Unexplained Methemoglobinemia in Coronavirus Disease 2019: A Case Report

Thambiah S, Masiman AD, Samsudin IN, Lai YY. Refractory hypoxia and saturation gap in a COVID-19 patient

Acquired methemoglobinemia, predominantly due to oxidizing medications occurs when heme iron in hemoglobin is oxidized from ferrous to ferric ion and binds oxygen irreversibly leading to functional anemia, cyanosis, and tissue hypoxia. We report a case of a 60-year-old man with multiple comorbidities who was diagnosed with coronavirus disease 2019 (COVID-19) and developed methemoglobinemia after consumption of prescribed supplements. He presented with dyspnea and cyanosis. An oxygen saturation gap with characteristic chocolate-brown arterial blood indicated methemoglobinemia. Outsourced methemoglobin (MetHb) was increased at 9.0%. Despite aggressive intervention, he succumbed to his illness. In this case, we discuss the pathophysiology of why some individuals, especially the elderly with COVID-19 are more susceptible to develop methemoglobinemia after possibly being exposed to oxidizing agents. Laboratory methods for assessing oxygen saturation, including pulse oximetry, arterial blood gas and co-oximetry are examined in relation to this case. The importance of considering a diagnosis of methemoglobinemia based on clinical and biochemical findings although MetHb assay or co-oximetry are not readily available is also emphasized.

Application of methylene blue for the prevention and treatment of COVID-19: A narrative review

The newest virus from the SARS family of viruses called acute syndrome-coronavirus-2 (SARS-CoV-2), which causes COVID-19 disease, was identified in China at the end of 2019. In March 2020, after it spread to 29 additional countries, it was declared a pandemic by the World Health Organization (WHO). SARS-CoV-2 infection mainly starts through the respiratory tract and causes a wide spectrum of symptoms from asymptomatic infections to acute respiratory distress syndrome with multi-organ failure and vasoplegic shock. Among the many immunomodulatory and antiviral drugs that have been studied for the treatment of COVID-19, methylene blue (MB) may play an influential role. This article reviews the history of MB applications, the antiviral effects of MB against SARS-CoV-2, and the results of in vivo and in vitro studies of the use of MB in COVID-19. Based on studies, MB can simultaneously affect most of the host's harmful responses caused by SARS-CoV-2 infection due to its multiple properties, including anti-hypoxemia, anti-oxidant, immune system modulator, and antiviral. The use of MB is associated with a reduction in the possibility of getting infection, and mortality, and can be used as a safe, effective, cheap, and available treatment option with minimal side effects for the clinical management of COVID-19.

Dapsone-Induced Methemoglobinemia Presenting Concomitantly With COVID-19 Pneumonia and Pulmonary Embolism: A Case Report

Acquired methemoglobinemia is a treatable condition that is often clinically subtle and can be missed on routine clinical assessment. We present a 73-year-old male who was evaluated in the emergency department with worsening respiratory symptoms requiring oxygen. He tested COVID-19 positive and had new pulmonary emboli evident on his CT chest. The patient was on dapsone therapy as a treatment for bullous pemphigoid. The discrepancy between his oxygen levels on the pulse oximeter and blood gas was noted and was treated with 3% methylene blue for dapsone-induced methemoglobinemia. The patient received treatment for COVID-19 pneumonia and pulmonary emboli. Our case demonstrates that dapsone-induced methemoglobinemia can present concomitantly with other more common causes of acute hypoxic respiratory failure. It is noteworthy for physicians to maintain a high index of suspicion for oxygen level discrepancy in hypoxic patients and consider the possibility of acquired methemoglobinemia. Hence, earlier detection and treatment of the etiology of tissue hypoxia.

Hydroxytyrosol and Arginine as Antioxidant, Anti-Inflammatory and Immunostimulant Dietary Supplements for COVID-19 and Long COVID

Phytochemicals from plant extracts are becoming increasingly popular in the world of food science and technology because they have positive effects on human health. In particular, several bioactive foods and dietary supplements are being investigated as potential treatments for chronic COVID. Hydroxytyrosol (HXT) is a natural antioxidant, found in olive oil, with antioxidant anti-inflammatory properties that has been consumed by humans for centuries without reported adverse effects. Its use was approved by the European Food Safety Authority as a protective agent for the cardiovascular system. Similarly, arginine is a natural amino acid with anti-inflammatory properties that can modulate the activity of immune cells, reducing the production of pro-inflammatory cytokines such as IL-6 and TNF-α. The properties of both substances may be particularly beneficial in the context of COVID-19 and long COVID, which are characterised by inflammation and oxidative stress. While l-arginine promotes the formation of ^•NO, HXT prevents oxidative stress and inflammation in infected cells. This combination could prevent the formation of harmful peroxynitrite, a potent pro-inflammatory substance implicated in pneumonia and COVID-19-associated organ dysfunction, as well as reduce inflammation, improve immune function, protect against free radical damage and prevent blood vessel injury. Further research is needed to fully understand the potential benefits of HXT and arginine in the context of COVID-19.

