Benzocaine-induced Methemoglobinemia Research Articles

An Intubated Patient with a Blue Tongue: Don’t Forget Benzocaine-Induced Methemoglobinemia

Benzocaine-induced methemoglobinemia is a rare but lifethreatening condition. An 83-year-old female with history of congestive heart failure underwent a transcatheter aortic valve implantation..

Benzocaine-Induced Methemoglobinemia. A Clinical Case

The article describes a clinical case of the development of a severe, life-threatening methemoglobinemia in a patient with a dystrophic form of congenital epidermolysis bullosa while receiving a drug containing benzocaine. The current data on classification, pathogenesis, clinical course and methods for treating this state has been presented. Many substances and drugs that are methemoglobin formers are widespread and can cause chronic methemoglobinemia. Acute severe methemoglobinemia is accompanied by life-threatening organ disorders. In some cases, it may be difficult to diagnose methemoglobinemia due to the polymorphism of the clinical picture, the need for laboratory confirmation of the diagnosis, which may be underperformed in the absence of adequate alertness. The presented clinical case will be useful for doctors of various specialties.

Benzocaine-Induced Methemoglobinemia

Benzocaine-Induced Methemoglobinemia

A Case Report of Benzocaine-Induced Methemoglobinemia

Methemoglobinemia is a serious medical condition characterized by the disrupted binding of oxygen to iron on hemoglobin, with a consequent impaired oxygen delivery to body tissues. Various drugs including the local anesthetics such as benzocaine can cause acquired methemoglobinemia. The reported case describes methemoglobinemia that occurred in association with the use of topical benzocaine spray and lozenges in a previously healthy 51-year-old female who had undergone colon surgery to remove a bleeding polyp. Pulse oximetry revealed the patient was hypoxic and a measured methemoglobin (MetHB) serum concentration was 32.4%, well above the normal of less than 2%. Treatment with intravenous methylene blue resulted in a rapid improvement in the patient’s respiratory status. The case emphasizes the need for practitioners to appreciate that topical benzocaine products can cause potentially fatal methemoglobinemia.

Drug-Induced Methemoglobinemia: a Case Report and Review of Literature

Drugs, including those used during diagnostic procedures, can have adverse effects and potentially serious side-effects, especially in complicated patients with significant comorbidity. Benzocaine is frequently used as an oropharyngeal anesthetic agent during bronchoscopy, transesophageal echocardiography, and upper GI endoscopy and can cause methemoglobinemia, a potentially life-threatening event if not diagnosed and treated quickly. Co-oximetry is the gold standard for the diagnosis of methemoglobinemia and can quantitate blood levels, which in turn correlate with the clinical presentation and the urgency for treatment. Methylene blue is the treatment of choice for methemoglobinemia. In this case report we discuss the pathophysiology, the clinical presentation, the diagnosis, and the treatment of benzocaine-induced methemoglobinemia.

Evaluation and Management of Acquired Methemoglobinemia Associated with Topical Benzocaine Use

Benzocaine is a widely used topical oropharyngeal anesthetic and has been reported to cause methemoglobinemia. We discuss benzocaine-induced methemoglobinemia and review the causes, presentation, and management of this serious complication. Treatment with methylene blue will result in reversal of methemoglobinemia and clinical recovery in most cases but needs to be used at appropriate doses in carefully selected individuals. Physicians who perform procedures involving the application of benzocaine for topical anesthesia need to rapidly identify and treat methemoglobinemia to avoid significant associated morbidity and mortality.

