Invasive meningococcal disease without meningitis: a forgotten diagnosis

Neisseria meningitidis, a Gram-negative diplococcus, is an uncommon cause of pneumonia. There have been only about 344 cases reported worldwide from 1906 to 2015. To our knowledge, there have been only 3 cases reported in the USA in the past 2 decades. We present a case of a 72-year-old male with a past medical history of severe COPD, obstructive sleep apnea, and stage I lung cancer status post-stereotactic body radiation therapy 1 year ago, who was admitted with a 6-day history of productive cough with yellowish sputum, shortness of breath, extreme myalgias, and fatigue. Chest X-ray revealed an infiltrative process in the left lower lung field and left-sided pleural effusion. Blood cultures grew beta-lactamase-negative N. meningitidis after 24 hours. Our patient was initially treated with broad-spectrum antibiotics, which were later switched to amoxicillin to complete a total of 14 days of antibiotics. Diagnosing meningococcal pneumonia requires a high level of suspicion, as sputum cultures may be falsely positive due to asymptomatic carriage of the organism in the upper respiratory tract in up to 10% of outpatient population. We highlight this case as early recognition and treatment is critical. The case fatality rate for N. meningitidis pneumonia has been reported to be higher compared with meningococcal meningitis.