Glycated hemoglobin level dynamics in COVID-19 survivors: 12 months follow-up study after discharge from hospital

INTRODUCTION

One of the stages of reproduction of SARS-CoV-2 is the S-protein glycosylation to facilitate penetration into target cells. It has been suggested that SARS-CoV-2 is able to enter erythrocytes, interact with heme and porphyrin, which could influence HbA1c levels. Assessment of HbA1c levels in individuals with acute COVID-19 and after recovery may show clinical relevance of this hypothesis.

AIM

To assess HbA1c levels in patients with COVID-19 in the acute phase and in early (6-8 weeks) and late (52±2 weeks) periods after recovery.

MATERIALS AND METHODS

We conducted a multicenter prospective study, which included patients hospitalized in Endocrinology Research Centre and the City Clinical Hospital № 52" diagnosed with COVID-19, virus identified/ not identified. Patients were divided into three groups according to baseline HbA1c level and the presence or absence of previous history of diabetes previous history of diabetes mellitus (DM): HbA1c ≤ 6.0%, HbA1c > 6.0% and patients with DM. Patients were examined during the acute COVID-19 phase and in early (6-8 weeks) and late (52±2 weeks) periods after recovery. Oral glucose tolerance test was performed in the group with initial HbA1c > 6.0% to clarify the diagnosis.

RESULTS

We included 194 patients in the study. During the follow-up, 52 patients were examined in 6-8 week period: 7 with HbA1c ≤ 6.0%, 34 with HbA1c > 6.0%, 11-with previously diagnosed DM. Carbohydrate metabolism assessment in the later stages (52±2 weeks) after recovery was performed in 78 patients: 33 patients with HbA1c ≤ 6.0%, 36 patients with HbA1c > 6.0% and 9 patients with previously established diabetes. HbA1c median in patients with HbA1c ≤ 6.0% was 5.7% [5.3;5.8], with HbA1c>6.0% -6.4% [6.2; 6.6], with previously diagnosed DM-7.7% [7.2; 8.9]. Statistically significant decrease in HbA1c over time 6-8 weeks after extracts were obtained in both groups of individuals without a history of DM (Wilcoxon test, p<0.05). After 52±2 weeks we observed HbA1c decrease in all three groups (Fridman test, p<0.05): in patients with HbA1c ≤ 6.0% median HbA1c was 5.5[5.3;5.7], with HbA1c>6.0% - 6.1[6.15;6.54], with previously diagnosed DM-7.8 [5.83; 8.08]. Development of DM after 52±2 weeks was recorded in 7.24% of all examined patients without a history of DM, which is 16.6% of the total number of patients examined in dynamics with HbA1c > 6.0%.

CONCLUSION

HbA1c elevation during the acute phase of COVID-19 may be false due to the effect of SARS-CoV-2 on hemoglobin kinetics and/or detection on the surface of the SARS-CoV-2 virion highly glycosylated S-proteins by high performance liquid chromatography determinations. Upon detection HbA1c > 6.0% in patients with COVID-19 in the active phase of the disease without concomitant hyperglycemia re-determine the level of HbA1c after recovery is recommended.

SARS-CoV-2 infection, pulse oximetry, and interpretive caveats

Hypoxaemia in COVID-19 does not necessarily imply COVID pneumonia or post-COVID lung fibrosis, and the caveats of finger pulse oximetry should be remembered. Drug-induced methaemoglobinemia should be considered in individuals with unexplained cyanosis, refractory hypoxaemia, or the presence of a saturation gap. Here, we share our recent encounter of ‘spurious hypoxia’ in a patient with COVID-19 and methaemoglobinemia.

Coexistence of carbon monoxide intoxication and COVID-19

Introduction This case report aimed to report two patients admitted to the emergency department with a preliminary diagnosis of carbon monoxide intoxication and was diagnosed with COVID-19 during their follow-up. Case 1 A 73-year-old female patient presented with weakness and shortness of breath complaints to the emergency department. Carboxyhemoglobin (COhgb) reached 36.2 %. Atypical pneumonic infiltration with peripheral and central patchy consolidations in the zones in hemothorax images from computerized tomography. The patient was tested positive for COVID-19 after a PCR test. The COhgb values of the patient reached 16 % after 3 h. Then, it dropped to 3.0 % after 8 h. Case 2 A 77-year-old male patient presented with shortness of breath and nausea complaints to the emergency department. COhgb (carboxyhemoglobin) reached 30%. Emphysematous changes in the lung parenchyma and increased peribronchial densities in the lobes were shown in computed tomography. The patient was tested positive for COVID-19 after a PCR test. The COhgb values of the patient reached 13 after 3 h. It dropped to 2.4 after 8 h. Conclusion Carbon monoxide intoxication is a significant public health problem with a high probability of death. Detailed studies and meta-analyses are needed to affect the prognosis of COVID-19 disease.

