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Three Part Question

In [adults with isolated base of skull fractures] does [the administration of antibiotics] reduce [the incidence of meningitis]?

Clinical Scenario

A 19 year old man attends the Emergency Department having been assaulted in a night club. He has sustained an isolated head injury with no loss of consciousness and is fully alert and orienttated. He has CSF rhinorrhoea secondary to bbase of skull fracture. You wonder whether the administration of antibiotics will reduce the chances of meningitis developing.

Search Strategy

Medline 1966-03/00 using the OVID interface.
[{exp skull fractures OR skull fracture$.mp} OR ({exp fractures OR fracture$.mp} AND {exp skull OR skull.mp)] AND {base.mp OR basilar.mp} AND {exp antibiotics OR antibiotic$.mp}.

Search Outcome

27 papers found of which 25 irrelevant or of insufficient quality for inclusion. The remaining 2 metaanalyses are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Brodie H, 1997 USA	6 studies with data allowing analysis of the incidence of meningitis resulting from posttraumatic CSF fistula. 324 patients of whom 237 received antibiotics and 87 did not.	Metaanalysis	Meningitis rate	2.5% of those receiving antibiotics vs 10% of those that did not	Only 15 cases of meningitis. No formal review of paper quality. No odds ratios or confidence intervvals calculated
Villalobos T et al, 1998, USA	12 studies with data allowing analysis of the effectiveness of antibiotic use in preventing meningitis in basal skull fracture. 1241 patients of whom 719 received antibiotics and 522 did not.	Metaanalysis	Exact odds ratio of meningitis risk (odds of developing meningitis in the untreated vs treated group) in all patients	1.15 (95% CI 0.68 - 1.94)
			Exact odds ratio of meningitis risk in patients with CSF leak	1.34 (95% CI 0.75 - 2.41)

Comment(s)

There are two metaanalyses in this area. One is of high quality2 while the other is not1. Whatever the quality of the metaanalysis the studies that they analyse are poor. A well designed RCT is still needed to answer this question properly.

Clinical Bottom Line

Antibiotics have not been shown to decrease the risk of meningitis in patients with base of skull fractures with or without CSF leaks.

References

1. Brodie HA. Prophylactic antibiotics for posttraumatic cerebrospinal fluid fistulae. A meta-analysis. Arch Otolaryngol Head Neck Surg 1997;123:749-52.
2. Villalobos T, Arango C, Kubilis P et al. Antibiotic prophylaxis after basilar skull fractures: a meta-analysis. Clin Infect Dis 1998;27:364-9.