WHEN TO TREAT ã…¡ Diagnosis of bacterial meningitis may be difficult as symptoms are similar in many other illnesses. A classic triad of fever, neck stiffness, and altered mental status is seen in about 40% of patients, although it is more common in the elderly and in those with pneumococcal meningitis. Rapidly evolving petechial or purpuric rash may indicate meningococcal disease.
Once there is clinical suspicion of acute bacterial meningitis, you are placed in an isolation room to protect staff and others from infection. Additionally, a mask may be placed over your nose and mouth to further prevent the spread of infection.
WHEN TO INVESTIGATE
Immediately obtain blood and CSF samples for culture and initiate empiric antimicrobial therapy. Delays in blood culture or lumbar puncture may result in delayed diagnosis. If diagnosis and initiation of therapy are delayed, risk of morbidity and mortality increases. Do not delay empiric therapy if lumbar puncture delayed. Diagnosis of meningitis based on clinical suspicion and identification of causative bacteria from any of (1) CSF cultures (positive in up to 80% of patients not pretreated with antibiotics), (2) Blood culture (positive in 50%-90% in patients no pretreated with antibiotics and 30%-70% in patients receiving pretreatment).
- Organism identified from CSF by culture.
- Patient has at least 1 of the following signs or symptoms with no other recognized cause: fever (> 38 degrees C), headache, stiff neck, meningeal signs, cranial nerve signs, or irritability. And at least 1 of the following...
- Increased white cells, elevated protein, and/ or decreased glucose in CSF.
- Organisms seen on Gram’s stain of CSF.
- Organisms cultured from blood.
- Positive antigen test of CSF, blood, or urine.
- Diagnostic single antibody titer(IgM) or 4-fold increase in paired sera (IgG) for pathogen.
- In patients ≤ 1 year old, has at least ≥ 2 of following signs or symptoms without other cause: fever (> 38 degrees C), headache, stiff neck, meningeal signs, cranial nerve signs, or irritability. And at least ≥ 1 of following...
- Increased white cells, elevated protein, and decreased glucose in CSF.
- Positive Gram’s stain of CSF.
- Organism identified from blood by culture or nonculture-based testing method, performed for clinical diagnosis or treatment, not surveillance.
- Diagnostic single antibody titer (IgM) or 4-fold increase in paired sera (IgG) for organism.
MANAGEMENT
EMPIRIC ANTIBIOTICS ― Delays in treatment are associated with an increased mortality. For community-acquired bacterial meningitis, empiric treatment in patients with normal renal function often includes...- For adults < 50 years old, ceftriaxone 2 g IV every 12 hours plus vancomycin 15-20 mg/kg IV every 8-12 hours.
- For adults > 50 years old or immunocompromised patients, ceftriaxone 2 g IV every 12 hours plus vancomycin 15-20 mg/kg IV every 8-12 hours plus ampicillin 2 g IV every 4 hours.
- Add acyclovir 10 mg/kg IV every 8 hours for all patients until herpes simplex meningoencephalitis is ruled out.
For postsurgical bacterial meningitis, or meningitis associated with head trauma or shunt, empiric treatment often includes coverage for methicillin-resistant Staphylococcus aureus (MRSA) and aerobic gram-negative organisms, such as Pseudomonas spp. and Enterobacteriaceae. Infectious Diseases Society of America recommends vancomycin 15-20 mg/kg IV every 8-12 hours plus either ceftazidime 2 g IV every 8 hours or cefepime 2 g IV every 8 hours. A definitive therapy and the duration of therapy should be based on cerebrospinal fluid (CSF) culture results (see Table 1).
- H. influenzae - 7 days.
- N. meningitidis - 7 days.
- S. pneumoniae - 10-14 days.
- S. agalactiae - 14-21 days.
- Aerobic gram-negative bacilli - 21 days.
- L. monocytogenes - at least 21 days.
- Unspecified bacterial meningitis - 10-14 days.
- H. influenzae meningitis - 7-14 days.
- Pneumococcal meningitis - 10-14 days.
- Meningococcal meningitis - 5-7 days.
- Listeria meningitis - 21 days.
