Massive Sodium Nitrite Overdose: A Case for Prehospital Methylene Blue

Sodium nitrite overdose leads to profound methemoglobinemia and may quickly progress to death. It is an increasingly common method of suicide and is often fatal. Methylene blue is an effective but time-sensitive antidote that has the potential to save lives when administered early. In this case report, we describe a fatal sodium nitrite overdose and the subsequent creation of a prehospital protocol for our large urban Emergency Medical Services system.

Methemoglobinemia and acute ıntravascular hemolysis after naphthalene poisoning in a pediatric patient

Poisoning by naphthalene is uncommon in children. It is a type of poisoning brought on by ingesting, inhaling, or coming into touch with naphthalene-containing substances on the skin. Patients typically present with an initial onset of dark brown urine, watery diarrhea, and bile vomit. The signs include fever, tachycardia, hypotension, and low pulse oximetry readings even with oxygen support. Hemolytic anemia, methemoglobinemia, renal failure, and hyperbilirubinemia are all detected in blood tests. Erythrocyte transfusion, ascorbic acid, methylene blue, and N-acetylcysteine (NAC) therapies are provided to inpatients in addition to symptomatic treatment. We present a 23-month-old male patient who developed methemoglobinemia and acute ıntravascular hemolysis, who was followed up in the intensive care unit for five days due to naphthalene intoxication. Although naphthalene poisoning is very rare, it should be known that it has fatal consequences, and more care should be taken in its use and sale.

Acquired methemoglobinemia due to nitrobenzene poisoning: An unusual acquaintance

Key Clinical Message

Nitrobenzene poisoning is a rare yet life-threatening contention. The ensuing acute methemoglobinemia has a high fatality rate, hence early prompt intervention is required. Methylene blue (intravenous or oral) and ascorbic acid are the cornerstones of management. They must be administered to suspected patients without tardiness.

Abstract

An aromatic organic chemical used in paints and the printing industry is nitrobenzene. Its poisoning causes potentially fatal methemoglobinemia. One aspect of its management involves reducing the iron moiety from its ferric to ferrous form by administering intravenous methylene blue. A 23-year-old man who had deliberately consumed nitrobenzene presented to us with a history of headache and vomiting. He was diagnosed to have methemoglobinemia on the basis of clinical grounds and was managed successfully with intravenous methylene blue and vitamin C.

Shades of Blue: A Case Series of Acquired Methemoglobinemia

Acquired methemoglobinemia (MetHb) is a rare but potentially life-threatening condition that has varied etiology, usually toxin- or drug-induced. We had five cases of acquired methemoglobinemia during six months. Their presentation varied from an asymptomatic state to respiratory distress. The presence of cyanosis and low oxygen saturation (SpO2), despite normal partial pressure of oxygen (PaO2) and chocolate brown-colored blood, were diagnostic clues present in all cases. A high level of methemoglobinemia was detected on arterial blood gas (ABG), confirming the diagnosis. Methylene blue was used as an antidote along with supportive care in symptomatic cases. All these cases of methemoglobinemia recovered completely. A high index of suspicion for methemoglobinemia should be maintained in cases presenting with persistent hypoxia or cyanosis despite normal PaO2.

A Rare Case of Methemoglobinemia after Ifosfamide Infusion in a 3-Year-Old Patient Treated for T-ALL

Methemoglobinemia is a potentially life-threatening, rare condition in which the oxygen-carrying capacity of hemoglobin is diminished. We present the case of a 3-year-old boy treated for T-cell acute lymphoblastic leukemia (T-ALL) who developed methemoglobinemia (MetHb 57.1%) as a side effect of ifosfamide administration. Due to his critical condition, the patient was transferred to the intensive care unit (ICU). The therapy included methylene blue administration, an exchange transfusion, catecholamine infusion, and steroids. Improving the general condition allowed for continuing chemotherapy without ifosfamide and completion of the HR2 block. Vigilance for methemoglobinemia as a very rare side effect should be widespread when using ifosfamide in the treatment protocols.

Methaemoglobinaemia Associated With Mixed Cocaine and Amphetamine Overdose: A Case Report

Methaemoglobinaemia is a rare disorder characterized by increased levels of methaemoglobin, a form of haemoglobin with oxidized iron that cannot efficiently bind oxygen. This leads to inadequate oxygen delivery to tissues with various clinical manifestations from asymptomatic to severe persistent hypoxia, CNS symptoms, and cardiovascular collapse. Acquired methaemoglobinaemia is typically a sudden condition, often resulting from poisoning by specific drugs and compounds, which can potentially have fatal consequences. We present a case of a patient who came with severe methaemoglobinaemia due to intoxication with cocaine and amphetamine.

A rare case of methemoglobinemia in a preterm newborn with unclear etiology

 Cyanosis is a bluish discoloration of the tissues due to increased levels of deoxygenated hemoglobin in capillaries. It is a common finding in newborn infants that can be caused by different diseases, including pulmonary, cardiac, infectious, and hematological disorders. Methemoglobinemia is a rare cause of cyanosis, in which hemoglobin is oxidized, changing its heme iron configuration from the ferrous (Fe2 +) to the ferric (Fe3 +) state, creating methemoglobin (Met-Hb), a form that does not bind oxygen, leading to decreased oxygen delivery to the tissues and cyanosis. We report a rare case of a preterm newborn, who developed cyanosis and worsening hypoxemia on day ten of life, she was found to have elevated Met-Hb percentage in blood gas analysis that required treatment with intravenous methylene blue. Her symptoms resolved after a period of maintenance treatment with oral methylene blue and ascorbic acid, and the etiology of her disease remains unclear.

Recurrent Acute Methemoglobinemia in an Infant With Persistent Gastroenteritis: A Case Report

Acute toxic methemoglobinemia is a rare and fatal condition with increased levels of oxidized hemoglobin. The clinical presentation of methemoglobinemia varies primarily based on total methemoglobin levels in the blood. Patients sometimes have significant cardiopulmonary compromise, but the majority are asymptomatic, with only cyanosis as the most prevalent sign. We report the case of a 41-day-old male who developed methemoglobinemia and persistent gastroenteritis after consumption of well water. In this case, we believe that the recurrence of acute methemoglobinemia episodes resulted from multifactorial reasons such as age at presentation, infection with nitrate-producing organisms, and consumption of nitrite-containing well water. The rationale for prophylactic therapy was implemented, aiming to prevent further episodes. This case report demonstrates the potential of prophylactic therapy as part of the management of infants with recurrent acute methemoglobinemia episodes.

Methemoglobinemia Secondary to Babesia Microti Infection: A Novel Case Report

BACKGROUND

Tick-borne illnesses and methemoglobinemia have not been known to occur together in humans. Few cases have been documented in various animals of methemoglobinemia secondary to tick-borne infections.

