Methemoglobinemia and hemolytic anemia after COVID-19 infection without identifiable eliciting drug: A case-report

Hemoglobin and Its Relationship with Fatigue in Long-COVID Patients Three to Six Months after SARS-CoV-2 Infection

Background: While some long-term effects of COVID-19 are respiratory in nature, a non-respiratory effect gaining attention has been a decline in hemoglobin, potentially mediated by inflammatory processes. In this study, we examined the correlations between hemoglobin levels and inflammatory biomarkers and evaluated the association between hemoglobin and fatigue in a cohort of Long-COVID patients. Methods: This prospective cohort study in the Netherlands evaluated 95 (mostly hospitalized) patients, aged 40-65 years, 3-6 months post SARS-CoV-2 infection, examining their venous hemoglobin concentration, anemia (hemoglobin < 7.5 mmol/L in women and <8.5 mmol/L in men), inflammatory blood biomarkers, average FSS (Fatigue Severity Score), demographics, and clinical features. Follow-up hemoglobin was compared against hemoglobin during acute infection. Spearman correlation was used for assessing the relationship between hemoglobin concentrations and inflammatory biomarkers, and the association between hemoglobin and fatigue was examined using logistic regression. Results: In total, 11 (16.4%) participants were suffering from anemia 3-6 months after SARS-CoV-2 infection. The mean hemoglobin value increased by 0.3 mmol/L 3-6 months after infection compared to the hemoglobin during the acute phase (p-value = 0.003). Whilst logistic regression showed that a 1 mmol/L greater increase in hemoglobin is related to a decrease in experiencing fatigue in Long-COVID patients (adjusted OR 0.38 [95%CI 0.13-1.09]), we observed no correlations between hemoglobin and any of the inflammatory biomarkers examined. Conclusion: Our results indicate that hemoglobin impairment might play a role in developing Long-COVID fatigue. Further investigation is necessary to identify the precise mechanism causing hemoglobin alteration in these patients.

Erythrocytes Functionality in SARS-CoV-2 Infection: Potential Link with Alzheimer's Disease

Coronavirus disease 2019 (COVID-19) is a rapidly spreading acute respiratory infection caused by SARS-CoV-2. The pathogenesis of the disease remains unclear. Recently, several hypotheses have emerged to explain the mechanism of interaction between SARS-CoV-2 and erythrocytes, and its negative effect on the oxygen-transport function that depends on erythrocyte metabolism, which is responsible for hemoglobin-oxygen affinity (Hb-O2 affinity). In clinical settings, the modulators of the Hb-O2 affinity are not currently measured to assess tissue oxygenation, thereby providing inadequate evaluation of erythrocyte dysfunction in the integrated oxygen-transport system. To discover more about hypoxemia/hypoxia in COVID-19 patients, this review highlights the need for further investigation of the relationship between biochemical aberrations in erythrocytes and oxygen-transport efficiency. Furthermore, patients with severe COVID-19 experience symptoms similar to Alzheimer's, suggesting that their brains have been altered in ways that increase the likelihood of Alzheimer's. Mindful of the partly assessed role of structural, metabolic abnormalities that underlie erythrocyte dysfunction in the pathophysiology of Alzheimer's disease (AD), we further summarize the available data showing that COVID-19 neurocognitive impairments most probably share similar patterns with known mechanisms of brain dysfunctions in AD. Identification of parameters responsible for erythrocyte function that vary under SARS-CoV-2 may contribute to the search for additional components of progressive and irreversible failure in the integrated oxygen-transport system leading to tissue hypoperfusion. This is particularly relevant for the older generation who experience age-related disorders of erythrocyte metabolism and are prone to AD, and provide an opportunity for new personalized therapies to control this deadly infection.

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 due to Hemolysis Secondary to Infection in a Child: A Case Report

Methemoglobinemia is a rare condition characterised by hypoxic state manifesting as headache, nausea, fatigue, and confusion. We report a 2-year-old boy presenting with fever and cough for 7 days with an episode of hypoxia as the saturation declined and did not improve on face mask oxygenation. On further evaluation, acute intravascular hemolysis was established following decreased haemoglobin level, increased levels of lactate dehydrogenase, and unconjugated bilirubin in the setting of documented infection. Assessment of arterial blood gas showed a significantly raised saturation gap and detection of methemoglobin confirmed the diagnosis. He was managed conservatively with packed red blood cells transfusion following which hypoxia was corrected. Methemoglobinemia as a result of hemolysis can be a non-cardio-respiratory cause of hypoxia and inciting aetiology needs to be addressed.

Keywords

case reports; hemolysis; hypoxia; infection; methemoglobinemia.

