# Molecular Diagnosis in Culture-Negative Meningococcal Arthritis: A Case Report and Case-Based Literature Review

## TL;DR

This paper reports a case of meningococcal arthritis diagnosed using molecular methods when traditional cultures failed, emphasizing the importance of PCR in such diagnoses.

## Contribution

The paper contributes a case report and literature review showing the effectiveness of molecular techniques over traditional culture methods in diagnosing meningococcal arthritis.

## Key findings

- Molecular methods like PCR can confirm meningococcal arthritis when cultures are negative.
- Meningococcal arthritis may be underdiagnosed due to reliance on traditional culture methods.
- PCR-based diagnosis is more sensitive and can detect pathogens even after antibiotic use.

## Abstract

Meningococcal arthritis is a rare manifestation of invasive meningococcal disease, accounting for 1–12.5% of cases. Accurate diagnosis relies on synovial fluid analysis, blood cultures, and molecular techniques.

A 64-year-old male with a history of renal and rectal cancer presented with fever, lower limb oedema, and headache. Laboratory findings showed elevated inflammatory markers. Synovial fluid analysis was performed, and while cultures were negative, FilmArray Sepsis® Panel PCR was positive for Neisseria meningitidis, confirming the diagnosis of meningococcal septic arthritis.

A review of nine culture-negative meningococcal arthritis cases diagnosed using molecular methods is presented. Molecular diagnostic techniques, particularly PCR, offer significant advantages over traditional culture methods, including higher sensitivity and the ability to detect pathogens after antibiotic administration. In England and Wales, meningococcal septic arthritis represented 2% of all invasive meningococcal disease cases from 2010–2020. This case highlights the importance of molecular diagnostic techniques in accurately diagnosing meningococcal arthritis, especially when traditional culture methods fail. PCR-based methods are becoming essential tools in the management of this condition, potentially revealing a higher incidence than previously recognised.