A Girl’s Signs and Symptoms Suggesting Meningitis: What’s the Best Course of Action?
A previously healthy 11-year-old girl presented to the emergency department (ED) with a 3-day history of headaches, intermittent fever, nausea, vomiting, and photophobia. Two days before the current presentation, she had experienced a worsening of her headaches despite the use of ibuprofen; she had presented to the ED where she was told she had “strep throat.” She had been treated with amoxicillin and oxycodone. Because of the persistent headaches and new-onset altered mental status, she returned to the ED for reevaluation.
Physical examination findings were unremarkable. Her temperature was 37°C, blood pressure was 100/60 mm Hg, pulse rate was 84 beats/min, and respiratory rate was 18 breaths/min. She was alert, although she became somewhat dizzy upon standing. No signs of nuchal rigidity or papilledema were observed.
Her history and her unsteadiness at presentation raised a concern for meningitis. A series of laboratory tests were performed, including a lumbar puncture; the opening pressure was 38 cm H2O, and the cerebrospinal fluid (CSF) was cloudy.
CSF analysis disclosed the following values: white blood cell count (WBC), 235/µL, with 100% mononuclear cells; red blood cell (RBC) count, 1/µL; protein, 39 mg/dL; and glucose, 53 mg/dL (serum glucose, 111 mg/dL). Gram stain results were negative for bacteria. Additional laboratory studies included a comprehensive metabolic panel, a complete blood count, a C-reactive protein test, and tests for influenza A, B, and group A streptococcus, all of which had unremarkable results. A CSF sample was sent for polymerase chain reaction (PCR) analysis to detect the presence enterovirus.
What diagnosis explains the signs, symptoms, and test results?
A. Partially treated bacterial meningitis
B. Aseptic meningitis
C. Viral encephalitis
D. Subdural empyema or brain abscess
(Answer and discussion on next page)
Answer: B, aseptic meningitis
Meningitis is characterized by fever and signs of increased intracranial pressure (eg, headache, stiff neck, nausea, vomiting, variable impairment of neurologic function). Clinical symptoms alone are unreliable in differentiating bacterial meningitis from aseptic meningitis.1-3 Typically, CSF analysis, including culture and PCR testing, are necessary to delineate the diagnosis and guide appropriate management (Table).
However, having received antibiotics prior to lumbar puncture is a potential confounding factor, since antibiotic therapy can alter CSF test results and, consequently, their diagnostic utility. In particular, antibiotic pretreatment is associated with higher CSF glucose levels, lower CSF protein levels, and lower CSF culture positivity rates.1,2,4 Therefore, more-sensitive diagnostic tests such as PCR assay are essential to distinguish partially treated bacterial meningitis from aseptic meningitis.1,4 Nevertheless, PCR test results are not always available in a timely manner.
When initial CSF test results are inconclusive, and CSF culture and PCR test results are pending, a number of approaches are possible, depending on the patient’s clinical status and the suspected diagnosis. Among them are providing supportive care, then discharging the patient home; treating the patient empirically for bacterial meningitis for 72 hours; and expediting PCR test results for enterovirus detection.
Aseptic meningitis usually is self-limiting, with complete recovery in 7 to 10 days. Only supportive care such as antipyretics, analgesics, rehydration therapy, and rest is indicated.1,3,5 This course of action prevents the misuse of antibiotics, thereby decreasing the development of antibiotic-resistant bacteria and the incidence of adverse effects associated with antibiotic use.
Bacterial meningitis is potentially life-threatening, with rapid deterioration and high mortality rates (as high as 40%). Thus, the initiation of empiric antibiotics within 30 minutes of suspected bacterial meningitis is the standard of care (for patients younger than 1 month of age, ampicillin plus an aminoglycoside or third-generation cephalosporin; for patients 1 month of age and older, vancomycin plus a third-generation cephalosporin).1,3
Enteroviruses, the primary cause of viral meningitis, can be detected reliably via real-time PCR analysis in approximately 3 hours. Enterovirus PCR has a sensitivity of 86% to 100% and a specificity of 92% to 100%. Enterovirus PCR results that return positive in a timely manner are associated with shorter hospital stays and with a reduced duration of antibiotics use.1,5,6
In the case described here, the patient was admitted and started on empiric intravenous vancomycin and cefotaxime for suspected partially treated bacterial meningitis. Clinically, the patient’s symptoms resolved without any issues, and she was discharged 72 hours after admission, after CSF, blood, and urine cultures tests returned negative results. Following her discharge, enterovirus PCR test results returned 5 days after her admission, revealing a positive result, confirming the diagnosis of aseptic meningitis.
In retrospect, this patient’s clinical status and CSF findings at the time of admission were more suggestive of viral meningitis than of partially treated bacterial meningitis. Thus, close observation and supportive therapy in lieu of immediate antibiotic therapy might have been a more appropriate approach. However, concern about the validity of the CSF test results in the context of antibiotic pretreatment prompted the immediate initiation of empiric antibiotics.
Yasmina Ahmed, BA, is a fourth-year medical student at the University of Nevada School of Medicine in Las Vegas.
Pisespong Patamasucon, MD, is a pediatric infectious disease specialist and professor of pediatrics at the University of Nevada School of Medicine in Las Vegas.
Jack Lazerson, MD, is a professor emeritus at the University of Nevada School of Medicine in Las Vegas.
References
1. Bamberger DM. Diagnosis, initial management, and prevention of meningitis. Am Fam Physician. 2010;82(12):1491-1498.
2. Sáez-Llorens X, McCracken GH Jr. Meningitis. In: Gershon AA, Hotez PJ, Katz SL. Krugman’s Infectious Diseases of Children. 11th ed. St Louis, MO: Mosby; 2004:373-390.
3. Tunkel AR, Hartman BJ, Kaplan SL, et al. Practice guidelines for the management of bacterial meningitis. Clin Infect Dis. 2004;39(9):1267-1284.
4. Nigrovic LE, Malley R, Macias CG, et al; American Academy of Pediatrics, Pediatric Emergency Medicine Collaborative Research Committee. Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis. Pediatrics. 2008;122(4):726-730.
5. Steiner I, Budka H, Chaudhuri A, et al. Viral meningoencephalitis: a review of diagnostic methods and guidelines for management. Eur J Neurol. 2010;17(8):999-1009, e55-e57.
6. Archimbaud C, Chambon, M, Bailly JL, et al. Impact of rapid enterovirus molecular diagnosis on the management of infants, children, and adults with aseptic meningitis. J Med Virol. 2009;81(1):42-48.