CASE REPORT

A 49-year-old man with no significant medical history presented to the emergency department from an urgent care with hypoxia saturating in the mid 80s. He also reported a pruritic rash on his back and right shoulder as well as both of his lower extremities. The rash had been present for 4 days. The patient was tachycardic and hypoxic at 90% but denied shortness of breath. He had cyanosis of the lips and fingertips and multiple erythematous, raised, ovoid lesions on the right shoulder and left lower extremity. Methemoglobin levels were elevated at 26%. He was treated with methylene blue, supplemental oxygen, and empiric doxycycline with improvement in his oxygenation. A tick-borne illness panel later tested positive for Babesia microti infection. His skin lesions resolved with the above described treatment. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Both tick-borne illnesses and methemoglobinemia are typically easily treatable with proper antimicrobial coverage and methylene blue, respectively. The current literature is bare regarding concurrent tick-borne illnesses, specifically babesiosis, and methemoglobinemia. Without knowledge and documentation of a potential link between the two conditions, hypoxia, if found to be due to methemoglobinemia, may be treated adequately, but a potentially life-threatening tick-borne illness may continue to cause damage and disease to the patient if not tested for, identified, and treated.

Out of the Blue: Methemoglobinemia Associated With the Use of Amyl Nitrite in Rush Poppers for Erectile Stimulation

We report a clinical scenario involving a 51-year-old male patient with a history of prediabetes and gastritis who exhibited altered mental status following the consumption of poppers, a supplement containing nitrites, which is used for erectile stimulation. Shortly after the ingestion, the patient experienced convulsions, foaming at the mouth, and subsequently developed altered mental status and severe respiratory distress. The diagnosis of methemoglobinemia was confirmed based on elevated methemoglobin levels on venous blood gas analysis. Notably, the patient's blood had a chocolate-colored appearance upon admission, which is a characteristic finding in methemoglobinemia. Prompt recognition and management, including the administration of methylene blue, led to the resolution of symptoms. This case highlights the potential complications associated with the consumption of poppers and emphasizes the importance of early intervention.

Methemoglobinemia Secondary to a Traditional Healing Practice Using Mothballs: A Need of Pediatric Vigilance

Acute-onset unexplained hypoxemia persisting despite 100% oxygen has a limited differential diagnosis but poses a challenging diagnostic dilemma. Methemoglobinemia, a hemolytic condition, may lead to significant complications if it goes undiagnosed during the critical golden hour of an emergency department (ED) presentation. This case report presents the clinical details of a 30-month-old child with acute intravascular hemolysis evident by severe pallor and hemoglobinuria and severe hypoxia documented on pulse oximetry. During the ABCDE (Airway, Breathing, Circulation, Disability, Exposure) of the primary survey, "exposure" revealed the parent's deliberate fastening of a mothball around the waist of the baby on the advice of a traditional healer, which was identified as the source of naphthalene toxicity. The swift intervention was undertaken for hypoxic respiratory compromise with 100% oxygen just after triage, and the naphthalene ball with the tied cloth was removed. Arterial blood gas and co-oximetry analysis confirmed the diagnosis of methemoglobinemia, and other laboratory tests suggested severe hemolytic anaemia as well as hemoglobinuria favouring intravascular hemolysis. With the exclusion of other common differentials for hemolytic anaemia, including sickle cell crisis, autoimmune hemolytic anaemia, hemolytic uremic syndrome, and G6PD deficiency, naphthalene exposure was considered the culprit for both hemolysis and methemoglobinemia. After obtaining the history of another similar episode of anaemia six months ago requiring blood transfusion, we retrospected on similar mothball exposure, but parents denied that, saying they were using the mothball only for the last 10 days on the advice of a local healer with intent to get rid of some evil power and sickness in their child. After analyzing the old records of prior hospitalization and getting assured of a normal report of G6PD level, intravenous methylene blue was administered. But in view of an inadequate response, a single blood volume exchange transfusion was performed during the ED stay only, which resulted in a notable reduction in subsequent methemoglobin levels and an improvement of the child's clinical condition by the second day. The child was discharged by the third day with no distress and no further episodes of hemoglobinuria, with detailed parental counselling and follow-up advice. This case underscores the imperative need for timely recognition and effective management of methemoglobinemia in the paediatric population while emphasizing the potential hazards associated with naphthalene exposure. Further comprehensive investigations are warranted to elucidate optimal treatment strategies and explore long-term outcomes in similar clinical scenarios.

Phenazopyridine-Induced Methemoglobinemia in a Jehovah's Witness Treated with High-Dose Ascorbic Acid Due to Methylene Blue Contradictions: A Case Report and Review of the Literature

Methemoglobinemia is an acute medical emergency that requires prompt correction. Physicians should have a high degree of suspicion of methemoglobinemia in cases that present with hypoxemia that does not resolve with supplemental oxygenation, and they should confirm this suspicion with a positive methemoglobin concentration on arterial blood gas. There are multiple medications that can induce methemoglobinemia, such as local anesthetics, antimalarials, and dapsone. Phenazopyridine is an azo dye used over-the-counter as a urinary analgesic for women with urinary tract infections, and it has also been implicated in causing methemoglobinemia. The preferred treatment of methemoglobinemia is methylene blue, but its use is contraindicated for patients with glucose-6-phosphatase deficiency or those who take serotonergic drugs. Alternative treatments include high-dose ascorbic acid, exchange transfusion therapy, and hyperbaric oxygenation. The authors report a case of a 39-year-old female who took phenazopyridine for 2 weeks to treat dysuria from a urinary tract infection and subsequently developed methemoglobinemia. The patient had contraindications for the use of methylene blue and was therefore treated with high-dose ascorbic acid. The authors hope that this interesting case promotes further research into the utilization of high-dose ascorbic acid for managing methemoglobinemia in patients who are unable to receive methylene blue.

Middle ear cholesteatoma resection under general anesthesia in patients with congenital methemoglobinemia: A case report

RATIONALE

Congenital methemoglobinemia is a rare cyanosis cause that can be manifested in affected individuals. We report a case of congenital methemoglobinemia after middle ear cholesteatoma resection under general anesthesia.

PATIENT CONCERNS

The primary concern of the patient is to safely perform cholesteatoma resection of the middle ear to reduce the pain associated with years of surgery and to survive the perioperative period.

DIAGNOSES

Congenital methemoglobinemia type 1.

INTERVENTIONS

The patient underwent general anesthesia and cholesteatoma resection of the middle ear.

OUTCOMES

The patient successfully underwent cholesteatoma resection in the middle ear under general anesthesia and went through the perioperative period smoothly, and successfully returned to society.

