Title : A case of meningoencephalitis due to dual infection with streptococcus pneumoniae and herpes simplex Virus 1
Abstract:
Meningoencephalitis is a serious and life-threatening infection with high mortality rates worldwide. Streptococcus pneumoniae is one of the most common infectious agents causing bacterial meningoencephalitis. Herpes Simplex Virus 1 (HSV-1) causes viral meningoencephalitis in an estimated 2 to 4 persons per 1,000,000 worldwide. Very rarely, meningoencephalitis can be due to dual infections with both bacterial and viral agents. A 69-year-old woman with diabetes and migraines was seen in the Emergency Department (ED) for headaches, treated with antiemetics and opioid pain medications, then discharged home. She was then found unresponsive and admitted with acute encephalopathy.
Work-up revealed Escherichia coli urinary tract infection (UTI). On hospital day 5, she developed a new-onset generalized tonic-clonic seizure. Magnetic resonance imaging (MRI) of her brain revealed “extensive leptomeningeal enhancement overlying the frontal lobes bilaterally with a small focus in the left temporal lobe”, consistent with meningoencephalitis. Cerebrospinal fluid (CSF) was positive for S. pneumoniae with negative preliminary HSV PCR results. She responded well to vancomycin and ceftriaxone and was discharged home. 1 day after discharge, completed HSV PCR resulted positive.
Acyclovir was added to her antimicrobial regimen and she responded well. This patient’s diagnosis was delayed and complicated due to multiple factors, including polypharmacy and a concurrent UTI, however her hospital course prompted further work-up which revealed meningoencephalitis, consistent with her initial presenting complaint of headaches. Interestingly, she was found to have both bacterial and viral infections. This complex case illustrates the importance of considering all differential diagnoses, including rare ones, and conducting a full diagnostic work-up while avoiding anchoring.
Objective:
1) To illustrate the importance of a full diagnostic work-up
2) To highlight the value of avoiding anchoring on “most common” explanations and diagnoses
3) To raise awareness of initial false-negative polymerase chain reaction (PCR) results
