Severe Methemoglobinemia Complicating Topical Benzocaine Use During Endoscopy in a Toddler: A Case Report and Review of the Literature

Oklahoma State University - Tulsa, Tulsa, Oklahoma, United States
PEDIATRICS (Impact Factor: 5.47). 05/2006; 117(4):e806-9. DOI: 10.1542/peds.2005-1952
Source: PubMed


Severe methemoglobinemia resulting from the use of topical benzocaine has been reported in adults as a rare complication. Here we report a case of severe acquired methemoglobinemia resulting from topical use of benzocaine spray during diagnostic upper gastrointestinal endoscopy in a 3-year-old boy with repeated episodes of hematemesis 3 weeks posttonsillectomy. He developed marked cyanosis and became increasingly agitated immediately after completion of his unremarkable endoscopic procedure, which was performed under intravenous sedation. He did not respond to maximum supplemental oxygen and had increased respiratory effort. His pulse oximetry dropped to 85%, but simultaneous arterial blood-gas analysis showed marked hypoxemia (Po2 = 29%) and severe methemoglobinemia (methemoglobin = 39%). His cyanosis and altered mental status promptly resolved after intravenous administration of methylene blue. In patients with methemoglobinemia, pulse oximetry tends to overestimate the actual oxygen saturation and is not entirely reliable. Posttonsillectomy bleeding is a rare but occasionally serious complication that could occur weeks after the surgery, although it more commonly occurs within the first few days. Physicians should remain aware of the possibility of its late onset. This case illustrates the severity of acquired methemoglobinemia that may result from even small doses of topical benzocaine and highlights the fact that prompt treatment of the disorder can be life saving. We question the rationale for routine use of topical anesthetic spray for sedated upper gastrointestinal endoscopy in children. By bringing the attention of pediatricians to this rare but serious complication, we hope that it will result in its improved recognition and possible prevention.

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    • "It is known that primarily bezocain and many local anaesthetics cause methemoglobinemia. In local procedures such as circumcision the risk of methemoglobinemia due to prilocaine increases when younger the patient and higher the dose administered, as it was in our case (9, 10). In young children, particularly in those younger than 6 months, the underdeveloped enzyme system is one of the factors responsible for the increase in methemoglobin levels. "
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    ABSTRACT: Methemoglobinemia is a disorder characterized by the presence of a higher than normal level of methemoglobin. Prilocaine which is one of the oxidizing local anaesthetics is widely used in many local procedures. The first choice of treatment of complications due to the use of these local anaesthetics is methylene blue, while ascorbic acid is the alternative choice. The side effects of metilen blue restrict its usage in some special conditions. Ascorbic acid is a good alternative drug with limited experience in methemoglobinemia. We present a case of a methemoglobinemia treated with ascorbic acid successfully to emphasize the use of ascorbic acid as an alternative method.
    Full-text · Article · Dec 2013
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    • "could be attributed to advantages such as reduced onset of action (30 seconds), acceptable taste, and effectiveness (Alqareer et al., 2006; Nusstein and Beck, 2003; Primosch and Rolland-Asensi, 2001; Rosa et al., 1999). However, a rare and sometimes lethal complication (i.e., methemoglobinemia) can be induced by topical BZC application (Basra et al., 2006; Dahshan and Donovan, 2006; Hegedus and Herb, 2005; Jaffery and Ananthasubramaniam, 2008; Kwok et al., 2008; Saha et al., 2006; Trapp and Will, 2010). Even though methemoglobinemia is unlikely to happen after the use of low dosages (as in dentistry), it is not impossible, and the development of a topical gel in a controlled release formulation, with a smaller concentration, is advisable to reduce systemic toxicity problems. "
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    ABSTRACT: The aim of the present study was to characterize a liposome-based benzocaine (BZC) formulation designed for topical use on the oral mucosa and to evaluate its in vitro retention and permeation using the Franz-type diffusion cells through pig esophagus mucosa. To predict the effectiveness of new designed formulations during preclinical studies, a correlation between in vitro assays and in vivo efficacy was performed. Liposomal BZC was characterized in terms of membrane/water partition coefficient, encapsulation efficiency, size, polydispersity, zeta potential, and morphology. Liposomal BZC (BL10) was incorporated into gel formulation and its performances were compared to plain BZC gel (B10) and the commercially available BZC gel (B20). BL10 and B10 presented higher flux and retention on pig esophagus mucosa with a shorter lag time, when compared to B20. BZC flux was strongly correlated with in vivo anesthetic efficacy, but not with topical anesthesia duration. The retention studies did not correlate with any of the in vivo efficacy parameters. Thus, in vitro permeation study can be useful to predict anesthetic efficacy during preclinical tests, because a correlation between flux and anesthetic efficacy was observed. Therefore, in vitro assays, followed by in vivo efficacy, are necessary to confirm anesthetic performance.
    Full-text · Article · Dec 2012 · Journal of Liposome Research
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    ABSTRACT: Perioral ulcerated hemangiomas in infants can present a therapeutic challenge to clinicians, especially when associated with severe pain and difficulty feeding. Topical and oral pain medications can be beneficial, but feeding difficulties may still occur while awaiting healing of the ulceration with the use of systemic or topical agents. We present a case of an infant with an ulcerated lip hemangioma treated with an over-the-counter topical sealant in combination with systemic corticosteroid therapy who showed dramatic improvement in pain and tolerance to feeding, resulting in healing of the ulceration.
    No preview · Article · Jan 2012 · Pediatric Dermatology
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