Accidental injection of 2% chlorhexidine gluconate instead of an anesthetic agent: A case report.

We report a case where 2% chlorhexidine (CHX) gluconate was mistaken for an anesthetic solution and infiltrated into the buccal vestibule during routine root canal treatment. Accidentally, 2% CHX gluconate solution was injected in the right upper buccal vestibule (16) of a 23-year-old male during routine root canal treatment. The patient experienced pain and a burning sensation over the injected area shortly after injection. Swelling with mild extraoral redness over the right cheek area was observed clinically. The patient was immediately administered dexamethasone intramuscularly, and was prescribed antibiotics, analgesics, and antihistamines. The patient complained of a loss of sensation over the right cheek by the 15(th) day. The swelling reduced gradually over a period of 15 days. Reversal of sensation was attained after 35 days.

INTRODUCTION

Endodontic mishaps are unfortunate accidents that occur during treatment, some owing to inattention to detail, others being very unpredictable. Among all types of mishaps mentioned in the literature, large percentages of them are irrigant-related mishaps.[1] Sodium hypochlorite accidents are the most commonly encountered mishaps in endodontics and have been very often reported in literature.[2]

Mishaps related to CHX accidents are rare in endodontic literature, although several in vitro and animal studies have evaluated the cytotoxic nature of CHX.[3]

We present a case report of accidental injection of 2% CHX gluconate in the buccal vestibule area, instead of a local anesthetic (LA) solution.

CASE REPORT

A 23-year-old male reported to the Department of Conservative Dentistry and Endodontics, Sri Aurobindo College of Dentistry, Sri Aurobindo Institute of Medical Sciences, Indore, Madhya Pradesh, India, seeking dental treatment for spontaneous pain in right upper first molar (16). After clinical and radiographic examination, a diagnosis of irreversible pulpitis was established. Root canal therapy was started with the patient's consent. At the first visit, access cavity preparation with standard protocol of irrigation and debridement was performed by the resident. Because the patient had reported during the closing hours of the dental office, he was called for a second visit the next day for biomechanical preparation and obturation of the upper right first molar.

At the second visit, the patient complained of pain in the mesiobuccal root canal during instrumentation. Resident infiltrated LA in the upper right buccal vestibule area assuming incomplete pulp debridement. The patient immediately complained of mild discomfort in the injected area. The patient was reassured and the biomechanical preparation was performed in the mesiobuccal canal. Approximately 10 min later, the patient complained of a severe burning sensation and pain in the injected area. Mild swelling was observed in the right cheek area [Figure 1a]. On observing the symptoms and the clinical condition of the patient, the solution in the syringe was checked and found to be 2% CHX (mild mint flavored) (Safe plus, Neelkanth Healthcare Pvt. Ltd, Jodhpur, Rajasthan, India).

Figure 1

(a) Mild extraoral swelling immediately after CHX accident (b) Moderate extraoral swelling and redness involving the right infraorbital region after 24 h

The patient was explained about the mishap and was assured of complete treatment and care until the symptoms resolved. The patient was immediately administered dexamethasone (4 mg) intramuscularly. Antibiotics, analgesics, and antihistamines were prescribed. The patient was advised to report everyday to the dental office, to assess his clinical condition.

The swelling had increased the next day and had involved the right infraorbital region [Figure 1b], but the pain had relatively reduced. There was no improvement in the clinical appearance (extraoral swelling and redness) of the patient on the 4th day of visit. Considering the continuing discomfort the patient was put on oral steroids by the 5th day, dexamethasone 5 mg thrice daily for 3 days, and subsequently dosage was tapered. On the 7th day the pain had subsided completely and the extraoral swelling had substantially reduced. Biomechanical preparation and obturation of the upper right first molar was completed on the same day [Figure 2a and b].

Figure 2

(a) Extensive extraoral swelling and redness of the right side of face on 4th day (b) Substantial reduction in extraoral swelling at 1-week follow-up

Swelling had completely regressed by the 15th day [Figure 3]. Meanwhile, the patient complained of a loss of sensation during shaving in the right cheek area. The patient was reassured about reversal of the sensation and the patient regained the sensation after 35 days. A follow-up of 3 months was maintained to ensure the well-being of the patient.

Figure 3

Complete regression of extraoral swelling after 15 days

DISCUSSION

Although the dental literature provides guidance for safe and effective administration of LA in dental operatory for various invasive procedures,[4] there have been reports of unintended injection of formalin, hydrogen peroxide, and sodium hypochlorite instead of LA. Various reasons have been stated, such as the widespread practice of using LA in bottles, reuse of LA bottles in dental operatory, nonavailability of professionally trained or educated dental assistants, and improper handling techniques.[156]

A survey conducted on responsible handling of LA agent in Indian dental operatory reported injecting other fluids instead of LA as a severe negligent act and highlighted the need for training for responsible handling of fluids in dental operatory.[7]

An endodontic irrigant should be nontoxic when it comes in contact with vital tissues. A potential complication of irrigation is the forced extrusion of the irrigant and debris through the apex. The complication may worsen when an irrigant is infiltrated instead of LA solution, owing to the negligence of the operator or the supporting staff.

CHX accidents have been widely reported in medical literature. Edema of tongue, oral ulcers, and acute pulmonary edema are the adverse effects reported in a case wherein, five babies were accidentally fed with a formula prepared with 0.05% CHX (mistaken for sterile water).[8]

Over the last decades, a wide array of cell lines have been used to evaluate the cytotoxicity of CHX. The exposure of cultured human dermal fibroblasts to CHX at concentrations equal to or greater than 0.005% for 3 h caused cell death.[9]

The abovementioned case report in the field of medicine, and the in vitro study in the field of dentistry provide the necessary information about the cytotoxic nature of CHX. Considering the facts, it can be concluded that in this case the patient must have had severe inflammation, edema, and a moderate amount of necrosis. Though the authors were familiar with the cytotoxic nature of CHX, it was very difficult to recall an accidental injection of CHX instead of LA solution. Considering the available dental literature about the nature of effect of CHX on soft tissues, we decided to prescribe a course of antibiotics, analgesics, antihistamines, and steroids.

The reason for the transient loss of sensation in the right cheek area, experienced by the patient, could be related to the neurotoxicity reported in some animal studies where CHX gluconate was applied directly to the neural tissue of the meninges.[10] A follow-up of 3 months was maintained to ensure the well-being of the patient.

CONCLUSION

The delivery of LA is one of the critical aspects of pain control in dentistry and is practiced widely by dentists. Hence, care must be taken to prevent accidental injection of other chemical agents instead of LA.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.