LESSONS

For patients requiring general anesthesia complicated with rare methemoglobinemia, we improve the awareness of crisis and make comprehensive preparation and monitoring, learn the pathophysiological mechanism related to the disease, so as to protect the operation of methemoglobin patients under general anesthesia.

Trimethoprim/sulfamethoxazole-induced methemoglobinemia in pediatric patient: A case report

In this report, a case of high dose of sulfamethoxazole/trimethoprim-induced methemoglobinemia and is reported in a young boy with ventilator-associated pneumonia and was treated successfully with methylene blue and cessation of the offending agent.

Intravascular Hemolysis, Methemogolbinemia and Acute Renal Failure in a Young Female

Copper sulfate occurs as large blue crystals in nature, commonly known as "blue vitriol" or "blue stone." It is a potentially lethal poison with significant mortality. Copper sulfate is a powerful oxidizing agent and causes corrosive injury to the mucous membrane. The clinical course involves intravascular hemolysis resulting in anemia, jaundice, and renal failure. Laboratory diagnosis of the condition is not an issue; the difficulty is suspecting it, promptly initiating chelation therapy, and other supportive symptomatic treatment. We present a case of copper sulfate poisoning in a young female with suicidal intent resulting in severe acute toxicity, which was successfully managed by copper chelator (d-Penicillamine) and other supportive measures.

Methemoglobinemia in the Era of COVID-19: A Potential Confounder of Glycemic Control

Glycated hemoglobin A1c (HbA1c) is frequently used as a measure of glycemic control but can be inaccurate in certain clinical scenarios leading to poor estimates of insulin requirements. We present the case of a 76-year-old man with diabetes and COVID infection. HbA1c was measured at 5.7%, though the patient reported home glucose readings of 200 to 300 mg/dL (11.1-16.65 mmol/L). Pulse oximetry on presentation was 50% to 60%, which initially improved to 93% with supplemental oxygen of 15 L via nonrebreather face mask. Treatment with remdesivir and dexamethasone was initiated, but the patient was again found to have low oxygen saturations requiring bilevel positive airway pressure and transfer to the intensive care unit. The patient was started on 1.1 U/kg of insulin daily in a basal-bolus regimen. The patient developed severe hyperglycemia requiring 2.4 U/kg to achieve glycemic control. Co-oximeter analysis of an arterial blood gas sample revealed methemoglobinemia. Exchange transfusion was performed with clinical improvement. Subsequent measurement of fructosamine was 360 umol/L (360 000 µmol/L), correlating with reported home glucose measurements. Methemoglobinemia may impair glycation of hemoglobin or interfere with measurement of HbA1c, thereby compromising the use of this molecule as a marker for glycemic control in patients with this condition.

Co-Occurring Hemolysis and Methemoglobinemia After COVID-19 Infection in Patient With G6PD Deficiency

Hemolytic anemia and methemoglobinemia are known complications in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. They can be elicited by various oxidative stressors. Here we report a case of an adult with the first episode of G6PD deficiency associated hemolysis and methemoglobinemia after acquiring COVID-19 infection, who had no recent exposure to oxidative drugs or fava beans. A 52-year-old gentleman known to have myocardial bridging on aspirin and beta-blocker, with no other medical illnesses, developed anemia symptoms, jaundice, and hypoxia after contracting COVID-19 infection. Further laboratory work revealed non-immune hemolytic anemia, methemoglobinemia, and a positive G6PD screen test. He was treated conservatively with a blood transfusion, and his oxygen saturation improved thereafter. With the widespread COVID-19 infection and its morbidity worldwide, it is crucial to consider methemoglobinemia in the differential diagnosis of hypoxia. Testing for G6PD is an essential next step in such cases, as starting methylene blue in G6PD deficiency can worsen hemolysis. Apart from COVID-19, there is no other identified trigger for the acute event in this patient. It is not known whether COVID-19 infection alone is enough to result in G6PD deficiency-associated hemolysis and methemoglobinemia simultaneously.

Methemoglobinemia Secondary to Inhalation of Automobile Emissions with Suicide Motivations

BACKGROUND

Methemoglobinemia (MetHb) is a rare and potentially severe dyshemoglobinemia that can be induced by exposure to oxidizing agents, decreasing the functional capacity of the hemoglobin molecule to transport and release oxygen into the tissues. MetHb can originate from gases with oxidizing capacity generated by internal combustion engines, although since the universalization of catalyst converters in automobiles, a tiny proportion of MetHb poisoning is due to exposure to engine gases and fumes. Within this group, only two cases due to suicidal motivations have been reported in the last 30 years.

CASE PRESENTATION

Here, we expose the case of a patient with MetHb levels of 25.2% (normal 0-1.5%) who with suicidal motivations had attached and locked a hose to the exhaust pipe of her vehicle with electrical tape, becoming exposed to a sustained concentration of the vehicle's exhaust. Upon her arrival at the emergency department, the presence of generalized greyish cyanosis with alterations of the sensorium, dissociation between saturation measured by arterial blood gas analysis and pulse oximetry (98% vs. 85%), no response to high-flow oxygen therapy, and an excellent response to intravenous methylene blue treatment were highlighted.

CONCLUSIONS

This report illustrates an original case of acute toxic acquired MetHb due to inhalation of oxidizing substances originating from the bad ignition of an internal combustion engine. When evaluating a patient with suspected gas intoxication, we usually consider poisoning by the most common toxins, such as carbon monoxide or cyanide. In this context, we propose an algorithm to assist in the suspicion of this entity in patients with cyanosis in the emergency department. MetHb poisoning should be suspected, and urgent co-oximetry should be requested when there is no congruence between cyanosis intensity and oxygen saturation measured by pulse oximetry, if there is discordance between the results of oxygen saturation measured by arterial blood gas and pulse oximeter, and if there is no response to oxygen treatment. This algorithm could be useful to not delay diagnosis, improve prognosis, and limit potential sequelae.

Case report: Methemoglobinemia caused by nitrobenzene poisoning

Nitrobenzene poisoning is uncommon, with most cases occurring in the dye, paint, and other chemical industries. Nitrobenzene enters the body mainly through the skin, respiratory tract, and oral cavity. Nitrobenzene poisoning symptoms include hypermethemoglobinemia, hemolytic anemia, liver and kidney dysfunction, cardiogenic pulmonary edema, and toxic encephalopathy, which endanger people's lives. Therefore, we present a case of nitrobenzene poisoning caused by skin absorption, focusing on its clinical characteristics and treatment outcomes. A 58 years-old man presented to our department with confusion and cyanosis. He has a history of hypertension and cerebral infarction. The patient was diagnosed with moderate occupational acute benzene poisoning with nitro compounds. Symptomatic support, methylene blue, and other antioxidant treatments were commenced after diagnosis. After treatment, the patient's condition gradually improved, and he was discharged.

