10 Eosinophilic Meningitis: An Unrecognized Entity!

Abstract

IntroductionEosinophilic meningitis (EM) is a syndrome characterized by the presence of greater than 10 percent eosinophils in the cerebrospinal fluid. It is rare in the U.S. with outbreaks only in travelers returning from endemic areas and therefore remains a less recognized entity. However, this case demonstrates the importance of being aware of potential etiologies of EM.Case ReportThis is a 4 year old black male with a history of sickle cell disease presenting with headaches. This was treated as a pain crisis, but worsened with development of focal neurologic deficits. An evaluation included a MRI/MRA, showing cerebellar edema, and a lumbar puncture revealing 55 percent eosinophils. Serologies for Toxocara canis, Toxoplasma, lymphocytic choriomeningitic virus, and Mycoplasma were negative. There was no history of travel, exposure to undercooked snails/mollusks or neurosurgical procedures. However, there was an exposure to rat and raccoon feces; therefore, serologies for Angiostrongylus cantonensis and Baylisascaris procyonis were sent and positive for the latter. Treatment with steroids and albendazole resulted in improvement of the patient's symptoms and cerebrospinal fluid findings.DiscussionThe most common cause of EM in the pediatric population is ventriculoperitoneal shunts. Furthermore, parasitic etiologies should also be considered. First, Angiostrongylus cantonensis is a rat lung worm endemic to Southeast Asia and the Pacific Basin. Its larvae infect intermediate hosts like snails and mollusks through fecal contamination. Second, Baylisascaris procyonis is an ascarid parasite which is widely prevalent in raccoons and infects humans directly. After feco-oral contamination by humans, the larvae invade the meninges and die, eliciting a eosinophilic response. Furthermore, given the increasing peridomestication of raccoons, Baylisascaris procyonis poses a real threat to humans with potentially devastating sequelae. Clinical features include fever, headaches, visual disturbances, and neurologic deficits.ConclusionEM is a syndrome with multiple etiologies, including parasitic infections. Although rare, the worldwide prevelance of these organisms should have clinicians maintaining a high index of suspicion.