Usefulness of platelet indices in differentiating thrombocytopenia with and without bone marrow

megakaryocytosis.

Introduction• In evaluating the mechanism of thrombocytopenia, it is

necessary to know which is more dominant, hypo-productive thrombocytopenia or hyper-destructive thrombocytopenia.

• For this purpose, bone marrow aspiration, platelet-associated immunoglobulin G (PAIgG), and molecular markers for disseminated intravascular coagulation (DIC) are often evaluated.

• Bone marrow aspiration provides information about platelet production, such as the number of megakaryocytes and the degree of platelet production, while PAIgG identifies the presence of anti-platelet antibodies that lead to platelet destruction.

• Bone marrow examination, which is an invasive test, is necessary for aplastic anaemia (AA), but there is no agreed consensus regarding its necessity for immune thrombocytopenia (ITP)

• PAIgG is often elevated in ITP, but it is not specific to ITP and an increased PAIgG level is often found in many other diseases.

• In fact, the necessity for both bone marrow aspiration and PAIgG in ITP was not accepted in the recent guidelines (British Committee for Standards in Haematology General Haematology Task Force, 2003).

• However, these two diagnostic approaches are actually overused in the diagnosis of ITP.

• Recent advances in automated blood cell analysers have made it possible to measure various blood cell parameters automatically.

• Among these parameters, platelet indices, such as mean platelet volume (MPV), platelet size deviation width (PDW), and platelet large cell ratio (P-LCR), provide some important information but are not accepted for routine clinical use.

• If these indices really are informative regarding platelet kinetics, they might become very useful laboratory measures for thrombocytopenia.

• This study will investigate the significance of these platelet indices in the diagnosis of thrombocytopenia associated with increased bone marrow megakaryopoiesis by comparing the levels in hypo- or normoproductive conditions and in hyper-productive thrombocytopenia.

• As Immune thrombocytopenia is the commonest cause of hyper-destructive thrombocytopenia and also the commonest cause of thrombocytopenia in clinical settings, any usefulness of platelet indices in investigating thrombocytopenia with bone marrow megakaryocytosis can be attributed to ITP as well.

• The sensitivity and specificity of platelet indices to enable the diagnosis of hyper-destructive thrombocytopenia will be evaluated in this study.

Objectives

• General Objective:– To assess the usefulness of platelet indices in the

investigation of thrombocytopenia

Specific objectives: To study the pattern of platelet indices in cases with

increased, normal and decreased megakaryocytes in the bone marrow.

To find out any variation in platelet indices relative to age, sex or any other clinical attribute.

Literature Review-1 Platelet size deviation width, platelet large cell ratio, and meanplatelet volume have sufficient sensitivity and specificity in the

diagnosis of immune thrombocytopenia

Author and Publication Study Objective and Design

Conclusion

Ken Kaito,1 Hiroko Otsubo, 2Noriko Usui, 2 Miyuki Yoshida, 1 Jyunko Tanno,1Etsuko Kurihara, 1 Kozue Matsumoto,1 Ryuzo Hirata, 1Kenichi Domitsu 1 andMasayuki Kobayashi 2

1Central Clinical Laboratory, Jikei University Hospital, and 2Division of Hematology andOncology, Department of Internal Medicine, JikeiUniversity, School of Medicine, Tokyo, JapanBritish Journal of Haematology , 128, Feb2005

Objective : to study the significance of MPV, PDW and P-LCR in the diagnosis of thrombocytopenia by comparing the levels in hypo-productive (AA) and hyper-destructive thrombocytopenia (ITP).

Design:Prospective study

•These indices could help to distinguish hyper-destructive thrombocytopenia and hypo-productive thrombocytopenia very easily. •Platelet indices, if reported, provide a lot of clinical information about the underlying conditions of thrombocytopenia. •More attention should be paid to these indices for the diagnosis of thrombocytopenia.

Literature Review-2Immature Platelet Count: A Simple Parameter for Distinguishing Thrombocytopenia

in Pediatric Acute Lymphocytic Leukemia From Immune Thrombocytopenia

Author and Publication Study Objective and Design

Conclusion

Gabriele Strauß, MD , 1Cora Volle rt, 1 Ar end von Stacke lberg , MD ,2 Andr eas Weimann, MD , 3Ger hard Gaedick e, MD , 1and Harald Schu lze, PhD1*Berlin

Pediatric Blood Cancer 2011;57:641–647

Objective : to study whether immature platelet count can be of use in distinguishing thrombocytopenia in pediatric ALL from ITP

Design:Prospective study

•IPF% is a useful parameter for defining thrombocytopenia resulting from defective platelet production while the absolute IPF number (IPF#) has the potential to distinguish acute ITP from thrombocytopenia due to diagnosed ALL in children.

Literature Review-3The Automated Complete Blood Cell Count: Use of the Red Blood Cell Volume Distribution Width and

Mean Platelet Volume in Evaluating Anemia and Thrombocytopenia

Author and Publication Study Objective and Design

Conclusion

Anand Karnad, MD; Thomas R. Poskitt, MD

Hematology-Oncology Section, Veterans Administration Medical Center (Dr Poskitt), and the Departments of Internal Medicine (Drs Poskitt and Karnad) and Pathology (Dr Poskitt), Quillen-Dishner College of Medicine, East Tennessee State University, Johnson City.

Arch Intern Med. July 1985;145(7)

.

Inclusion Criteria Exclusion criteria

All cases of thrombocytopenia that undergo bone marrow aspiration study

Cases where platelet indices are not available.

Methodology• Study design: Prospective study.

– Correlation between the bone marrow megakaryocyte count and the three platelet indices.

• Setting: Pathology department, Hemato-pathology section.

• Duration: one year.

• Approval by the INSTITUTIONAL REVIEW BOARD & THE ETHICAL COMMITTEE ON RESEARCH,TUTH,IOM.

• Sample Size: All cases undergoing BM aspiration for thrombocytopenia during one year period.

Diagnosis of ITP• First, the clinician has to determine that there

are no blood abnormalities other than low platelet count, and no physical signs except for signs of bleeding. Then, the secondary causes (usually 5–10 percent of suspected ITP cases) should be excluded. Secondary causes could be leukemia, medications (e.g., quinine, heparin), lupus erythematosus, cirrhosis, HIV,hepatitis C, congenital causes, antiphospholipid syndrome, von Willebrand factor deficiency, onyalai and others.[9][2]

Investigations for Aplastic Anemia1. FBC and reticulocyte count

 2. Blood film examination

 3. HbF% in children

 4. Bone marrow aspirate and trephine biopsy, including cytogenetics

 5. Peripheral blood cytogenetics to exclude Fanconi's anaemia if <35 years old

 6. Ham test and/or flow cytometry for PIG-anchored proteins

 7. Urine haemosiderin if Ham test positive or PIG-anchored protein deficiency

 8. Vitamin B12 and folate

 9. Liver function tests

10. Viral studies: hepatitis A, B, C; EBV; CMV

11. Anti-nuclear antibody and anti-dsDNA

12. Chest X-ray

13. Abdominal ultrasound scan