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Three Part Question

In [patients with non penetrating corneal abrasion] is [tetanus toxoid booster] necessary to [prevent clinical tetanus infection] ?

Clinical Scenario

A 44 year old man presents to the emergency department with a foreign body sensation in his right eye. Fluorescein examination reveals a piece of grit. After removal there is a small corneal abrasion with no evidence of perforation. The patient has had a primary course of tetanus antitoxin and thinks his last tetanus booster was less than ten years ago but is not sure. You wonder if the patient requires a tetanus booster to reduce any risk from the abrasion.

Search Strategy

Medline 1966-10/02 using the OVID interface.
(exp tetanus OR exp tetanus antitoxin OR exp tetanus toxin OR exp tetanus toxoid OR tetanus.mp) AND (exp Cornea OR corneal abrasion.mp OR exp Eye Injuries OR exp Eye Foreign Bodies OR exp Wounds, Nonpenetrating)

Search Outcome

Altogether 31 papers found of which 21 were irrelevant or of insufficient quality for inclusion. Five papers on cases of tetanus following penetrating eye injuries, one paper on tetanus from an eyelid injury and there papers on management of ocular animal bite injuries were excluded as not directly relevant. The remaining paper is shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Benson WH et al, 1993, USA	Unimmunized mice Animal model surgically injecting live C tetani or tetanus toxin into mice cornea	(Prospective) Experimental animal model	Incidence of clinical tetanus following: - corneal abrasion -corneal penetration -corneal perforation	0/9 0/9 10/27	Animal model C tetani organisms and toxin used pure – not representative of usual clinical mixed flora
			Incidence in immunized mice	0/42

Comment(s)

The only relevant paper found was an experimental animal study. Unlike skin, corneal epithelium does not have an underlying blood supply (receiving nutrients from the aqueous humor) and often shows substantial healing within 6 hours of injury. Criteria for deciding if a corneal abrasion is tetanus prone or not should therefore probably be different than that for standard skin abrasions. Finally there are no case reports in the literature of clinical tetanus developing from a simple corneal abrasion. In clinical practice it should be remembered that there may be public health benefits in encouraging tetanus prophylaxis whenever the opportunity arises.

Clinical Bottom Line

There is no clinical reason to provide tetanus prophylaxis in the emergency department following superficial corneal abrasions with no evidence of perforation, infection or devitalized tissue.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Benson WH, Snyder IS, Granus V, et al. Tetanus prophylaxis following ocular injuries. J Emerge Med 1993;11:677-83.