for splenomegaly and liver disease
+**Abdo ultrasound for splenomegaly and liver disease
-** Rh status
+**Rh status
-** DAT for Evan's syndrome
+**DAT for Evan's syndrome
-** Quantitative immunoglobulins
+**Quantitative immunoglobulins
-** Hep B testing
+**Hep B testing
-** H. pylori, if at risk
+**H. pylori, if at risk
-** Antiphospholipid antibodies
+**Antiphospholipid antibodies
-** ANA, anti-dsDNA
+**ANA, anti-dsDNA
-** Thyroid tests
+**Thyroid tests
-** vWF testing (for type 2B vWD)
+**vWF testing (for type 2B vWD)
-** Bone marrow biopsy
+**Bone marrow biopsy
-== Management ==
+==Management==
+===Acute management===
-* Only needs treatment if platelets lower than 30 or if bleeding
-* First-line:
+*Only needs treatment if platelets lower than 30 or if bleeding
-** Steroids
+*'''First-line:'''
-*** Prednisone 1-2mg/kg/day x3weeks then taper (70-80% response but high relapses over next 10 years)
+**Steroids
-*** Dexamethasone 40mg/d po x4days ever 2-4 weeks, repeated for 3-6 cycles (90% response)
+***Prednisone 1-2mg/kg/day x3weeks then taper (70-80% response but high relapses over next 10 years)
-** IVIg 1-2g/kg x1-2 days, if refractory to steroids or requires rapid treatment
+***Dexamethasone 40mg/d po x4days ever 2-4 weeks, repeated for 3-6 cycles (90% response)
-** Anti-D if Rh positive and has a spleen
+**IVIg 1-2g/kg x1-2 days, if refractory to steroids or requires rapid treatment
-* Second-line:
+**Anti-D if Rh positive and has a spleen
-** Splenectomy
+*'''Second-line:'''
-*** Ensure vaccinated for Hib, Strep pneumo, and N. meningitidis
+**Splenectomy
-** Rituximab
+***Ensure vaccinated for Hib, Strep pneumo, and N. meningitidis
-** Thrombopoeitin agonists: eltrombopag or romiplostim
+**Rituximab
-** Immunosuppressive therapies: azathioprine, cyclosporin A, cyclophosphomide, danazol, dapsone, mycofenolate mofetil, vina alkaloids
+**Thrombopoeitin agonists: eltrombopag or romiplostim
-* Third-line:
+**Immunosuppressive therapies: azathioprine, cyclosporin A, cyclophosphomide, danazol, dapsone, mycofenolate mofetil, vina alkaloids
-** Almtuzumab, chemotherapy, stem cell transplant
+*'''Third-line:'''
-* For life-threatening bleed:
+**Almtuzumab, chemotherapy, stem cell transplant
-** IVIG 1g/kg, repeated once more if platelets remain below 50 the next day
+*'''For life-threatening bleed:'''
-** Pulse steroids: methylprednisolone 30mg/kg IV daily x2-3 days)
+**IVIG 1g/kg, repeated once more if platelets remain below 50 the next day
-** Tranexamic acid 1G IV q6h
+**Pulse steroids: methylprednisolone 30mg/kg IV daily x2-3 days)
-** Platelet transfusion
+**Tranexamic acid 1G IV q6h
-** Emergency splenectomy
+**Platelet transfusion
-** Last-ditch: recombinant factor VIIa 90mcg/kg IV q2h
+**Emergency splenectomy
-*** High risk for clotting
+**Last-ditch: recombinant factor VIIa 90mcg/kg IV q2h
+***High risk for clotting
 [[Category:Hematology]]