- Gram-negative bacilli and Pseudomonas meningitis - 21-28 days.
| Table (1). Empiric Therapy for Adults with Bacterial Meningitis (Infectious Diseases Society of America [IDSA] recommended first-line therapy for bacterial meningitis) | |||
|---|---|---|---|
| Patient Characteristics | Common Pathogens | Antibiotic Regimen | Total Daily Dosages and Dosing Intervals |
| Age < 50 years | Neisseria meningitis | Vancomycin plus either ceftriaxone or cefotaxime — Some experts would add rifampin if dexamethasone is also given | Vancomycin 30-45 mg/kg every 8-12 hours Ceftriaxone 4 g every 12-24 hours Cefotaxime 8-12 g every 4-6 hours |
| Streptococcus pneumoniae |
|||
| Age > 50 years | S. pneumoniae | Vancomycin plus ampicillin plus either ceftriaxone or cefotaxime |
Vancomycin 30-45 mg/kg every 8-12 hours Ampicillin 12 g every 4 hours Ceftriaxone 4 g every 12-24 hours Cefotaxime 8-12 g every 4-6 hours |
| N. meningitidis | |||
| Listeria monocytogenes | |||
| Aerobic gram-negative bacilli | |||
| Post neurosurgery, penetrating head trauma, or if CSF shunt present | Coagulase-negative staphylococci (especially Staphylococcus epidermis) | Vancomycin plus any of cefepime, ceftazidime, or meropenem | Vancomycin 30-45 mg/kg every 8-12 hours Cefepime 6 g every 8 hours Ceftazidime 6 g every 8 hours Meropenem 6 g every 8 hours |
| Aerobic gram-negative bacilli (including Pseudomonas aeruginosa) | |||
| Propionibacterium acnes (for CSF shunt infections) | |||
| Staphylococcus aureus | |||
PREVENTION
Preventive measures recommended by the Centers for Disease Control and Prevention for meningococcal meningitis include droplet precautions for hospitalized patients as soon as diagnosis is suspected through the first 24 hours of antimicrobial therapy and chemoprophylaxis for close contacts of patients with confirmed meningococcal meningitis. Closer than 3 feet for > 8 hours or those exposed to oral secretions and exposed during the 7 days prior to and 1 day after the start of antibiotics. Ciprofloxacin 500 mg single dose is prescribed unless there is concern for quinolone-resistant Neisseria meningitidis (rare but has been reported).REFERENCES
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Overview | Meningitis (bacterial) and meningococcal septicaemia in under 16s: recognition, diagnosis and management | Guidance | NICE. www.nice.org.uk [online] Available at: https://www.nice.org.uk/guidance/cg102
Smith, L. (2019). Management of Bacterial Meningitis: New Guidelines from the IDSA. American Family Physician, [online] 71(10), p.2003. Available at: https://www.aafp.org/afp/2005/0515/p2003.html
Chaudhuri, A., Martin, P.M., Kennedy, P.G.E., Andrew Seaton, R., Portegies, P., Bojar, M. and Steiner, I. (2008). EFNS guideline on the management of community-acquired bacterial meningitis: report of an EFNS Task Force on acute bacterial meningitis in older children and adults. European Journal of Neurology, 15(7), pp.649–659
McGill, F., Heyderman, R.S., Panagiotou, S., Tunkel, A.R. and Solomon, T. (2016). Acute bacterial meningitis in adults. The Lancet, [online] 388(10063), pp.3036–3047. Available at: https://www.sciencedirect.com/science/article/pii/S0140673616306547
Tunkel, A.R., Hasbun, R., Bhimraj, A., Byers, K., Kaplan, S.L., Scheld, W.M., van de Beek, D., Bleck, T.P., Garton, H.J.L. and Zunt, J.R. (2017). 2017 Infectious Diseases Society of America’s Clinical Practice Guidelines for Healthcare-Associated Ventriculitis and Meningitis. Clinical Infectious Diseases, 64(6), pp.e34–e65. Available at: https://academic.oup.com/cid/article/64/6/e34/2996079
Heckenberg, S.G.B., Brouwer, M.C. and van de Beek, D. (2014). Chapter 93 - Bacterial meningitis. [online] ScienceDirect. Available at: https://www.sciencedirect.com/science/article/pii/B9780702040887000936?via%3Dihub