The Serious Impact of Comorbidities on Methemoglobinemia: A Case Report

Methemoglobinemia is a rare, life-threatening condition that occurs when the body is exposed to oxidative stress. We present the case of a 72-year-old female with a past medical history of hypertension, obesity, dyslipidemia, and heart failure who was admitted to the emergency department with altered mental status and respiratory failure. After admission, we also identified an atrioventricular block 2:1, anemia, and skin discoloration. We performed endotracheal intubation and started mechanical ventilation due to respiratory failure; however, the patient retained an oxygen "saturation gap" despite adequate ventilation. In the initial laboratory evaluation, methemoglobinemia was found to be 13%, reaching a maximum level of 16%. An electroencephalogram revealed status epilepticus after her admission to the intensive care unit. Despite all efforts and supportive care, methylene blue therapy was never attempted, and the patient died. Our case emphasizes the importance of a high index of suspicion for methemoglobinemia, especially in the presence of an oxygen "saturation gap," and that despite relatively low levels of methemoglobinemia, it can have a more severe clinical presentation in patients with comorbidities. In these patients, a reduced threshold for administering methylene blue should be taken into account.

Dapsone-induced methemoglobinemia and hemolysis in a woman without G6PD deficiency presenting with idiopathic urticaria

BACKGROUND

The appearance of bite cells associated with methemoglobinemia can be caused by oxidizing drugs such as dapsone in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency or high drug serum levels. Bite cells are often pathognomonic for oxidant injury in patients with G6PD deficiency and suggest active hemolysis.

CASE PRESENTATION

We report a case of a woman with no prior history of G6PD deficiency who presented with anemia, methemoglobinemia and bite cells on peripheral blood smear after dapsone therapy for new onset idiopathic urticaria. Laboratory tests for G6PD, blood count and liver function were within normal limits prior to initiation of therapy. During the patient's hospital course, moderate methemoglobinemia and anemia were identified despite mildly increased serum G6PD level. These pathologies were reversed upon stopping dapsone therapy.

CONCLUSION

This case highlights the potential for therapeutic levels of dapsone to induce side effects in patients without G6PD deficiency and highlights the importance of routine blood monitoring for anemia and hemolysis during the course of drug therapy.

Toxin-Induced Methemoglobinemia With Kidney Injury and Hypoxic Brain Injury in a Case of Pesticide Poisoning: A Case Report

In many developing nations like India, the majority of the labor force comprises farmers. Therefore, there is a raised frequency of farmer suicides using pesticides. Toxin-induced methemoglobinemia is otherwise called toxic methemoglobinemia. It is a hematologic disorder attributed to exposure to toxic oxidizing agents and is most commonly seen in cases of poisoning. Methemoglobinemia is a condition in which there is an altered state of hemoglobin, resulting in reduced oxygen delivery to tissues. This case report represents a case of methemoglobinemia with acute kidney injury and hypoxic brain injury seen in a 23-year-old male patient. He was a farmer by occupation and was admitted due to ingestion of a pesticide named HUNT with suicidal intentions. He has had no previous history of psychiatric or neurologic disorders. The patient initially presented with a pulse rate of 110/min and room air saturation of 98% when he was brought to the casualty out patient department (OPD). Unfortunately, it worsened over the next 24 h, after which there was a sudden drop in SpO2 to 78% with oxygen support. Upon further examination and assessment, he was diagnosed with methemoglobinemia, leading to complications such as acute kidney failure and cerebral edema. He was then treated with hemodialysis, methylene blue, and ascorbic acid with viable improvement. This led to his complete recovery after eight days of treatment and support.

A Case Report of Cyanosis With Refractory Hypoxemia: Is It Methemoglobinemia?

Dapsone is used in the treatment of a variety of dermatological conditions and prophylaxis of opportunistic infections. However, if consumed at a dose of more than 200 mg/day, it can cause methemoglobinemia, a condition characterized by elevated methemoglobin levels in the blood; methemoglobin is an abnormal form of hemoglobin, containing iron in the ferric state (Fe^{3 +}) rather than the reduced ferrous form (Fe^{2 +}) found in hemoglobin. A small amount of it is produced in the body due to oxidant damage to the red blood cells. Methemoglobinemia can cause varied clinical manifestations involving the cardio-respiratory and nervous systems depending upon the level of methemoglobin. While it could be congenital, it is commonly caused by exposure to drugs that cause oxidation of hemoglobin, such as benzocaine, dapsone, and nitrates. We report a case of dapsone-induced methemoglobinemia in a previously healthy young female who had consumed 15 tablets of dapsone 100 mg with suicidal intent. She presented with central cyanosis, breathlessness, and altered sensorium after five days of consumption. While the pulse-oximeter showed oxygen saturation (SaO₂) of 84%, arterial blood gas (ABG) analysis showed partial pressure of oxygen (PaO₂) of 427 mmHg and SaO₂ of 98%. This "saturation gap" occurred due to the presence of the abnormal hemoglobin variant. Her cyanosis did not improve despite giving 100% supplemental oxygen. There was no cardiac or respiratory cause to account for her cyanosis. Her methemoglobin level was 45.8%. She was successfully treated with specific antidote methylene blue, mechanical ventilation, and other symptomatic measures. The purpose of this presentation is to help clinicians recognize this condition early, because, if left untreated, it might prove fatal. The diagnostic clues include refractory hypoxemia, central cyanosis in the absence of cardiac and respiratory causes, saturation gap, and chocolate-colored blood.

Toxic Encephalopathy and Methemoglobinemia after 5-Amino-2-(trifluoromethyl)pyridine Poisoning

The aromatic amino compound 5-amino-2-(trifluoromethyl)pyridine acts as an intermediate in the synthesis of pharmaceutical products. However, the toxicity profile of this compound is sparse and no related poisoning events have been reported. Here, we report the case of a 35-year-old man who inhaled 5-amino-2-(trifluoromethyl)pyridine at work. After inhalation, the patient rapidly developed symptoms such as dizziness, fatigue, nausea, vomiting, chest tightness, and loss of consciousness. After admission, methemoglobinemia, hemolytic anemia, acute renal failure, and toxic encephalopathy occurred. Symptoms improved significantly after intravenous treatment with a low dose of methylene blue. This revealed that 5-amino-2-(trifluoromethyl)pyridine is toxic to the human body and can be absorbed through the respiratory tract, resulting in methemoglobinemia and toxic encephalopathy; thus, caution should be taken in industrial production.