Methemoglobinemia-Induced Acute Kidney Injury

IntroductionMethemoglobinemia refers to the presence of increased levels of methemoglobin (Fe3+) in the blood. Methemoglobinemia can cause cyanosis, dyspnea, fatigue, seizure, arrhythmia, coma, and even death. Although methemoglobinemia is shown to cause acute kidney injury in experimental settings, human case reports are exceedingly rare. In addition, morphological features of methemoglobinemia-induced renal disease in humans remain undefined.Case PresentationA 76-year-old man with a history of chronic obstructive pulmonary disease underwent bronchoscopy following local anesthesia with a benzocaine spray. The patient developed benzocaine-induced methemoglobinemia and acute renal failure. Urinalysis disclosed numerous dysmorphic erythrocytes, erythrocyte casts, and granular casts. Urine protein excretion was approximately 1.1 g/day. Serologic tests were negative. Renal biopsy demonstrated minor glomerular abnormalities, severe acute tubular necrosis, and numerous erythrocyte casts in the tubules. Despite supportive care, renal function deteriorated necessitating hemodialysis. Four months later, the patient remained on hemodialysis. To exclude a superimposed pathology, renal biopsy was repeated and showed numerous erythrocyte casts in the tubules and severe tubular damage.ConclusionMethemoglobinemia can cause acute kidney injury in humans. Morphological features resemble those observed in methemoglobin-induced acute kidney injury in experimental settings. This case calls for a heightened awareness of potential adverse effects of methemoglobinemia on renal function.

Benzocaine-Induced Methemoglobinemia in the Pediatric Population

TEETHING TYPICALLY BEGINS around 4 to 6 months of age and can last through toddlerhood. When teeth begin to erupt, the gums become swollen at the location of the future tooth, causing pain and irritation ( Ricci and Kyle, 2009 Ricci S.S. Kyle T. Maternity and pediatric nursing. Wolters Kluwer, Philadelphia, PA2009 Google Scholar ). An infant's pain may be minimal for some episodes of teething, while other episodes can cause significant discomfort. The discomfort can lead to fussiness, inability to sleep, and decreased oral intake ( Ricci and Kyle, 2009 Ricci S.S. Kyle T. Maternity and pediatric nursing. Wolters Kluwer, Philadelphia, PA2009 Google Scholar ). Parents attempt to make their infant as comfortable as possible throughout this process, commonly turning to home remedies, teething rings, and over the counter topical anesthetics and oral medications.

Benzocaine-induced methemoglobinemia in an acute-exposure rat model

Tricaine methanesulfonate, a sedative for temporarily immobilizing fish, has a 21-day withdrawal time. Benzocaine has been proposed as an alternative sedative because a withdrawal period may not be required. Since benzocaine is known to induce methemoglobinemia, the potential for orally administered benzocaine to induce methemoglobin was assessed in rats. Sprague–Dawley rats were given a single gavage administration of 64mg benzocaine hydrochloride per kg bw and then euthanized at intervals up to 120min. Plasma levels of benzocaine were relatively low at all times, whereas methemoglobin peaked at 24min. Additional rats were orally gavaged with 0–1024mg benzocaine hydrochloride per kg bw and euthanized after 24min. Plasma levels of benzocaine increased from 0.01μM at 2mg per kg bw to 2.9μM at 1024mg per kg bw. Methemoglobin levels did not differ from controls at doses up to 32mg per kg bw in females and 64mg per kg bw in males, whereupon the value increased to ∼80% at 1024mg per kg bw. These data were used to estimate the potential impact of benzocaine residues in fish and suggest that the consumption of fish treated with benzocaine hydrochloride will not cause methemoglobinemia in humans.

Presumptive Benzocaine-Induced Methemoglobinemia in a Slender-Tailed Meerkat (Suricata Suricatta)

