Therapeutic effect of ascorbic acid on dapsone-induced methemoglobinemia in rats

Ascorbic Acid for Methemoglobinemia Treatment: A Case Report and Literature Review

Purpose: Ascorbic acid has been proposed as an alternative treatment for methemoglobinemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. However, its efficacy has never been compared to that of methylene blue given the inability of patients with G6PD deficiency to receive methylene blue. We present a case of methemoglobinemia treated with ascorbic acid in a patient without G6PD deficiency who had previously received methylene blue. Summary: A 66-year-old male was treated for methemoglobinemia deemed to be secondary to benzocaine throat spray. He received intravenous (IV) methylene blue but had a severe reaction: diaphoresis, lightheadedness, and hypotension. The infusion was stopped prior to completion. Approximately 6 days later he presented with methemoglobinemia following an additional overconsumption of benzocaine and was treated with ascorbic acid. In both instances his methemoglobin levels were >30% on arterial blood gas on admission and decreased to 6.5% and 7.8%, respectively, after administration of methylene blue and ascorbic acid. Conclusion: Ascorbic acid had a similar effect on decreasing the concentration of methemoglobin compared to methylene blue. Further research into use of ascorbic acid as a recommended agent for treatment of methemoglobinemia is warranted.

The Potential Effect of Dapsone on the Inflammatory Reactions in COVID-19: Staggering View

Severe SARS-CoV-2 infection is linked with an overstated immune response with the succeeding release of pro-inflammatory cytokines and progression of the cytokine storm. In addition, severe SARS-CoV-2 infection is associated with the development of oxidative stress and coagulopathy. Dapsone (DPS) is a bacteriostatic antibiotic that has a potent anti-inflammatory effect. Thus, this mini-review aimed to elucidate the potential role of DPS in mitigating inflammatory disorders in COVID-19 patients. DPS inhibits neutrophil myeloperoxidase, inflammation, and neutrophil chemotaxis. Therefore, DPS could be effective against neutrophilia-induced complications in COVID-19. In addition, DPS could be effective in mitigating inflammatory and oxidative stress disorders by suppressing the expression of inflammatory signaling pathways and the generation of reactive oxygen species (ROS) correspondingly. In conclusion, DPS might be effective in the management of COVID-19 through the attenuation of inflammatory disorders. Therefore, preclinical and clinical studies are reasonable in this regard.

Hemolytic anemia in COVID-19

COVID-19 is a global pandemic triggered by the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 entry point involves the interaction with angiotensin-converting enzyme 2 (ACE2) receptor, CD147, and erythrocyte Band3 protein. Hemolytic anemia has been linked to COVID-19 through induction of autoimmune hemolytic anemia (AIHA) caused by the formation of autoantibodies (auto-Abs) or directly through CD147 or erythrocyte Band3 protein-mediated erythrocyte injury. Here, we aim to provide a comprehensive view of the potential mechanisms contributing to hemolytic anemia during the SARS-CoV-2 infection. Taken together, data discussed here highlight that SARS-CoV-2 infection may lead to hemolytic anemia directly through cytopathic injury or indirectly through induction of auto-Abs. Thus, as SARS-CoV-2-induced hemolytic anemia is increasingly associated with COVID-19, early detection and management of this condition may prevent the poor prognostic outcomes in COVID-19 patients. Moreover, since hemolytic exacerbations may occur upon medicines for COVID-19 treatment and anti-SARS-CoV-2 vaccination, continued monitoring for complications is also required. Given that, intelligent nanosystems offer tools for broad-spectrum testing and early diagnosis of the infection, even at point-of-care sites.

Methaemoglobinaemia in pregnancy: Real world experience in a single centre in Malaysia

The literature on methaemoglobinaemia in pregnancy is scarce, imposing clinical challenges to both obstetricians and haematologists. We report a total of nine pregnancies with methaemoglobinaemia treated in our centre. Their methaemoglobin levels, mode of delivery, pregnancy management and outcome were summarized.

Challenges in Managing a Lepromatous Leprosy Patient Complicated with Melioidosis Infection, Dapsone-Induced Methemoglobinemia, Hemolytic Anemia, and Lepra Reaction

Patient: Female, 22-year-old

Final Diagnosis: Lepromatous leprosy co-infected with melioidosis • complicated by dapsone-induced methaemoglobinaemia and type 2 lepra reaction

Symptoms: Cyanosis • fever • jaundice • pallor • skin rash

Medication: —

Clinical Procedure: —

Specialty: Dermatology • Hematology • Infectious Diseases • General and Internal Medicine • Microbiology and Virology

Methemoglobinemia: Infants at risk

Methemoglobin is formed when the iron center in hemoglobin is oxidized from ferrous iron to ferric iron. The functional consequence of this change is that hemoglobin is transformed to methemoglobin and cannot oxygenate tissues adequately, causing hypoxia and cyanosis. Infants have unique physiology that increases their risk of developing methemoglobinemia. Infants drink more water per body weight compared to children and adults, have lower NADH cyb5r reductase activity that converts methemoglobin to hemoglobin, and have a higher percentage of fetal hemoglobin, which is easier to convert to methemoglobin. A well-studied exposure to a chemical that can cause methemoglobinemia in infants is nitrate in well water. For the first part specifically about methemoglobin in infants, articles that were recent (2015-now) were given preference over articles that were older. Search terms included: methemoglobin, methemoglobinemia, infant, acquired, congenital, and methylene blue. For the latter half of the paper on nitrate and methemoglobinemia, preference was given to articles that described regionally important cases. In addition, search terms were: Minnesota, methemoglobinemia, nitrate, well water, drinking water, and infant. Acquired methemoglobinemia is rare, yet can still be seen in medical settings, and when an infant is exposed to nitrate in well water above 10 mg/L. To prevent exposure, parents should have their water tested for nitrate before the baby comes home. Physicians should make it practice to ask what the source of drinking water is for newly pregnant women and urge them to test for nitrate and bacteria if using a well. Using bottled water to make formula is also an option, but the best option is still breastfeeding.