A Case of Severe Hypoxia Caused by Phenazopyridine-Induced Methemoglobinemia: A near Fatal Event from Over-the-Counter Medication Use

Methemoglobinemia is a rare blood disorder characterized by the oxidation of heme iron from ferrous (Fe²⁺) to ferric (Fe³⁺) state, which increases oxygen affinity and impairs oxygen release to the tissue causing hypoxia. It can be congenital or acquired; however, most cases are acquired and caused by exogenous substances such as medications, chemicals, and environmental substances. Phenazopyridine is an over-the-counter urinary analgesic medication commonly used for symptomatic relief of dysuria and has been reported to cause methemoglobinemia. However, only a handful of cases of phenazopyridine-induced methemoglobinemia have been reported. We present a case of an 89-year-old female who presented with severe hypoxia, shortness of breath, headache, nausea, and dizziness caused by phenazopyridine-induced methemoglobinemia. She was found to have a methemoglobin level of 21.5% and was treated with methylene blue, leading to a rapid improvement of her symptoms. She was taking one over-the-counter phenazopyridine 200 mg tablet three times daily for two weeks for her chronic dysuria. This case highlights the need to have a high index of suspicion of phenazopyridine-induced methemoglobinemia in a patient presenting with unexplained shortness of breath with a history of phenazopyridine use as it could lead to severe methemoglobinemia with hypoxia that could potentially be fatal if not promptly diagnosed.

Methylene blue: a controversial diagnostic acid and medication?

A narrative review of the literature was conducted to determine if the administration of methylene blue (MB) in humans has potential risks. Studies were identified from MEDLINE, Web of Science, Scopus, and Cochrane. MB is a diagnostic substance used during some diagnostic procedures and also a part of the treatment of several diseases including methemoglobinemia, vasoplegic syndrome, fosfamide-induced encephalopathy, and cyanide intoxication, and the detection of leaks or position of parathyroid corpuscles during surgery. Although the use of MB is historically justified, and it ought to be safe, because it originated as a diagnostic material, the basic toxicological characteristics of this substance are unknown. Despite reports of severe adverse effects of MB, which could significantly exceed any possible benefits evaluated for the given indication. Therefore, the clinical use of MB currently represents a controversial problem given the heterogeneity of available data and the lack of preclinical data. This is in conflict with standards of safe use of such substances in human medicinal practice. The toxic effects of the application of MB are dose-dependent and include serious symptoms such as hemolysis, methemoglobinemia, nausea and vomitus, chest pain, dyspnoea, and hypertension. Some countries regard MB as harmful because of the resulting skin irritation and triggering of an adverse inflammatory response. MB induced serotoninergic toxicity clinically manifests as neuromuscular hyperactivity. This review aims to summarize the current understanding concerning the indications for MB administration and define the potential adverse effects of MB.

Acute dapsone poisoning with methemoglobinemia: a case report

Methemoglobinemia is a common complication of dapsone poisoning. Its´ treatment usually relies on methylene blue infusion. The aim of this study was to report a case of an acute dapsone poisoning with methemoglobinemia treated only with ascorbic acid and activated charcoal. A 16-year-old female voluntary ingested 3 grams of dapsone in an attempt of suicide and presented with desaturation and tachypnea. Lab findings were compatible with methemoglobinemia. After two days of treatment with ascorbic acid and activated charcoal, we observed the disappearance of desaturation and tachypnea. Methemoglobinemia can be treated with ascorbic acid and activated charcoal in limited resource settings.

Reactive nitrogen compounds and their influence on human health: an overview

Nitrogen (N) is a critical component of food security, economy and planetary health. Human production of reactive nitrogen (Nr) via Haber-Bosch process and cultivation-induced biological N₂ fixation (BNF) has doubled global N cycling over the last century. The most important beneficial effect of Nr is augmenting global food supplies due to increased crop yields. However, increased circulation of Nr in the environment is responsible for serious human health effects such as methemoglobinemia ("blue baby syndrome") and eutrophication of coastal and inland waters. Furthermore, ammonia (NH₃) emission mainly from farming and animal husbandary impacts not only human health causing chronic lung disease, inflammation of human airways and irritation of eyes, sinuses and skin but is also involved in the formation of secondary particulate matter (PM) that plays a critical role in environment and human health. Nr also affects human health via global warming, depletion of stratospheric ozone layer resulting in greater intensity of ultra violet B rays (UVB) on the Earth's surface, and creation of ground-level ozone (through reaction of NO₂ with O₂). The consequential indirect human health effects of Nr include the spread of vector-borne pathogens, increased incidence of skin cancer, development of cataracts, and serious respiratory diseases, besides land degradation. Evidently, the strategies to reduce Nr and mitigate adverse environmental and human health impacts include plugging pathways of nitrogen transport and loss through runoff, leaching and emissions of NH₃, nitrogen oxides (NO _x ), and other N compounds; improving fertilizer N use efficiency; reducing regional disparity in access to N fertilizers; enhancing BNF to decrease dependence on chemical fertilizers; replacing animal-based proteins with plant-based proteins; adopting improved methods of livestock raising and manure management; reducing air pollution and secondary PM formation; and subjecting industrial and vehicular NO _x emission to pollution control laws. Strategic implementation of all these presents a major challenge across the fields of agriculture, ecology and public health. Recent observations on the reduction of air pollution in the COVID-19 lockdown period in several world regions provide an insight into the achievability of long-term air quality improvement. In this review, we focus on complex relationships between Nr and human health, highlighting a wide range of beneficial and detrimental effects.

[A Case of Methemoglobinemia Caused by Toluidine Revelation with Dyspnea and Cyanosis]

Toluidine is a known cause of bladder cancer, but it is less widely recognized as a cause of methemoglobinemia because methemoglobinemia is rare. We herein report a case of methemoglobinemia caused by toluidine in a 50-year-old man. A solution of toluidine overflowed from its container during transportation and adhered to the man's clothes, but he drove to his workplace 100 km away without changing his clothes or undergoing decontamination. Before arriving at his workplace, he developed dyspnea and called emergency services, and he was then transported to a local hospital. He had significant cyanosis upon arrival, and arterial blood gas analysis revealed a high methemoglobin level of 44%. He was diagnosed with toluidine-induced methemoglobinemia and was transported to our hospital, where he was admitted to the intensive care unit. Treatment for methemoglobinemia was started immediately after hospitalization, and the patient's symptoms and methemoglobin level improved. Methemoglobinemia should be considered in workers who handle toluidine and develop cyanosis and dyspnea.

