Clinical and laboratory characteristics and factors associated with mortality in meningococcal infection at Military Hospital 175, Vietnam: a retrospective case series

Technical Summary: Clinical and Laboratory Characteristics and Factors Associated with Mortality in Meningococcal Infection at Military Hospital 175, Vietnam

Problem Statement
Meningococcal infection, caused by Neisseria meningitidis, is a rapidly progressive disease with high mortality, often presenting as meningitis and/or septicemia. While global literature identifies prognostic factors such as impaired consciousness and shock, data specific to Vietnam remains scarce. The disease in Vietnam typically occurs sporadically rather than in large outbreaks, limiting comprehensive clinical studies. Furthermore, military populations represent a distinct high-risk group due to close-contact living conditions that facilitate transmission. This study addresses the gap in local data by characterizing the clinical and laboratory profile of meningococcal infection in a Vietnamese military setting and identifying factors associated with in-hospital mortality.

Methodology
The study was a retrospective case series conducted at Military Hospital 175 in Ho Chi Minh City, Vietnam, covering the period from January 2016 to December 2025.

• Population: The study included 17 patients with microbiologically confirmed Neisseria meningitidis (via culture and/or PCR) who had sufficient clinical and laboratory data.
• Grouping: Patients were stratified into two groups: survivors (n=14) and non-survivors (n=3).
• Data Collection: Clinical features, laboratory findings (hematological, biochemical, coagulation), cerebrospinal fluid (CSF) parameters, and treatment outcomes were extracted from medical records.
• Statistical Analysis: Continuous variables were reported as median (interquartile range, IQR) and compared using the Mann–Whitney U test. Categorical variables were compared using Fisher's exact test. A two-sided p-value < 0.05 was considered statistically significant. The authors acknowledged the risk of Type I error due to the small sample size and multiple comparisons. Variables with substantial missing data (e.g., D-dimer) were excluded from comparative analysis.

Key Results
The overall in-hospital mortality rate was 17.6% (3/17). Significant differences were observed between survivors and non-survivors across clinical, laboratory, and CSF domains:

• Clinical Presentation: Non-survivors presented with significantly more severe neurological impairment and systemic collapse.

  • Glasgow Coma Scale (GCS): Non-survivors had a median GCS of 5 (IQR 3–7) compared to 10 (IQR 10–14) for survivors (p=0.04). All non-survivors had severe impairment (GCS < 8), versus 21.4% of survivors (p=0.01).
  • Shock and Respiratory Failure: 100% of non-survivors presented with shock and required mechanical ventilation, compared to 21.4% and 28.6% of survivors, respectively (p=0.02 and p=0.03).
  • Other symptoms like vomiting, neck stiffness, and petechiae did not differ significantly between groups.

• Laboratory Findings (Blood): Non-survivors exhibited markers of severe systemic illness, including:

  • Thrombocytopenia: Significantly lower platelet counts (60 G/L vs. 155 G/L; p=0.028).
  • Metabolic Derangement: Markedly elevated lactate (23 mmol/L vs. 4.1 mmol/L; p=0.01) and severe metabolic acidosis (pH 7.11 vs. 7.36; p=0.02).
  • Coagulopathy: Reduced prothrombin levels (22% vs. 56%; p=0.03).
  • Organ Dysfunction: Elevated creatinine (236.7 µmol/L vs. 83 µmol/L; p=0.041) and urea levels, indicating renal impairment. AST levels were also significantly higher in non-survivors (p=0.047).

• Cerebrospinal Fluid (CSF): Among 14 patients with CSF data, the CSF-to-blood glucose ratio was significantly lower in non-survivors (0.11 vs. 0.32; p=0.03). Other CSF parameters, including protein, absolute glucose, lactate, and white blood cell counts, did not show statistically significant differences, though CSF lactate showed a trend toward elevation in non-survivors.

• Outcomes: Non-survivors had a significantly shorter hospital stay (median 1 day vs. 20 days for survivors; p=0.001), reflecting early mortality. The use of CRRT and therapeutic plasma exchange did not differ significantly between groups.

Key Contributions and Significance
The paper contributes to the limited body of literature on meningococcal infection in Vietnam by providing a detailed clinical and laboratory profile of a military cohort. The study identifies a distinct pattern of mortality associated with:

1. Severe Systemic Disease: Mortality is strongly linked to markers of fulminant sepsis, including circulatory collapse (shock), profound metabolic acidosis, and multi-organ dysfunction (renal and hepatic).
2. Neurological Status: Impaired consciousness (low GCS) serves as a critical early predictor of poor outcomes.
3. Prognostic Utility of CSF Glucose Ratio: The study suggests that the CSF-to-blood glucose ratio may offer additional prognostic value beyond standard CSF indices, distinguishing fatal cases from survivors.

Authors' Claims and Limitations
The authors conclude that early recognition of impaired consciousness, shock, metabolic derangement, coagulopathy, and organ dysfunction is essential for guiding timely intensive management. They posit that the CSF-to-blood glucose ratio may provide supplementary prognostic information.

The paper maintains a modest tone regarding its claims, explicitly noting several limitations:

• Sample Size: The small cohort (n=17) and the very small number of non-survivors (n=3) reduce statistical power.
• Generalizability: As a single-center study focused on a military population, the findings may not be directly generalizable to broader civilian settings in Vietnam.
• Data Completeness: Missing data for certain variables (e.g., D-dimer, urea in non-survivors) limited the scope of comparative analysis, requiring cautious interpretation of those specific results.
• Statistical Risk: The authors acknowledge the potential for Type I error due to multiple comparisons in a small sample.

The study does not propose new treatments or future experimental protocols but emphasizes the need for early identification of high-risk features to improve clinical management in this specific population.