Thrombocytopenia may result from many mechanisms such as marrow hypoplasia, increased destruction of platelets, and splenic sequestration. The gold standard method for discriminating the causes of thrombocytopenia is bone marrow examination, but it is invasive and expensive. Therefore, it is not recommended as a first-line diagnostic procedure. Of late, the automated blood cell analyzer has made it possible to assess the cause of thrombocytopenia through platelet indices, which include the mean platelet volume (MPV) and platelet distribution width (PDW), which are provided as a part of routine complete blood count.[1] These parameters form a preliminary, non-invasive mode of evaluating the cause for thrombocytopenia.s

Studies have shown that MPV and PDW, have a good diagnostic correlation which can be compared to findings from the study of the bone marrow. The present study attempts to find the usefulness of these platelet indices (MPV and PDW) in discriminating between hyper-destructive or hypo-productive causes of thrombocytopenia and thereby help in avoiding or delaying a request for bone marrow examination.[2]

Aim

To evaluate the diagnostic value of platelet indices in thrombocytopenic febrile illnesses.

Objective

To assess the prognostic significance of platelet indices in predicting disease severity and outcomes. To determine the potential of platelet indices in guiding treatment strategies.

A Cross sectional observational Study, conducted from January 2023 to December 2023 (12 months) at NRI Institute of Medical Sciences (NRIIMS), Visakhapatnam, Andhra Pradesh. Males and females of age group 03-88 year with thrombocytopenia and acute febrile illness considering inclusion and exclusion criteria were included in the study. Total sample size of the study is 500.Out of the 500 samples, according to the sample size calculation, 85 samples were randomly selected for analysis and interpretation of platelet indices for 3 consecutive days i.e day 1, day 2 and day3.

Sample size is according to the formula: 4pq/d² = 85. (Where = Percentage of thrombocytopenia in men = 54(Shah) [3] q = 100-p d = 20% of p). Convenience sampling technique is used. Institutional Ethical committee approved the present study.

Inclusion Criteria:

Adults both male and female of age group 03-88 years with thrombocytopenia i.e patients with platelet count<1.5lakh/mm3(with or without clinical bleeding).Participants who are willing to participate after consent.

Exclusion criteria:

Participants who received recent blood or platelet transfusions. Participants on heparin treatment and other related drugs. Participants having malignancy with thrombocytopenia and those who are not willing to participate.

Methodolgy

 Five ml of the blood was collected from the superficial vein in the anticubital fossa from the study population under sterile condition. Full blood count profile and platelet parameters like MPV, PDW, P-LCR and PCT were studied using automated cell counter (Mindray –BC780  - Direct current detection principle) and analyzer report Peripheral smears of the patient with thrombocytopenia were studied using leishmann stain to rule out psuedothrombocytopenia.( Fig1) Statistical tests done for data analysis is done using ANOVA test.

The present study included 500 samples of low platelet count with acute febrile illness received in hematology laboratory of NRI Institute of Medical Sciences, Sanghivalasa, Visakhapatnam distric

In the present study, the ages of the patients who had manifestation of thrombocytopenia with acute febrile illness were analyzed from age group 03 - 88 years and highest incidence of thrombocytopenia was noted in the age group of 41- 50 years (24 %)

In the present study out of 500 cases of thrombocytopenia 331 (66.2%) were males and 169 (33.8%) were females. In the present study out of 500 cases of thrombocytopenia with acute febrile illness 395(79%) cases were of Viral Fever, including dengue, 60(12%) cases were of malaria, 14(2.8%) cases were of sepsis, 11(2.2%) cases were of leptospirosis and other infections were 20 (4%) cases.  In the present study out of 500 cases of thrombocytopenia with acute febrile illness, 147 cases were classified into mild cases (29.4%), 233 were moderate cases (46.6%) and 120(24%) were severe cases.

Platelet indices were analysed in various etiological groups and the mean values were tabulated for analysis. (Table-1)

TABLE 1: PLATELET INDICES UNDER VARIOUS CLINICAL CONDITIONS (N=500)

 As per the criteria, Platelet indices with PDW (fl) > 18 are grouped under hyperdestructive mechanism of thrombocytopenia and low PDW (fl) < 18 for hypoproductive mechanism. In the present study 34% of participants show increased PDW values and hence grouped under hyperdestructive mechanism of thrombocytopenia.

Platelet indices were analysed for various cases and grouped as low, normal and high as per standard reference values for different etiological groups. Most of the cases have values within the normal range for all three indices irrespective of etiology.

 (Table-2)

 TABLE 2: INCIDENCE OF DISEASES ACCORDING TO INDIVIDUAL PLATELET INDICES (N=500)

Out of 500 cases, 5 patients with platelet count <20,000/microL manifested with hemorrhagic symptoms like petechiae, rash and gum bleeding and received platelet transfusions. In all these 5 cases platelet indices are analysed from the automated cell analyser suggesting elevated PDW and MPV values.