Killer hiding under normal oxygen saturation: a case report about methemoglobinemia

BACKGROUND

Inhaled nitric oxide (iNO) is a choice for the treatment of pulmonary hypertension (PH), especially in cases after cardiac surgery. Potential side effects include the formation of higher oxides of nitrogen and methemoglobin (MetHb). Methemoglobinemia is the oxidation of ferrous iron to iron within hemoglobin, impairing its ability to transport oxygen and resulting in tissue hypoxemia. A level of MetHb >10% will induce clinical hypoxia manifestations, and MetHb >70% may be fatal.

CASE DESCRIPTION

Herein we report a rare case of methemoglobinemia due to iNO therapy in a child after cardiac surgery. We found that as MetHb concentrations increased, pulse oximetry overestimated oxygen supplementation without warning clinicians that dangerous hypoxia was developing. Finally, MetHb and oxyhemoglobin (O₂Hb) in arterial blood gas (ABG) provide diagnostic clues. Methylene blue and low dose vitamin C (VC) were used to successfully save the life of the child.

CONCLUSIONS

iNO administration in the intensive care unit should be managed with close monitoring of MetHb levels during treatment. We emphasize the limitations of traditional methods used to assess oxygenation status, especially in the context of methemoglobinemia. In addition, treatment for methemoglobinemia in acute settings should be initiated as soon as possible.

METHEMOGLOBINEMIA - A CASE REPORT AND LITERATURE REVIEW

The objective of this case report is to present a patient with acquired methemoglobinemia due to poisoning of an unknown cause. A 55-year-old man was brought to the Emergency Department, University Hospital Center Zagreb, with an unwell appearance, cyanotic, restless, and presented with a quantitative consciousness disorder. An initial assessment showed decreased oxygen saturation (SpO2 85 [%]), while point-of-care arterial blood gas (ABG) analysis assessed normal partial pressure of oxygen (pO2). Severe lactic acidosis with a compensatory drop in partial pressure of carbon dioxide (pCO2) and high rates of methemoglobin were found. Supportive oxygen therapy and crystalloid solutions were administered, which resulted in rapid clinical recovery within 40 minutes of the initial assessment. Clinical recovery was accompanied by normalized ABG test results taken serially. Typical antidotes, methylene blue and vitamin C, were not administered due to rapid clinical improvement. Methemoglobinemia can be congenital (hereditary) or acquired (toxic). Both conditions are rarely seen in emergency departments, nevertheless, they should be approached properly since methemoglobinemia can be a severe, and fatal, condition. Methemoglobinemia symptoms are the results of inadequate oxygen transport. The diagnosis was confirmed by co-oximetry, while three clinical entities suspected methemoglobinemia: refractory hypoxia, “cyanosis-saturation gap“ and dark brown blood. This paper reports our patient’s clinical presentation, discusses the causes and mechanisms of possible poisoning, and reviews recent guidelines for methemoglobinemia management.

Impact of preemptive rapid testing for glucose-6-phosphate dehydrogenase deficiency prior to rasburicase administration at a tertiary care center: a retrospective study

AIM

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy in humans, can cause acute hemolysis resulting from exposure to certain medications, chemicals, infections and fava beans. Rasburicase, used to manage elevated uric acid levels in the oncologic emergency of tumor lysis syndrome, is one such drug. The Food & Drug Administration (FDA) recommends testing of G6PD status prior to rasburicase administration for patients at higher risk for G6PD deficiency.

METHODS

We performed a retrospective chart review of all oncology patients for whom a semi-quantitative biochemical test for detecting G6PD deficiency was performed prior to rasburicase administration over a 2.5 year period, in a large academic metropolitan hospital.

RESULTS

We identified 16 out of 260 tested individuals as G6PD-deficient (6.1%), including six females. On average, test results were electronically available to health-care providers within 4 hours of sample collection, with most results available within 2-3 hours. Four G6PD-deficient patients developed elevated uric acid levels. Two of the G6PD-deficient patients were treated with rasburicase, and subsequently developed hemolysis, which was appropriately managed.

CONCLUSION

In summary, by providing information about G6PD status with a rapid turnaround time, we have taken a significant step towards personalized medicine in our institution. In spite of the test implementation, two out of four G6PD deficient patients, who were no longer candidates for rasburicase use, still received the drug, highlighting the need for improved provider education.

A Case of Congenital Methemoglobinemia: Rare but Real

Methemoglobin (MetHb) is a form of hemoglobin in which iron in Hb is in an oxidized form (ferric) instead of ferrous, making it difficult to bind with oxygen. Usually, MetHb is present in small quantities (<1%) in humans, but once MetHb increases beyond 3%, the condition is known as methemoglobinemia. It can be further classified into hereditary and acquired. Hereditary forms are a rare cause of hypoxia and cyanosis. Only a few cases have been reported worldwide. Here, we present a case of a 33-year-old female with congenital methemoglobinemia who remains relatively healthy in spite of her underlying condition. This case report focuses on knowledge sharing and practical aspects of managing patients with congenital methemoglobinemia.

Two cases of fatal methemoglobinemia caused by self-poisoning with sodium nitrite: A case report

RATIONALE

Sodium nitrite intoxication reportedly causes severe methemoglobinemia. Recent studies reported that most clinically significant cases resulted from intentional exposure in suicidal attempts. We describe 2 cases of severe methemoglobinemia secondary to intentional sodium nitrite intoxication in suicidal attempts.

PATIENTS CONCERNS

A 26-year-old man and 20-year-old woman attempted suicide by taking sodium nitrite, and were brought to the emergency department.

DIAGNOSIS

The male patient collapsed at the scene. He ingested approximately 18 g of sodium nitrate, and his methemoglobin level was 90.3%. The female patient was conscious, but was cyanotic. She ingested approximately 12.5 g of sodium nitrite, and her methemoglobin level was 54.6%.

INTERVENTIONS

The male patient received advanced cardiac life support in the emergency department. Methylene blue was immediately administered for the female patient.

OUTCOMES

The male patient died despite aggressive resuscitation. The female patient's cyanosis resolved, and her methemoglobin level decreased to 1.2% 3 hours later.

LESSONS

The immediate administration of methylene blue in severe methemoglobinemia patients prevented fatal consequences. The public should be informed about the accessibility and toxicity of sodium nitrite.

Rasburicase induced methemoglobinemia: A systematic review of descriptive studies

PURPOSE

There is an increased number of reports being published on rasburicase-induced methemoglobinemia recently. We aimed to identify and critically evaluate all the descriptive studies that described the rasburicase-induced methemoglobinemia, its treatment approach, and their outcomes.

