Factors distinguishing leukemoid reaction from hematological malignancy in children
Heeyung Kim1, Tatsuki Ikuse2, Toshihiro Matsui2
1Center for Postgraduate Education and Training, National Center for Child Health and Development, Tokyo, Japan.
Insights
Leukemoid reaction (LR) in children is often caused by infections, and distinguishing it from hematological malignancy (HM) is crucial. Factors like age, underlying conditions, and specific lab results can help differentiate these conditions.
Area of Science:
- Pediatric Hematology
- Oncology
- Clinical Pathology
Background:
- Limited information exists on the causes and outcomes of leukemoid reaction (LR) in children.
- Distinguishing LR from hematological malignancy (HM) in pediatric patients is challenging.
Purpose of the Study:
- To identify factors that differentiate pediatric leukemoid reaction (LR) from hematological malignancy (HM).
- To investigate the etiology and prognosis of LR in children.
Main Methods:
- A single-center, case-control study involving pediatric patients (<18 years) with a white blood cell (WBC) count ≥ 50,000/μL.
- Logistic regression analysis was used to identify predictive factors for LR versus HM.
Main Results:
- Infections accounted for approximately 50% of LR cases, with bacteremia and respiratory infections being most common.
- Predictive factors for LR included younger age (<2 years), presence of underlying diseases, specific WBC and platelet counts, and lactate dehydrogenase (LDH) and C-reactive protein (CRP) levels.
- While 30-day mortality was higher in the LR group, the difference was not statistically significant compared to the HM group.
Conclusions:
- Infectious diseases are a primary cause of pediatric leukemoid reaction (LR).
- Prognosis for LR may be poorer than for hematological malignancy (HM).
- Clinical factors such as age, underlying conditions, and laboratory markers (WBC, platelet count, LDH, CRP) are valuable for differentiating LR from HM.
Background:
Information on the etiology and prognosis for leukemoid reaction (LR) in children is still limited and little is known about the factors that distinguish LR from hematological malignancy (HM).
Methods:
This was a single-center, case-control study. Pediatric patients (<18 years) with a white blood cell (WBC) count of 50,000/μL or more were included in the study. Clinical information and laboratory test results were extracted from the electronic medical records. Patients were divided into the LR and HM groups. Logistic regression analysis was performed to investigate the factors that discriminated LR from HM.
Results:
We found 214 cases (115 cases in the LR group and 99 cases in the HM group) eligible for analysis. Approximately half of the LR cases were due to infectious diseases (n = 58, 50%); bacteremia and respiratory infections were the most common infections. Age younger than 2 years (odds ratio [95% confidence interval]) (2.154 [0.690-6.727]), presence of known underlying diseases (10.006 [3.119-32.102]), WBC count <60,555/μL (20.676 [6.357-67.251]), platelet count 118,000/μL or higher (15.059 [3.876-58.504]), lactate dehydrogenase (LDH) below 781 U/L (4.219 [1.378-12.915]), and C-reactive protein (CRP) ≥0.91 mg/dL (10.568 [2.736-40.825]) were identified as the predictive factors for LR by logistic regression analysis. Thirty-day mortality was higher in the LR group than in the HM group but the difference was not statistically significant (13% vs. 6%, p = 0.087).
Conclusions:
Approximately half of the etiology of LR was infectious diseases and prognosis was poorer for LR than for HM. Age, presence of known underlying conditions, and laboratory tests, including WBC count, platelet count, LDH, and CRP, may be useful in distinguishing LR from HM.
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