Background:
Neisseria meningitidis is classically associated with meningitis and septicemia. Pulmonary involvement is rare, and lung abscess formation due to this organism is exceedingly uncommon.
Case Presentation:
A 42-year-old previously healthy male presented with a 10-day history of fever, productive cough, pleuritic chest pain, and progressive dyspnea. Examination revealed febrile status and decreased breath sounds over the right lower lung zone. Laboratory investigations showed leukocytosis and elevated inflammatory markers.
Chest radiograph demonstrated a cavitary lesion in the right lower zone with an air–fluid level. Contrast-enhanced computed tomography (CT) of the thorax revealed a thick-walled, irregular cavitary lesion measuring approximately 5.2 × 4.8 cm in the posterior segment of the right lower lobe. The cavity showed a well-defined enhancing wall with an internal air–fluid level and surrounding consolidation. Adjacent ground-glass opacities and perilesional inflammatory changes were noted. No evidence of bronchial obstruction, foreign body, or underlying malignancy was identified. Mild reactive mediastinal lymphadenopathy was present without pleural effusion. These findings were consistent with a lung abscess of infectious etiology.
Microbiological evaluation revealed negative blood cultures; however, sputum culture and bronchoalveolar lavage confirmed Neisseria meningitidis. There was no evidence of meningitis or systemic meningococcemia.
Management and Outcome:
The patient was treated with intravenous ceftriaxone followed by oral antibiotics, resulting in significant clinical improvement. Follow-up CT imaging at 3 weeks demonstrated reduction in cavity size with resolution of surrounding consolidation.
Discussion:
Pulmonary manifestations of meningococcal infection are rare and may occur via aspiration or hematogenous spread. CT imaging is crucial for accurate characterization of cavitary lesions, exclusion of differential diagnoses such as malignancy or tuberculosis, and monitoring treatment response.
Conclusion:
This case highlights a rare presentation of Neisseria meningitidis infection as a pulmonary abscess. CT imaging plays a pivotal role in diagnosis and management. Early microbiological confirmation and targeted antimicrobial therapy are essential for favorable outcomes.