An 8-yr-old castrated male slender-tailed meerkat (Suricata suricatta) was anesthetized for physical examination and dental prophylaxis. To facilitate intubation, two short bursts of benzocaine spray were applied topically to the glottis. Shortly thereafter, the meerkat developed a muddy, blue-gray mucous membrane color and low oxygen saturation readings measured via pulse oximetry. Despite positive pressure ventilation and treatment with doxapram, the cyanosis and hypoxemia did not improve. Blood collected during the procedure was noticeably dark brown and a clinical diagnosis of methemoglobinemia was made. Because of persistent cyanosis and prolonged recovery, the meerkat was anesthetized a second time to facilitate treatment for methemoglobinemia via a slow intravenous bolus of methylene blue and subcutaneously administered dextrose. Within 20 min, the tongue and gingival color normalized. This is the first report of methemoglobinemia in this species. Although it is commonly used in small animal practice and in humans undergoing certain endoscopic procedures, and present in numerous over-the-counter preparations, the risk of topical benzocaine inducing methemoglobinemia is well described. Administration of topical benzocaine in all mammalian species, particularly small patients, should be done with caution. If it is utilized in zoo practice, clinicians are encouraged to administer benzocaine judiciously to avoid accidental overdose, and be familiar with the signs of methemoglobinemia and its treatment.

Banning Benzocaine: Of Bananas, Bureaucrats, and Blue Men

Banning Benzocaine: Of Bananas, Bureaucrats, and Blue Men

Topical Benzocaine-induced Methemoglobinemia in the Pediatric Population

Topical benzocaine is an anesthetic agent that is often used before procedures and clinical tests, such as esophagoscopy, bronchoscopy, and endotracheal intubation. However, a potential deadly condition known as methemoglobinemia can occur with this agent. It causes the oxidation of hemoglobin to methemoglobinemia to occur more rapidly than the reduction of methemoglobin back to hemoglobin. Certain congenital and clinical conditions that affect oxygen delivery can increase the patient's risk of having methemoglobinemia develop with the use of benzocaine. Topical benzocaine-induced methemoglobinemia can occur in the pediatric population. Prompt management with intravenous methylene blue should be initiated for reversal.

Topical Benzocaine-induced Methemoglobinemia in the Pediatric Population

Topical Benzocaine-induced Methemoglobinemia in the Pediatric Population

Benzocaine-Induced Methemoglobinemia Based on the Mayo Clinic Experience From 28 478 Transesophageal Echocardiograms

The potentially life-threatening condition of methemoglobinemia is characterized by cyanosis, low pulse oximetric readings, and normal arterial Po(2) values. Acquired methemoglobinemia has been linked to the use of the topical anesthetic benzocaine in endoscopic procedures, including transesophageal echocardiography (TEE). Yet, the incidence of benzocaine-induced methemoglobinemia with TEE and the clinical factors associated with its development are unclear. All cases of methemoglobinemia complicating TEE at our institution (from January 1, 1999, to July 1, 2006) were identified by a comprehensive review of medical records and echocardiography and pharmacy databases. During 90 months among 28 478 TEEs, 19 cases of methemoglobinemia were identified, with a mean +/- SD methemoglobin level of 32% +/- 15%. All patients were cyanotic, with low oxygen saturations. Eighteen of 19 patients received methylene blue (mean +/- SD dose, 1.3 +/- 0.4 mg/kg of body weight), with resolution of symptoms and signs. One of 19 cases resolved spontaneously. Compared with a random sample of 190 patients undergoing TEE, the age, sex, body mass index, left ventricular systolic function, and dose of sedation (midazolam hydrochloride, fentanyl citrate, or both) were similar in the 2 groups. However, study patients who developed methemoglobinemia were more likely to be hospitalized (89.5% vs 57.6%, P =.005), be anemic (84.2% vs 44.7%, P =.002), and have active systemic infection (68.4% vs 6.8%; P < .001) at the time of TEE compared with the random control cohort. In a large series of patients undergoing TEE, the incidence of methemoglobinemia is low (1 case per 1499 [0.067%; 95% confidence interval, 0.040%-0.100%]) and has a good outcome if promptly recognized and treated. Clinical factors associated with the development of methemoglobinemia include sepsis, anemia, and hospitalization. Minimizing or avoiding the use of benzocaine in these patients is recommended.