METHODOLOGY

PubMed, Scopus and grey literature databases were searched from inception to January 2022 using search terms "rasburicase" and "methemoglobinemia" without any language and date restriction. A bibliographic search was also done to find additional studies. Only descriptive studies on Rasburicase-induced methemoglobinemia were included for our review. Two contributors worked independently on study selection, data abstraction, and quality assessment, and any disagreements were resolved by consensus or discussion with a third reviewer.

RESULT

A total of 24 reports including 27 patients (23 male, 3 female patients, and 1 study did not specify the gender of the patient) aged from 5 to 75 years were included in the review. Immediate withdrawal of the drug and administering methylene blue, ascorbic acid, blood transfusion, and supportive oxygen therapy are the cornerstone in the management of rasburicase-induced methemoglobinemia.

CONCLUSION

Rasburicase administration should be followed by careful monitoring of patients for any severe complication and treat it as early as possible appropriately. In a patient who presents with rasburicase-induced haemolysis or methemoglobinemia, it is often important to expect a diagnosis of G6PD deficiency unless otherwise confirmed and to avoid administering methylene blue, even though the patient is from a low-risk ethnicity for G6PDD.

Mothball Ingestion in the Setting of G6PD Deficiency Causing Severe Hemolytic Anemia, Methemoglobinemia, and Multiple Organ Failure in a Toddler

Mothballs containing naphthalene or paradichlorobenzene are known to cause hemolysis and methemoglobinemia. They can also affect the other organs, including the kidneys, liver, lungs, and skeletal muscles. The involvement of 1 or 2 organs at a time has been commonly reported. However, more than 2 organ dysfunction in mothball intoxication is rare and usually indicates severe illness. The intoxication can have more pronounced symptoms in children with glucose-6-phosphate dehydrogenase (G6PD) deficiency. We report this case of a previously healthy 13-month-old patient who presented with severe hemolysis, lactic acidosis, methemoglobinemia, acute renal failure, hepatic dysfunction, and rhabdomyolysis. He required aggressive fluid resuscitation, blood transfusions, and mechanical ventilation. The underlying etiology of his illness was initially unclear; however, upon repeated questioning, the father recalled the patient chewing on a mothball 3-4 days before admission. Hence, mothball intoxication was considered the most plausible clinical diagnosis in this patient. He was given N-acetylcysteine, instead of methylene blue, because of hepatic dysfunction and the fact that G6PD deficiency could not be ruled out in the presence of acute hemolysis. The patient made a full recovery after 2 weeks of intensive care unit management. G6PD testing after 3 months confirmed the deficiency. These mothballs are available in Hawai'i, but this is the first report of such a severe presentation to our knowledge. The presence of methemoglobinemia, severe hemolysis, and thorough history-taking helped us determine the diagnosis of mothball intoxication and enabled definitive treatment.

A Rare Case of Benzocaine-Induced Methemoglobinemia

Methemoglobinemia is a severely dangerous condition that can be induced by congenital mutations or can be acquired. One of the ways to acquire methemoglobinemia is by using topical anesthetics during procedures, such as nasogastric (NG) tube placement, transesophageal echocardiogram (TEE), esophagogastroduodenoscopies (EGD), and during endoscopic retrograde cholangiopancreatography (ERCP).

Herein, we present the case of a 35-year-old lady who presented to the hospital for an initial hysterectomy. However, due to topical anesthetic use during an NG tube placement, she developed methemoglobinemia. She then developed hypoxia, an altered mental status, and had elevated methemoglobinemia levels. She denied any previous episode of methemoglobinemia and had no family history of the condition as well. She was rapidly given methylene blue, which resolved her symptoms and induced normal methemoglobin levels on subsequent arterial blood gas analysis. Those who are unknowingly susceptible to developing methemoglobinemia and receive anesthetics during hospital procedures are at risk for serious adverse effects and clinical deterioration if not treated correctly. Therefore, it is important to recognize the clinical signs of methemoglobinemia as soon as they appear and have the required treatment readily available, as any delay could result in dangerous consequences for the patient. 

Acute hemolysis and methemoglobinemia secondary to fava beans ingestion in a patient with G6PD deficiency: A case report of a rare co-occurrence

RATIONALE

Favism is a well-known cause of acute hemolytic anemia. Rarely, methemoglobinemia can also happen because of fava bean ingestion in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Few cases with this co-occurrence have been reported in the literature.

PATIENT CONCERNS

We report a case of a 47-year-old patient who presented with jaundice that started 2 days after eating fava beans.

DIAGNOSES

Laboratory investigations revealed anemia with evidence of hemolysis (high reticulocytes count, high indirect bilirubin, bite cells in peripheral smear). Blood gases showed high methemoglobin level. Reduced level of G6PD enzyme confirmed the diagnosis of G6PD deficiency.

INTERVENTION

The patient was kept on supplemental oxygen. He was counselled to avoid food and drugs that can cause acute hemolysis.

OUTCOMES

Oxygen saturation improved gradually. The patient was discharged without any complications after 2 days.

LESSONS

Patients with G6PD deficiency can develop both acute hemolytic anemia and methemoglobinemia secondary to fava beans ingestion. These patients should not receive methylene blue to avoid worsening hemolysis.

Methylene Blue Infusion to Treat Severe Dapsone-Induced Methemoglobinemia in a Pediatric Patient

Dapsone overdose is a well-known potent cause of methemoglobinemia and hemolytic anemia. We discuss a case of a two-year-old male who developed severe persistent methemoglobinemia treated with multiple doses of methylene blue (MB), multidose activated charcoal, and vitamin C. Methylene blue infusion (rather than bolus dosing) aided in controlling this patient's methemoglobin (MetHb) levels and symptoms and may reduce the total needed dose.

A Case Report of Acute Transient Encephalopathy Following a Trans-esophageal Echocardiography

Methemoglobinemia is caused due to an increase in methemoglobin in the blood, impairing oxygen transfer to tissues. Acquired methemoglobinemia is caused by various drugs like local anesthetics, antibiotics, nitrates, nitrites, and food additives. We present a case of a 73-year-old male who presented with cyanosis, altered mental status, and hypoxia following transesophageal echocardiography. Arterial blood gas analysis revealed methemoglobinemia. He had been given topical lidocaine and benzocaine spray before the procedure. He improved after the administration of methylene blue. The case highlights the importance of considering methemoglobinemia in patients presenting with cyanosis, altered mental status, and hypoxia after endoscopic procedures.

