To Tap, or Not To Tap, That Is the Question

Editor’s Note: Dr. Mobeen Rathore is a professor and Associate Chair in pediatrics at the University of Florida; Director, University of Florida Center for HIV/AIDS Research, Education and Service (UF CARES); Chair of Infection Prevention and Control Committee at Baptist Health System; and Hospital Epidemiologist and Chief of Pediatric Infectious Diseases and Immunology at Wolfson Children’s Hospital. He served as a valued member of the Pediatrics in Review editorial board from 2011 to 2020.

If meningitis is part of your differential diagnosis, a lumbar puncture (LP) is necessary, and the answer is to tap.

Management of bacterial meningitis and neonatal sepsis were perhaps the two most important infectious disease conditions that pediatric residents had to be well versed in for the inpatient setting. Performing a clean LP was a badge of honor, and everyone heard the news about a “bloody tap.”

That has all changed in the past three decades. Cases of Haemophilus influenzae type b (Hib) infections plummeted in October 1990 after the introduction of conjugate Hib vaccine for infants starting at two months of age.¹ A decade later, with the introduction of conjugate Streptococcus pneumoniae (Sp) vaccine for infants, cases of Sp meningitis also dropped significantly.² In addition, with universal Group B Streptococcus (GBS) screening and prophylaxis during pregnancy, early onset GBS sepsis and meningitis have plummeted.³ Currently,  it is the children who are unvaccinated and under vaccinated against Hib and Sp who are the ones primarily at risk for bacterial meningitis. Other risk factors for meningitis (including recurrent meningitis)  include complement C3 deficiency (Sp), anatomical defects such as basilar skull fracture (nasopharyngeal flora), dermal sinus defect (skin flora), inner and middle ear defects, cochlear implant, and asplenia (encapsulated organisms).

As a result of the decrease in incidence of meningitis, LP is a lost art, and “bloody tap” is commonplace if not almost an expectation. Any correction formulae used to assess a bloody tap are essentially useless.

The June Pediatrics in Review (PIR) article, "Meningitis in Children: Still a Can’t-Miss Diagnosis," provides a good and timely overview of meningitis in children (10.1542/pir.2023-006013).

Clinical manifestations can be subtle, especially in the younger infants. Some of the important points in the management of meningitis include appropriate evaluation of the cerebrospinal fluid (CSF). While culture and Gram stain remain the standard, CSF analysis, especially with a clean CSF specimen, can be extremely valuable. Newer molecular techniques have a proven benefit, especially in partially treated meningitis. Review of CSF protein and glucose are useful. Glucose should be compared to blood glucose level. Anything below 40 mg/ dL should be of concern for meningitis; however, any level that is 50% lower than blood glucose level is suggestive of meningitis.

There is also the question of repeat LP, especially in neonatal meningitis. Decades ago, neonates had a repeat LP early in the course of treatment (in the first 24–48 hours) and at the end of antibiotic therapy. Now most experts do not recommend end of therapy LP. However, a repeat LP at 24–48 hours is still recommended by most infectious diseases experts.

Most of the current guidance for the management of meningitis is, by and large, based  on expert opinion and decades of experience.

Use of empiric antibiotic therapy is the gold standard and should never be unnecessarily delayed if meningitis is a consideration. The aforementioned article in this issue of PIR addresses antibiotic use. Some points to remember are that GBS is universally penicillin susceptible, so either penicillin or ampicillin (favored by most) remain effective. Cefotaxime was the antibiotic of choice for specific treatment of neonatal Gram-negative meningitis; however, cefotaxime shortage has forced use of extended spectrum cephalosporins such as Cefepime or Ceftazidime in the treatment of neonatal Gram-negative meningitis. For non-neonates, Ceftriaxone is the preferred cephalosporin.

Hib meningitis is rare. While selecting antibiotics for treatment of Hib meningitis, it is important to wait for susceptibility results, even in β-lactamase negative Hib isolates. A β-lactamase negative Hib isolate can still be resistant to ampicillin because of uncommon β-lactamase negative ampicillin resistant (BLNAR) strains. Before switching to ampicillin, review of the full susceptibility pattern is essential.⁴

One last point: fever is part of meningitis. When dexamethasone is used, fever may return once dexamethasone is stopped. However, this is likely a “rebound fever”  and not secondary fever, which is associated with complications of meningitis.⁵

Meningitis still remains a matter of grave concern in children. It is now an uncommon condition but something that remains a top priority for pediatricians to rule out in febrile infants, especially those who are unimmunized or under immunized. It is also still one of the major reasons for pediatricians getting sued.⁶

If you are considering meningitis in your differential, performing an LP is the only way to exclude meningitis.

References

1. Rathore MH, Dick M, Buckner P, et al. Haemophilus influenzae type b invasive disease in urban and rural children: immunization patterns and prevalence of disease. South Med J. 1994;87(11):1083–1087
2. Abuelreish M, Subedar A, Chiu T, et al. Increase in invasive pneumococcal Disease in children associated with shortage of heptavalent pneumococcal conjugate vaccine. Clinical Pediatr. 2007;46(1):53–58
3. Schrag SJ, Zywicki S, Farley MM, et al. Group B Streptococcal disease in the era of intrapartum antibiotic prophylaxis. N Engl J Med. 2000;342:15–20
4. Doern GV, Brueggemann AB, Pierce HP, et al. Antibiotic resistance among clinical isolates of Haemophilus influenzae in the United States in 1994 and 1995 and detection of β-lactamase positive strains resistant to amoxicillin-clavulanate: results of national multi-center surveillance study. Antimicrob Agents Chemother. 1997;41:292–297
5. Lin TY, Nelson JD, McCracken GH. Fever during treatment of bacterial meningitis. Pediatr Infect Dis. 1984;3(4):319–322
6. Caroll AE, Buddenbaum JL. Malpractice Claims Involving Pediatricians: Epidemiology and Etiology. Pediatrics. 2007; 120(1):10-17).