TABLE3 -COMPARISON OF PDW VALUES FROM DAY1, DAY2 AND DAY3 BY REPEATED MEASURE 0F ANOVA   (N=85)

In the present study using ANOVA test, p value is <0.05 which is statistically significant, there by PDW can be used as a reliable parameter in evaluating the mechanism of thrombocytopenia. (Table3)                        

TABLE 4: COMPARISON OF MPV ON DAY 1, DAY 2 AND DAY 3 BY REPEATED MEASURE OF ANOVA (N=85)

In the present study using ANOVA test, p value is <0.05 which is statistically significant, there by MPV can be used as a reliable parameter in evaluating the mechanism of thrombocytopenia. (Table4)

TABLE 5: COMPARISON OF PCT (%) ON DAY1, DAY2 & DAY3 BY REPEATED MEASURE OF ANOVA (N=85)

In the present study using ANOVA test, p value is <0.05 which is statistically significant, there by PCT can be used as a reliable parameter in evaluating the mechanism of thrombocytopenia. (Table5)

TABLE 6: COMPARISON OF P-LCR (%) ON DAY1, DAY2&DAY3 BY REPEATED MEASURE OF ANOVA (N=85)

In the present study using ANOVA test, p value is >0.05 which is not statistically significant, there by P-LCR cannot be used as a reliable parameter in evaluating the mechanism of thrombocytopenia. (Table6)

TABLE 7: COMPARISON OF GRADES OF THROMBOCYTOPENIA WITH SHRUTHI K BHALARA ^[6] ET AL STUDY

Relationship between demographic age, gender with MPV and PDW: Carlo L. Balduini et al. [3] suggested that the prevalence of the thrombocytopenia was higher among those at the aged between 18 and 65 years. This observation is similar to the present study. In a study done by Suresh et al. [4] showed male preponderance with males accounting to 54% and females accounting to 46% which had resemblance to the present study population. In study by Chelucci C et al. [5] it was observed that there is enhanced destruction of platelet because of platelet-virus interaction. This observation was similar to the present study, with increased PDW and MPV parameters in viral fevers. In the present study majority of the cases shows moderate degree of thrombocytopenia (47%). While in Shruthi K Bhalara et al study (%) [6] Majority of the cases shown severe degree of thrombocytopenia (50%)  (Table7)     

Comparison of MPV values from day 1 to day 3: Kaito et al. [7] stated that MPV and PDW was a useful indicator to detect thrombocytopenia, these indices have high sensitivity and specificity. Present study showed similar findings which was statistically significant.

Comparison of PDW of day 1 to day 3: Fan et al.[8] studied PDW on day 1, day 2 and day 3. They found that PDW on first day of hospitalization is a valuable parameter for evaluating the severity of hemorrhagic fever. The present study correlated with Fan et al.study. Nelson et al[9] in their study mentioned that, patients with thrombocytopenia due to destruction of platelets have larger platelets (increased MPV values), whether the loss is due to infection, hemorrhage, or immune destruction and when thrombocytopenia was due to lack of production, the platelet volume was similar to that seen in patients with normal blood cell counts. Khairkar et al. [10] completed an examination on platelet counts for deciding the exact cause for TCP. The article summarised that PDW had a correlation in separating between hyper-destructive and hypo-productive TCP. The current study is in correlation the above study. Chaudhary et al.[11] examined about the primary causes of TCP in his survey article. The review makes an induction that the significant purpose behind thrombocytopenia is because the bone marrow fails to deliver adequate number of platelets. In the present study, thrombocytopenia can be graded as accelerated destruction, impaired production and abnormal pooling based on these platelet indices. Gandhi and Akholkar[12] investigated the infections like malaria, dengue, typhoid and septicemia are the common reasons for fever with TCP and were watched for bleeding signs among which,  the dengue was the commonest reason for fever with TCP. The present study stated the similar findings with viral etiology as the commonest reason for TCP. In the present, study, viral fever including dengue was the most common etiological group followed by malaria. Hemorrhagic manifestations are seen in five patients. Regular bleeding signs were petechie/purpura and gum bleeding. 

Mean Platelet Volume and Platelet Distribution Width stands as a better parameter, obtained as a part of routine complete blood picture are statistically significant and can be used to segregate the hyper-destructive and hypo-productive causes of thrombocytopenia. In the majority of patients, it may help in delaying or avoiding unnecessary, invasive bone marrow examination.

In cases of thrombocytopenia, the clinicians need to look into platelet indices which are similar to RBC indices, which can help in arriving at probable pathophysiology of thrombocytopenia. Early suspicion, screening, diagnosis and prompt management of thrombocytopenia will effectively lower morbidity and enhance favorable prognosis.

LIMITATIONS OF THE STUDY

It may not represent the general population. The present study involved limited sample size in different age group population. Small number of cases and the short duration of study are the limitations of the present study.

ACKNOWLEDGMENTS:

The study is conducted with the support of the management of NRI Institute of Medical Sciences NRIIMS , CEO Dr S. Chandrasekhar Reddy and Dean Dr P.V.Sudhakar.

Funding: None

Conflict of interest: None declared

ETHICAL APPROVAL

The study was approved by the Institutional Ethics   Committee, RI Institute of medical sciences, Visakhapatnam Dr Bhagyalakshmi Atla, Prof & HOD provided the resources, analysis and guided in writing the original research article. Dr Sushma Sathya Malladi collected, interpretated, analysed and concluded the research article findings. Dr Subramanya Sharma and Dr Sarayu guided the statistical analysis and interpretation of the data. Dr Sandya Rani and Dr Sindhu assisted in data collection and management.

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