Clinical, cerebrospinal fluid, and microbiological characteristics of childhood purulent meningitis at a tertiary pediatric hospital in Vietnam: a retrospective study

Technical Summary: Clinical, Cerebrospinal Fluid, and Microbiological Characteristics of Childhood Purulent Meningitis in Vietnam

Problem Statement
Purulent meningitis remains a life-threatening infection in children, particularly within low- and middle-income settings where delayed recognition and limited microbiological confirmation pose significant clinical challenges. While global burden estimates indicate a high incidence of bacterial meningitis in children under five, updated hospital-based data regarding the specific etiology, clinical presentation, and diagnostic profiles of pediatric purulent meningitis in Vietnam are limited. Existing literature suggests that clinical presentation is often age-dependent and non-specific in infants, and that prior antibiotic use frequently reduces culture yields, complicating early diagnosis and pathogen identification.

Methodology
This study employed a retrospective descriptive design conducted at the Vietnam National Children's Hospital, a tertiary pediatric referral center in Hanoi. The study population consisted of 102 children hospitalized between January 2021 and December 2023 with a discharge diagnosis of purulent meningitis.

• Inclusion Criteria: Children with a clinical diagnosis of purulent meningitis supported by cerebrospinal fluid (CSF) findings compatible with bacterial meningitis (pleocytosis, neutrophil predominance, elevated protein, decreased glucose, positive Pandy reaction, or pathogen identification).
• Exclusion Criteria: Children with major underlying neurological or systemic conditions that could alter clinical or CSF profiles, or those with incomplete medical records.
• Data Collection: Researchers extracted demographic data, time from symptom onset to admission, presenting clinical features, peripheral blood findings, CSF profiles, and microbiological results from medical records.
• Analysis: Data were analyzed using SPSS version 20.0, with categorical variables summarized as frequencies and percentages. The study was approved by the Institutional Review Board of the Vietnam University of Traditional Medicine, with informed consent waived due to the retrospective nature of the de-identified data.

Key Results
The analysis of the 102 pediatric cases yielded the following characteristics:

• Demographics: The disease burden was concentrated in children under 5 years of age (74.5% of cases), with a male predominance (66.7%). The most common interval from symptom onset to admission was 1–3 days (42.2%), though 27.4% of patients presented after more than 7 days.
• Clinical Presentation: Fever was the most frequent presenting feature (93.1%), followed by vomiting (45.1%), altered consciousness (40.2%), seizures (34.3%), and headache (31.4%). Notably, classic meningeal signs were uncommon: neck stiffness was present in only 28.4% of cases, and a positive Kernig sign in only 2.9%. Bulging fontanelle was documented in 7.8% of cases.
• Laboratory Findings (Peripheral Blood): Inflammatory abnormalities were common but not uniform. Neutrophil predominance was observed in 69.6% of cases, and C-reactive protein (CRP) was elevated (>6 mg/L) in 70.6%. White blood cell counts were normal in 50.0% of children.
• Laboratory Findings (CSF): CSF abnormalities were prominent. Elevated protein was found in 70.6% of cases, a positive Pandy reaction in 65.7%, and pleocytosis (cell count ≥100 cells/mm³) in 76.5%. In contrast, significantly reduced CSF glucose (<2.2 mmol/L) was observed in only 30.4% of cases.
• Microbiological Etiology: A bacterial pathogen was identified in CSF cultures in 30.4% of cases (31/102). Streptococcus pneumoniae was the leading identified pathogen, accounting for 21.6% of the total cohort. Other identified pathogens included Group B Streptococcus (4.9%), Escherichia coli (2.9%), and Haemophilus influenzae (1.0%). The majority of cases (69.6%) were culture-negative.

Key Contributions
This study provides updated, hospital-based data characterizing the clinical and microbiological landscape of childhood purulent meningitis in a Vietnamese tertiary setting. Its primary contributions include:

1. Clinical Profile Validation: Confirming that in this setting, the clinical presentation is dominated by non-specific infectious and neurological symptoms (fever, vomiting, altered consciousness, seizures) rather than classic meningeal signs, particularly in children under five.
2. Diagnostic Nuance: Demonstrating that CSF abnormalities, specifically elevated protein and pleocytosis, are more consistent diagnostic indicators than markedly reduced CSF glucose, which was absent in the majority of cases.
3. Etiological Data: Establishing Streptococcus pneumoniae as the predominant identified pathogen in this cohort, despite a low overall culture yield (30.4%), highlighting the limitations of conventional culture in routine practice.

Significance and Claims
The authors claim that these findings underscore the necessity for clinicians to maintain a high index of suspicion for purulent meningitis in children presenting with fever and neurological symptoms (such as seizures or altered consciousness), even in the absence of classic meningeal signs like neck stiffness. The study emphasizes that early CSF evaluation remains essential for diagnosis, as reliance on classic physical signs alone may lead to delayed recognition. Furthermore, the data supports the view that increased CSF protein and cellular response are more reliable diagnostic markers than severe hypoglycorrhachia in this population. The study concludes that while microbiological confirmation is often limited in routine practice, Streptococcus pneumoniae remains the leading identified cause of severe disease, reinforcing the need for early diagnostic intervention and appropriate empirical management in pediatric referral settings.