Case Presentation: A 62-year-old woman with a known seizure disorder was found seizing at home. She was started on anticonvulsants, given broad-spectrum antibiotics, and required intubation. Her past medical history included asthma, hypothyroidism and a resected right frontal meningioma. She was febrile, tachypnic, tachycardic and hypotensive. No other localizing source of infection was able to be determined on physical exam. She had a leukocytosis but otherwise, her initial laboratory evaluation did not reveal the source of her symptoms either. There was no growth on blood cultures or bronchial alveolar lavage. Head CT suggested ventriculitis and lumbar puncture revealed a leukocytosis without the presence of bacteria on culture. She was treated empirically for bacterial and viral meningitis. The patient improved objectively and was extubated. Repeated lumbar punctures showed decreasing cerebral spinal fluid leukocytosis, but continued to reveal no evidence of causal organisms. Repeated cytology ruled out cerebral spinal fluid lymphoma. The patient was given the diagnosis of idiopathic bacterial meningitis and discharged home on fourteen days of intravenous antibiotics. The patient returned five days after completion of the antibiotics with persistent and severe headaches. More detailed questioning revealed a long-term, intermittent history of clear drainage from her nares. Sinus and orbital imaging revealed a right-sided sinonasal encephalocele. Intrasinus endoscopy repaired the encephalocele and the patient’s symptoms improved.

Discussion: Meningitis is a life-threatening illness commonly encountered by the Hospitalist with various etiologies and presentations. Meningitis is most commonly caused by bacteria and viruses and unfortunately it still carries a relatively high morbidity and mortality despite advances in treatment and supportive care. Less common causes of meningitis include benign lymphocytic meningitis, mumps, syphilis, tic-borne illnesses, fungal infections, tuberculosis, neoplasm or drugs. Recurrent bacterial meningitis, as was suspected in our patient, can be broken down to either congenital or acquired, and then divided into anatomic, immunodeficiency, or chronic parameningeal infections. As seen in this case, anatomic variability, such as an intrasinus encephalocele, can be an uncommon cause of meningitis. Secondary encephaloceles can result from cranial trauma, operations or elevated intracranial pressure. A history of nasal polyps, recurrent meningitis, or clear rhinorrhea suggesting a CSF leak could hint towards presence of an anatomical abnormality, such as an encephalocele, that should prompt a more thorough evaluation with more detailed cross sectional imaging.

Conclusions:

The Hospitalist often has to evaluate and treat meningitis. The astute Hospitalist also must understand when to evaluate further for causes of meningitis that may allow it to come back. Recurrent bacterial meningitis or meningitis that is failing to improve with appropriate therapy should prompt a more thorough evaluation for anatomical abnormalities, immunodeficiency, or parameningeal infections.