A Case of IVIG-Induced Aseptic Chemical Meningitis.

Intravenous immunoglobulin (IVIG) is a commonly used and generally well-tolerated medication. Common side effects include flu-like symptoms such as fevers, headaches, myalgia, fatigue, and nausea. One of the more rare side effects is aseptic meningitis, with a reported incidence rate of around 0.067 percent of all IVIG infusions. In this paper, we describe a 47-year-old female patient with a history of myasthenia gravis who presented with a headache, neck pain, and neck stiffness while undergoing IVIG infusions for a myasthenia crisis. On admission day, the patient was afebrile with stable vital signs. A physical examination revealed nuchal rigidity and tenderness with no focal neurological deficits. Cerebrospinal fluid (CSF) cytology noted an elevated white blood cell (WBC) count of 1,138 cells/μL with a neutrophil predominance (96 percent). CSF red blood cell count was unremarkable at 1 cell/μL. The patient's IVIG infusions were stopped, suspecting chemical meningitis. Given the markedly elevated CSF WBC count with neutrophil predominance, she was started on vancomycin and ceftriaxone to also cover for bacterial meningitis. The patient's meningeal signs and symptoms significantly improved 24 hours after admission. Given the clear temporal relationship to IVIG administration and the rapid improvement of symptoms, IVIG-induced aseptic meningitis is strongly suspected. The patient's antibiotics were discontinued. Forty-eight hours after stopping IVIG and 24 hours after discontinuing antibiotics, her meningitis symptoms completely resolved with the use of analgesics alone. The patient was then discharged uneventfully. CSF viral and bacterial studies, including a gram stain and cultures, did not result in anything noteworthy. Our case presents an interesting diagnostic dilemma where drug-induced (IVIG) aseptic meningitis mimics bacterial meningitis clinically and on CSF analysis. The clear temporal relationship to IVIG administration and the rapid resolution of symptoms upon stopping the drug can aid in the diagnosis of this rare event and help doctors avoid the use of unnecessary antibiotic therapy.