Approach to thrombocytopenia.pptx

Thrombocytopenia is generally defined as platelet count <150 × 109/L. It can occur due to several reasons, like decreased platelet production (e.g., inherited bone marrow failure syndromes, acquired aplastic anemia, leukemia), ineffective platelet production (myelodysplastic syndrome, megaloblastic anemia), increased destruction (ITP, HLH), increased consumption (DIC, TTP, HUS), sequestration (hypersplenism), or may be due to combination of multiple mechanisms described above.
During evaluating a case of thrombocytopenia, the first step is getting a detailed history and doing a proper clinical examination. Then the next step would be checking the other parameters of complete blood count (CBC), especially hemoglobin (Hb) and the total WBC count, complemented by a peripheral smear (PS) examination, which will clear many doubts and will help us pinpointing our diagnostic approach.
Many a times pseudo-thrombocytopenia is encountered in a PS due to platelet clumping by EDTA and can be rectified by collecting blood samples in a citrate or heparin vials or by doing a direct finger prick smear. Any accompanying cytopenia will expand the differential diagnosis and an isolated thrombocytopenia will further narrow it down. Presence of any additional abnormalities of red cells (megaloblasts) or white cells (presence of hyper-segmented neutrophils, atypical lymphoid/myeloid cells) could be present in megaloblastic anemia/MDS, leukemia respectively, while in the presence of fragmented red cells microangiopathic hemolytic anemia should always be ruled out by doing PT and aPTT (DIC, TTP, HUS). In case of isolated thrombocytopenia, the platelet morphology is also important. In many patients in India, especially in eastern region many people have large platelets with their normal platelet count around 100 × 109/L with normal platelet function (Harris platelet syndrome). However, presence of any abnormal platelet morphology along with a low platelet count may indicate a platelet function disorder (large platelets in Bernard Soulier syndrome/ Glanzmann thrombasthenia or small platelets in Wiskott-Aldrich syndrome), especially if encountered in early part of life during evaluation for bleeding symptoms. In case of isolated thrombocytopenia, presence of additional congenital anomalies may point out towards an inherited marrow failure syndrome, e.g. amegakayocytic thrombocytopenia. Exposure to certain drugs may result in isolated low platelet count, e.g., ceftriaxone, piperacillin, heparin. Presence of toxic changes in neutrophils may indicate sepsis related thrombocytopenia. By excluding all these, immune thrombocytopenia (ITP) to be thought as no specific tests or markers are available for this entity and its diagnosis is largely clinical. A further work up complemented by bone marrow examination and in few cases a platelet function test will definitely help in reaching the final diagnosis.
So, summarizing, in the evaluation of a case of thrombocytopenia, all the

1. Diagnostic approach to Thrombocytopenia Dr Pritish Chandra Patra Associate Professor Dept. of Clinical Hematology, Hemato -Oncology & Stem Cell Transplant IMS & SUM Hospital, Bhubaneswar

2. A normal platelet count A study from the USA involving over 12,000 adults in the National Health and Nutrition Examination Survey (NHANES) database found the following: Platelet count Range from: 150,000 - 450,000/ microL Slightly higher mean values in females (266,000/ microL ) than males (237,000/ microL ) Slightly higher in younger people than older people

3. What is a low platelet count? Thrombocytopenia - defined as a platelet count below the lower limit of normal: <150,000/ microL Degrees of thrombocytopenia- further subdivided into Mild (100,000 - 150,000/ microL ) Moderate (50,000 - 99,000/ microL ) Severe (<50,000/ microL ) Numbers Vs underlying disease ( eg , in ITP, platelet count <30,000/ microL - severe thrombocytopenia) Clinical significance - Severe thrombocytopenia (platelet count <30,000 - 50,000/ microL ) greater risk of bleeding- intracranial implies a greater likelihood for needing treatment

4. Thrombocytopenia: basic mechanisms

5. Thrombocytopenia- approach to diagnosis

6. 1 st step: Rule out Pseudo-thrombocytopenia Repeat platelet count by automated cell counter Check platelet histogram Peripheral blood smear Giant platelets Platelet clumps Platelet morphology Large- Bernard Soulier syndrome Glanzmann thrombasthenia Small- Wiskott -Aldrich syndrome Often reveals the etiology (e.g. Acute Leukemia) Platelet count with non- EDTA vials ( Citrate , Heparin ) Platelet count by direct finger prick smear

7. Other helpful platelet indices By automated hematology analyzers Large platelet

8. Thrombocytopenia- approach to diagnosis

9. Lab investigations

10. ITP (Immune Thrombocytopenia) Auto-immune platelet destruction Isolated thrombocytopenia ± bleeding (mild-severe) WBC total and differential count- normal for age Anemia- proportionate to blood loss No abnormal cells in PBS Primary ITP- no organomegaly/lymphadenopathy (usually)

11. BMA/Biopsy- Normal/increased number of megakaryocytes Normal morphology Work up for secondary causes HIV HCV SLE Lymphoma (e.g. CLL) ITP is a diagnosis of exclusion ITP (Immune Thrombocytopenia)