Carboxyhemoglobinemia in Critically Ill Coronavirus Disease 2019 Patients

Carboxyhemoglobinemia is a common but a serious disorder, defined as an increase in carboxyhemoglobin level. Unfortunately, there are few data on carboxyhemoglobinemia in coronavirus disease 2019 (COVID-19) patients. Therefore, our study aimed to evaluate the incidence and etiologies of carboxyhemoglobinemia in COVID-19 patients and determine any association between carboxyhemoglobinemia and novel coronavirus infection. A retrospective chart review was performed at an academic medical center for all inpatient COVID-19 cases with either single or serial carboxyhemoglobin (COHb) levels from March 2020 through August 2020.Our study demonstrates that carboxyhemoglobinemia in COVID-19 patients is due to sepsis, hemolysis, and cytokine storm, triggered by the novel coronavirus infection sequela and is not directly from the virulence of novel coronavirus. Given the coexisting illnesses in critically ill COVID-19 patients, it is impossible to establish if coronavirus virulence was the culprit of elevated COHb levels. Moreover, our study found a high incidence of carboxyhemoglobinemia in critically ill COVID-19 patients. The oxygen saturation measured by pulse oximetry can be inaccurate and unreliable; however, our study could not demonstrate any uniform results on the discrepancy between oxygen saturation measured by pulse oximetry and arterial blood gas. In this study, COHb levels were measured using a CO-oximeter. Therefore, we recommend monitoring the COHb level routinely in critically ill COVID-19 patients to allow more effective and prompt treatment.

Rapid Identification of Druggable Targets and the Power of the PHENotype SIMulator for Effective Drug Repurposing in COVID-19

The current, rapidly diversifying pandemic has accelerated the need for efficient and effective identification of potential drug candidates for COVID-19. Knowledge on host-immune response to SARS-CoV-2 infection, however, remains limited with very few drugs approved to date. Viable strategies and tools are rapidly arising to address this, especially with repurposing of existing drugs offering significant promise. Here we introduce a systems biology tool, the PHENotype SIMulator, which - by leveraging available transcriptomic and proteomic databases - allows modeling of SARS-CoV-2 infection in host cells in silico to i) determine with high sensitivity and specificity (both > 96%) the viral effects on cellular host-immune response, resulting in a specific cellular SARS-CoV-2 signature and ii) utilize this specific signature to narrow down promising repurposable therapeutic strategies. Powered by this tool, coupled with domain expertise, we have identified several potential COVID-19 drugs including methylprednisolone and metformin, and further discern key cellular SARS-CoV-2-affected pathways as potential new druggable targets in COVID-19 pathogenesis.

The Role of Methemoglobin and Carboxyhemoglobin in COVID-19: A Review

Following the outbreak of a novel coronavirus (SARS-CoV-2) associated with pneumonia in China (Corona Virus Disease 2019, COVID-19) at the end of 2019, the world is currently facing a global pandemic of infections with SARS-CoV-2 and cases of COVID-19. Since severely ill patients often show elevated methemoglobin (MetHb) and carboxyhemoglobin (COHb) concentrations in their blood as a marker of disease severity, we aimed to summarize the currently available published study results (case reports and cross-sectional studies) on MetHb and COHb concentrations in the blood of COVID-19 patients. To this end, a systematic literature research was performed. For the case of MetHb, seven publications were identified (five case reports and two cross-sectional studies), and for the case of COHb, three studies were found (two cross-sectional studies and one case report). The findings reported in the publications show that an increase in MetHb and COHb can happen in COVID-19 patients, especially in critically ill ones, and that MetHb and COHb can increase to dangerously high levels during the course of the disease in some patients. The medications given to the patient and the patient’s glucose-6-phospate dehydrogenase (G6PD) status seem to be important factors determining the severity of the methemoglobinemia and carboxyhemoglobinemia. Therefore, G6PD status should be determined before medications such as hydroxychloroquine are administered. In conclusion, MetHb and COHb can be elevated in COVID-19 patients and should be checked routinely in order to provide adequate medical treatment as well as to avoid misinterpretation of fingertip pulse oximetry readings, which can be inaccurate and unreliable in case of elevated MetHb and COHb levels in the blood.