An important diagnosis to consider in recurrent meningitis
A 21-year-old Caucasian male was reviewed in our clinic with a history of Streptococcus pneumoniae meningitis and bacteraemia complicated by pneumonia requiring intensive care unit admission. He recovered well following treatment with intravenous ceftriaxone. Assessment of his immune system revealed an isolated borderline low IgG level (6.3 g/L, normal range 7–16 g/L), borderline low C4 level (15 mg/dL, normal range 16–54 mg/dL) and low pneumococcal antibody titres (16 mg/L, protective range >50). At the time of his first episode, his IgG level was also noted to be low (5.1 g/L, normal range 7–16 g/L). Viral testing was negative. He was vaccinated with 23-valent pneumococcal polysacharide vaccination and made an appropriate antibody response.\nHe continued to report tiredness and general malaise and just over a year later, at age 23, developed a second episode of pneumococcal meningitis. This again responded well to intravenous antibiotics. Serotype-specific pneumococcal antibodies were measured after the second episode and low titres to 7 of the 13 measured pneumococcal serotypes were found. There was no history of head trauma with either episode nor of CSF rhinorrhoea.\nThe past medical history included autoimmune hepatitis and Crohn’s disease, requiring low-dose maintenance oral steroids. Other medication intermittently used included mesalazine, mercatopurine and methotrexate. He had had recurrent tonsillitis as a child and had a tonsillectomy at the age of 20.\nInitial routine CT head was reported as normal. However, detailed sinus CT showed an anomalous, prominent right agger nasi ethmoid air cell extending up to the skull base with sclerotic thickened bony walls and opacification within (). This was diagnosed as a mucocoele of this anomalous air cell. It was surgically decompressed.\nLong-term pneumococcal antibiotic prophylaxis and pneumococcal vaccination were given as preventative measures. Currently, his IgG and complement levels are within normal range.