Benzocaine-induced Methemoglobinemia

Benzocaine-induced Methemoglobinemia

Methemoglobinemia Following Transesophageal Echocardiography: A Case Report and Review

Benzocaine (ethyl aminobenzoate) is a topical anesthetic widely used for oropharyngeal anesthesia prior to transesophageal echocardiography (TEE). Topical anesthetics have been reported to cause methemoglobinemia, but this adverse event is extremely rare and has not been listed as one of the possible complications of TEE. However, recently the number of published case reports of TEE-associated methemoglobinemia has increased. Since its first description in 1950, 65 cases of methemoglobinemia have been reported including a recent report of five cases from a single center. Physicians who are not familiar with the association of TEE with benzocaine-induced methemoglobinemia may not recognize the idiosyncratic and often nonspecific characteristic of this condition. Recognition is critical, however, since left untreated methemoglobinemia can lead to cardiopulmonary compromise, neurological sequelae, and even death. The current report documents an additional case of TEE-associated methemoglobinemia from a high-volume (8000 cases /year including 400-450 TEE/year) echo lab. A review of the literature suggests that this complication may be more prevalent, than generally appreciated. This case report emphasizes the importance of appropriate dose, recognition, and the treatment of this entity to cardiologists performing TEE.

Benzocaine-induced Methemoglobinemia

A case is reported in which a patient developed methemoglobinemia-induced cyanosis while under general anesthesia during surgery for multiple fascial space infections. The cause of methemoglobinemia was 20% benzocaine spray used for local anesthesia before intubation. Acutely developing methemoglobinemia is infrequently encountered in clinical practice. When confronted with cyanosis in the absence of cardiac or pulmonary disease, one must seriously consider the diagnosis of methemoglobinemia. The etiology of methemoglobinemia, the causative agents, the diagnosis, and the emergency treatment required are discussed.

Methemoglobinemia revisited: An important complication after transesophageal echocardiography

Methemoglobinemia induced by the use of benzocaine-containing topical anesthetics is a rare, but potentially lethal complication after transesophageal echocardiography (TEE). We report a patient who developed methemoglobinemia after TEE. A review of the literature was performed and the majority of cases of benzocaine-induced methemoglobinemia reported thus far have occurred in patients undergoing TEE, endotracheal intubation, esophagogastroduodenoscopy, and bronchoscopy. All of these procedures have become more frequent than before, and there is a need to reemphasize the potential problem and to reconsider the need for further use of topical anesthetics.

Methemoglobinemia as a Complication of Topical Anesthesia During Bronchoscopy

Abstract:Methemoglobinemia, although uncommon, is a potentially life-threatening complication of topical anesthetics. We describe a case of a 46-year-old man developed a severe methemoglobinemia after routine bronchoscopy. After administration of 1 mg/kg intravenous methylene blue, the patient's con

Benzocaine-Induced Methemoglobinemia: A Condition of which all Endoscopists Should Be Aware

Methemoglobinemia is a rare complication that can occur with the use of benzocaine-containing compounds. Two cases of methemoglobinemia are reported, and the pathophysiology and treatment of methemoglobinemia are reviewed. Both patients received topical 20% benzocaine spray before endoscopy. Immediately following the procedure, there was a reduction in O2 saturation assessed by pulse oximetry that was refractory to O2 therapy. Dramatic peripheral and central cyanosis developed. O2 saturation measured by pulse oximetry ranged from 83% to 87% on O2 by nasal prongs and 100% O2 by a nonrebreathing mask. Both patients were mildly confused and one patient complained of a significant headache. The diagnosis of methemoglobinemia was considered and arterial blood gas sampling was performed. In both patients, the arterial blood had a chocolate brown colour. A methemoglobin level of 48% and 18% was noted in patient 1 and patient 2, respectively. Both patients were treated with methylene blue, resulting in a significant improvement with gradual normalization of their O2 saturation within 10 min to 30 min. The use of benzocaine spray may not markedly alter the patient's perception of endoscopy and thus, the routine use of these agents should be questioned. If such agents are used, the physician must be aware of this association to prevent a delay in the diagnosis and management of this rare, but potentially lethal, condition.