Suspected Drinking Water Poisoning in a Domestic Kitten with Methemoglobinemia

A 4-month-old male indoor cat was referred for dyspnea, mental dullness and weakness, which appeared two days earlier. The cat had been adopted at 3 months of age. Physical exam showed cyanosis, dyspnea and mild hypothermia. The “spot test” was supportive of methemoglobinemia. Co-oximetry blood gas analysis revealed severe methemoglobinemia (81.40%), severe hyperchloremia and mild hyponatremia. CBC, biochemistry and urinalysis were within normal limits, blood smear showed the presence of Heinz bodies. Treatment was instituted with oxygen therapy, methylene blue 1% solution, ascorbic acid, intravenous fluid therapy. The clinical course was favorable with rapid improvement of cyanosis and methemoglobinemia (4.2%). Acquired methemoglobinemia was hypothesized. Two weeks after discharge the cat was asymptomatic but mild methemoglobinemia (15.60%) and hyperchloremia were evident. Exposure to oxidants contained in drinking water was suspected so the owners were instructed to use bottled water only. One month later the cat was asymptomatic, and methemoglobinemia and chloremia were within normal limits. Even if a congenital form due to cytochrome b5 reductase deficiency cannot be ruled out, drinking water intoxication is the most likely cause of methemoglobinemia in this cat.

Review of potential risks associated with supplemental dietary exposure to nitrate-containing compounds in swine-a paradox in light of emerging benefits

Calcium nitrate has been reported to benefit reproductive outcomes in sows and their offspring when administered via the feed (15 to 19 mg/kg-body weight [bw]/day) during the periparturient period. Traditionally, dietary nitrate had been considered a methemoglobinemia (MetHb) risk in swine. Similar hazard concerns have existed in humans, but a recent benefit/risk analysis established that nitrate levels associated with well-recognized health benefits outweigh potential risks. A similar benefit/risk perspective in swine was lacking and challenged by sparse published hazard data, often referenced within larger reviews related to all livestock. The objective of this review was to better characterize the potential for adverse health and performance effects reported in the literature for swine consuming nitrate and to provide metrics for evaluating the reliability of the studies reviewed. Supplemental exposure via feed or drinking water was considered for any life stage, dose, and exposure duration. More than 30 relevant studies, including case reports and reviews, examined calcium, potassium, sodium, or unspecified nitrate salts at doses up to 1,800 mg nitrate/kg-bw/day for exposures ranging from 1 to 105 d. The studies primarily evaluated weight gain, blood methemoglobin levels, or vitamin A homeostasis in sows or growing swine. An extensive review of the literature showed reports of adverse effects at low nitrate doses to be of low reliability. Conversely, reliable studies corroborate nitrate intake from feed or drinking water at levels equal to or greater than the European Food Safety Authority's no-observed-adverse-effect level (NOAEL) for swine of 410 mg nitrate/kg-bw/day, with no MetHb or other adverse effects on reproduction, growth, or vitamin A levels. Using a weight-of-evidence evaluation, we have moderate-to-high confidence that the NOAEL for nitrate supplementation in swine is likely between 600 and 800 mg/kg-bw/day. These levels are several-fold higher than dietary nitrate concentrations (19 mg/kg-bw/day) that are known to benefit birth outcomes in sows. This review elucidates the quality and reliability of the information sources historically used to characterize nitrate in swine feed as a contaminant of concern. Results from this evaluation can assist risk managers (e.g., regulatory officials and veterinarians) in consideration of proposed benefits as well as reassuring swine producers that low-level nitrate supplementation is not anticipated to be a concern.

A retrospective analysis of 122 immune thrombocytopenia patients treated with dapsone: Efficacy, safety and factors associated with treatment response

BACKGROUND

The optimum second-line treatment or best sequence of treatments for immune thrombocytopenia (ITP) are yet to be determined. Our institution has accumulated extensive experience regarding the use of dapsone as second-line therapy for ITP.

OBJECTIVES

We aimed to assess the efficacy rate and safety of dapsone treatment in ITP patients.

PATIENTS/METHODS

Here we report our experience in a retrospective study, including 122 patients, with a median treatment duration with dapsone of 6 months and a median follow-up period of 3.4 years.

RESULTS

The overall response rate in this cohort was 66%, including 24% of complete responses. Among responders, in 24% a relapse occurred while on treatment. Therefore, a sustained response was observed in 51% of patients. Interestingly, 81% of the responders maintained the response after the interruption of treatment, for a median time of 26 months. Side effects were reported in 16% of the patients in this cohort and treatment was interrupted due to side effects in 11% of patients. The main cause in these cases was hemolytic anemia and methemoglobinemia. Reductions in hemoglobin levels during the use of dapsone were seen in 94% of the patients. Responders presented significantly greater reductions in their hemoglobin levels than nonresponders did: median hemoglobin drop of 1.9 g/dl vs. 1.2 g/dl (p = .004).

CONCLUSIONS

Our findings suggest that dapsone has adequate efficacy and is well tolerated. Although the mechanism of action is still unclear, our observation that the degree in the drop of hemoglobin is greater in responders suggest a possible role of the blockage of the reticuloendothelial system in the therapeutic effect of the drug.

Congenital Methemoglobinemia and Unstable Hemoglobin Variant in a Child With Cyanosis

Methemoglobinemia (Meth) is a rare hemoglobin (Hb) disorder with distinguished clinical features and complex pathophysiology. We present a three-year-old female who was diagnosed with congenital methemoglobinemia when she presented with peri-oral cyanosis and profound oxygen desaturation in the 20-30% range. This patient also had elevated deoxyhemoglobin (HHb) not explained by methemoglobinemia alone; the low pulse oximetry (SpO₂) reading suggested a rightward-shift oxyhemoglobin (O₂Hb) dissociation curve, which is the opposite of that expected in methemoglobinemia. This, along with evidence of hemolysis, raised the possibility of a concomitant low-oxygen affinity hemoglobinopathy, which could explain elevated HHb. Hemoglobin electrophoresis identified an abnormal hemoglobin variant which was categorized as heterozygous for unstable beta globin variant. The patient responded well to one dose of methylene blue, vitamin C, supportive oxygen (O₂) therapy, and IV hydration and was discharged with a baseline of 50-60% SpO₂ on room air. We are reporting this case along with a brief review of the medical literature.

Amyl Nitrite-Induced Hemolytic Anemia: Acute Therapy and Prevention

Inhaled nitrites have been a substance of recreational use for centuries, primarily among men who have sex with men (MSM). However, there is a lack of awareness of the use of inhaled nitrites in this population and the possible complications and health disparities it carries. In this case report, we present a 62-year-old man with a past medical history of glucose-6 phosphate dehydrogenase (G6PD) deficiency presenting with severe hemolytic anemia and methemoglobinemia after recreational use of inhaled nitrites. The case was complicated with the presence of methemoglobinemia in a patient with G6PD deficiency. This report also aims to increase awareness of the use of nitrites in the MSM population. The use of nitrites is a predictor for high-risk sexual behavior and is associated with positive human immunodeficiency virus (HIV) status.