Methemoglobinemia and acute hemolysis induced by high intravenous doses of vitamin C in a COVID-19 patient with unrecognized glucose-6- phosphate-dehydrogenase deficiency

In glucose-6-phosphate-dehydrogenase deficiency (favism), exposure to oxidant agents can trigger hemolytic crises. The intravenous administration of very high doses of vitamin C was proposed as a treatment for severe coronavirus disease 2019 (COVID-19) pneumonia. Unlike low vitamin C doses, very high doses (>6 gr daily) can promote H2O2 formation, oxidation of hemoglobin to methemoglobin and, eventually, hemolytic anemia in patients with favism. We here describe the case of a 77-year old man hospitalized for severe COVID-19 pneumonia and treated with a mean daily dose of 9.5 gr of intravenous vitamin C during the first 6 days. He developed methemoglobinemia and hemolytic anemia, which improved after interruption of vitamin C treatment. Previously unrecognized glucose- 6-phophate-dehydrogenase deficiency was diagnosed. This first case of vitamin Cinduced hemolytic anemia in a COVID-19 patient indicates the need of a screening for glucose-6-phosphate-dehydrogenase deficiency before treatment with very high vitamin C doses or for long period.

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.

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.

Methemoglobin formation in mutant hemoglobin α chains: electron transfer parameters and rates

Hemoglobin-mediated transport of dioxygen (O₂) critically depends on the stability of the reduced (Fe²⁺) form of the heme cofactors. Some protein mutations stabilize the oxidized (Fe³⁺) state (methemoglobin, Hb M), causing methemoglobinemia, and can be lethal above 30%. The majority of the analyses of factors influencing Hb oxidation are retrospective and give insights only for inner-sphere mutations of heme (His58, His87). Herein, we report the first all-atom molecular dynamics simulations on both redox states and calculations of the Marcus electron transfer (ET) parameters for the α chain Hb oxidation and reduction rates for Hb M. The Hb wild-type (WT) and most of the studied α chain variants maintain globin structure except the Hb M Iwate (H87Y). The mutants forming Hb M tend to have lower redox potentials and thus stabilize the oxidized (Fe³⁺) state (in particular, the Hb Miyagi variant with K61E mutation). Solvent reorganization (λ_solv 73-96%) makes major contributions to reorganization free energy, whereas protein reorganization (λ_prot) accounts for 27-30% except for the Miyagi and J-Buda variants (λ_prot ∼4%). Analysis of heme-solvent H-bonding interactions among variants provide insights into the role of Lys61 residue in stabilizing the Fe²⁺ state. Semiclassical Marcus ET theory-based calculations predict experimental k_ET for the Cyt b5-Hb complex and provide insights into relative reduction rates for Hb M in Hb variants. Thus, our methodology provides a rationale for the effect of mutations on the structure, stability, and Hb oxidation reduction rates and has potential for identification of mutations that result in methemoglobinemia.

A Case of COVID-19-Associated Autoimmune Hemolytic Anemia With Hyperferritinemia in an Immunocompetent Host

We report an interesting case of a middle-aged gentleman who presented with diabetic ketoacidosis (DKA) and tested polymerase chain reaction (PCR) positive for COVID-19 infection. His hospital stay was complicated by acute kidney injury, hematuria, and normocytic anemia. Initial chest x-ray demonstrated bibasilar opacities. D-dimer and C-reactive protein were elevated. During his hospital stay, his hemoglobin decreased from 13.4 g/dL to 9 g/dL, and further workup demonstrated ferritin of 49,081 ng/mL with lactate dehydrogenase of 1665 U/L. He was treated with prednisone and folic acid for autoimmune hemolytic anemia (AIHA). Ferritin was downtrended, and hemoglobin stabilized. As demonstrated by this case report and prior literature review, COVID-19 infection can be associated with AIHA.

The Affinity of Hemoglobin for Oxygen Is Not Altered During COVID-19

Background: A computational proteomic analysis suggested that SARS-CoV-2 might bind to hemoglobin (Hb). The authors hypothesized that this phenomenon could result in a decreased oxygen (O₂) binding and lead to hemolytic anemia as well. The aim of this work was to investigate whether the affinity of Hb for O₂ was altered during COVID-19. Methods: In this retrospective, observational, single-center study, the blood gas analyses of 100 COVID-19 patients were compared to those of 100 non-COVID-19 patients. Fifty-five patients with carboxyhemoglobin (HbCO) ≥8% and 30 with sickle cell disease (SCD) were also included ("positive controls" with abnormal Hb affinity). P₅₀ was corrected for body temperature, pH, and PCO₂. Results: Patients did not differ statistically for age or sex ratio in COVID-19 and non-COVID-19 groups. Median P₅₀ at baseline was 26 mmHg [25.2-26.8] vs. 25.9 mmHg [24-27.3], respectively (p = 0.42). As expected, P₅₀ was 22.5 mmHg [21.6-23.8] in the high HbCO group and 29.3 mmHg [27-31.5] in the SCD group (p < 0.0001). Whatever the disease severity, samples from COVID-19 to non-COVID-19 groups were distributed on the standard O₂-Hb dissociation curve. When considering the time-course of P₅₀ between days 1 and 18 in both groups, no significant difference was observed. Median Hb concentration at baseline was 14 g.dl^-1 [12.6-15.2] in the COVID-19 group vs. 13.2 g.dl^-1 [11.4-14.7] in the non-COVID-19 group (p = 0.006). Among the 24 COVID-19 patients displaying anemia, none of them exhibited obvious biological hemolysis. Conclusion: There was no biological argument to support the hypothesis that SARS-CoV-2 could alter O₂ binding to Hb.