12. Case studies

13. Case-1 25yr lady Acute onset of bleeding- spontaneous skin bruising, gum bleed, menorrhagia No fever / bone pain O/E- clinically stable, mild pallor, multiple ecchymoses, & purpuric spots, liver/spleen/LN- not enlarged CBC: Plt - 10,000/ cumm , Hb, TLC, DLC- normal PBS- no abnormal cells

14. Diagnosis? ITP BMA/Biopsy- Normal Work up for secondary ITP: Negative 1 st line treatment: Prednisolone / High-dose Dexamethasone / ± IVIG 2 nd line: Rituximab / TPO-RA ( Eltrombopag /Romiplostim) 3 rd line: Azathioprine, Dapsone, MMF etc Refractory- Splenectomy

15. Case 2 65 yr old lady Acute onset spontaneous skin bruising, gum bleed No fever / bone pain O/E- clinically stable, mild pallor, multiple ecchymoses & purpuric spots, liver/spleen/LN- not enlarged CBC- Plt - 15,000/ cumm , Hb- 9 g/dL, TLC- 80,000/ cumm , DLC- N20 L75 M5, Retic- 8% PBS- small mature lymphocytes, smudge cells+ Direct Coombs Test (DCT)- Positive- 3+

16. Diagnosis? Flowcytometry- CLPD panel- s/o Chronic Lymphocytic Leukemia (CLL) BMA+Biopsy - increased lymphoid cells, megakaryocytes increased- both mature and immature forms, no dysplasia. Diagnosis- Evan’s Syndrome (AIHA+ITP), secondary to CLL 1 st line treatment Corticosteroids (Prednisolone) If no response- Rituximab ± Bendamustine

17. Case 3 5 yr old girl Acute onset of spontaneous skin bruising, epistaxis Fever on and off x 1 month, fatigue Look sick, febrile, pallor++, multiple ecchymoses & purpuric spots Multiple cervical LNs, Spleen palpable 3cm CBC: Plt - 10,000/ cumm , Hb- 6 gm/dL, TLC- 25,000/ cumm PBS- Blasts- 60%, no auer rods

18. Diagnosis? Acute leukemia PB / BM- immunophenotyping- flowcytometry- B cell ALL Cytogenetics, NGS Treatment Chemotherapy (pediatric ALL regimen) Supportive treatment (with platelet transfusions)

19. Case 4 30 yr old lady Acute onset menorrhagia, spontaneous skin bruising, epistaxis, hematuria- 7 days Decreased vision in B/L eye- 1 day Looks sick, febrile, pallor++, multiple ecchymoses & purpuric spots, B/L sub-conjunctival hemorrhage CBC: Plt - 5000/ cumm , Hb- 6 g/dl, TLC- 5000/ cumm PBS: hypergranular promyelocytes with blasts 50% PT, aPTT - prolonged Fibrinogen- 40 mg/dl D-dimer high s/o DIC

20. Diagnosis? Acute promyelocytic leukemia (APML) with DIC Urgent transfusion- RDP / SDP + FFP + Cryoprecipitates ATRA + ATO- to start urgently Send from PB- RT-PCR / FISH for PML RARA BMA + Biopsy + Cytogenetics Continue ATRA + ATO after APML is confirmed

21. Case 5 60 yr old male Spontaneous skin bruising, gum bleed, epistaxis- 1 month Fatigue- 3 months, h/o PRBC transfusion 4 units for anemia Afebrile, pallor++, multiple ecchymoses, wet purpura in oral mucosa Liver/spleen/LN- not enlarged CBC: Plt - 10,000/ cumm , Hb- 6 g/dl, TLC- 1500 (N25 L70 M5) Retic- 0.5%, Absolute reticulocyte count- 10,000 PBS- no blasts

22. Diagnosis? D/D- aplastic anemia/MDS/acute leukemia BMA+Biopsy+Cytogenetics +/- Flowcytometry BMA+Biopsy - hypocellular marrow (20% cellularity), no increase in blasts, no dysplasia Cytogenetics- 46XY Diagnosis- Aplastic anemia Trt - IST ( ATG+Cyclosporine+Eltrombopag ) Supportive treatment- PRBC+RDP transfusions D/D- aplastic anemia/MDS/acute leukemia BMA+Biopsy+Cytogenetics +/- Flowcytometry BMA+Biopsy - hypercellular marrow (70% cellularity), 3% blasts, trilineage dysplasia Cytogenetics- 46XY, +8 Diagnosis- MDS Trt - Low risk: EPO + G-CSF  hypomethylating agents High risk: Hypomethylating agents Others (isolated 5q del)- Lenalidomide Supportive treatment- PRBC+RDP transfusions

23. Case 6 50 yr old male Known CLD Referred from Gastro OPD for thrombocytopenia Afebrile, pallor+, no active bleeding Splenomegaly 3cm CBC: Plt - 30,000/ cumm , Hb- 10 g/dl, TLC- 3500 (N65 L30 M5) PBS- no atypical cells

24. Diagnosis? ? Hypersplenism- secondary to CLD + Portal HTN BMA+Biopsy : Normocellular marrow, normal trilineage maturation Cytogenetics: 46XY Trt - Supportive Iron and B12 replacement if deficient Treatment of CLD & Portal HTN

25. Summary

26. Thank You