MIS-C, inherited metabolic diseases and methylmalonic acidemia: a case report and review of the literature (preprint)

Bacground Methylmalonic acidemia (MMA) secondary to mutase deficiency, mut0, is an inborn error of metabolism causing complete enzyme deficiency. Multisystem Inflammatory Syndrome in Children (MIS-C) is a hyperinflammatory syndrome characterized by fever, inflammation, multiorgan impairment that manifests 14–60 days after the SARS-CoV-2 infection in patients aged < 21 years. Case presentation We describe the clinical case of a 2-year-old child with MMA secondary to mutase deficiency, with the documented homozygous mutation c.2179 C > T of MMUT gene, associated to mut0 phenotype. One month after SARS-CoV-2 infection, he presented fever, rash, significant increase of C-reactive protein (CRP), ferritin, triglycerides, (interleukin) IL-6, PRO-BNP, compatible with the diagnosis of MIS-C. He was treated with intravenous immunoglobulins (2gr/Kg), methylprednisolone (2 mg/Kg/day), with rapid clinical improvement. Ten days later, he showed the worsening of clinical conditions, with the recurrence of fever, vasculitic rash with palmoplantar extension, further increase of ferritin (1033 ug/l), IL-6 (146 pg/ml), PRO-BNP (5117 pg/ml), triglycerides, anemia, thrombocytopenia, metabolic acidosis with hyperlactatemia (180 mg/dl), increased urinary methylmalonic acid (200 mmol/mCreat), multiorgan failure. He was treated with sodium bicarbonate, thiamine, coenzyme Q, vitamin C, methylprednisolone and anakinra (2 mg/Kg/day). Three days after the start of anakinra, he showed a significant improvement of clinical and biochemical parameters and defervescence. 20 days later, a sepsis from Staphylococcus Aureus and Candida Albicans required the interruption of anakinra, with the worsening of the clinical and haematological parameters and the exitus. Conclusions Only a few cases of patients with inherited metabolic diseases (IMD) and MIS-C are described. However, to our knowledge, this is the first case of MIS-C in MMA described. The description of these clinical cases is a precious lesson for pediatricians to manage IMD therapeutic emergencies. Anakinra must be considered as a safe treatment of choice in IMD patients with MIS-C. The use of anakinra in patients with a severe form of MMA is safe and can be employed to treat MIS-C, gaining a substantial clinical and biochemical improvement.

Evidence associating neutrophilia, lung damage, hyperlactatemia, blood acidosis, impaired oxygen transport, and mortality in critically ill COVID-19 patients (preprint)

Background: COVID-19 severity and high in-hospital mortality are often associated with severe hypoxemia, hyperlactatemia, and acidosis. Since neutrophil numbers in severe COVID-19 can exceed 80% of the total circulating leukocytes and that they are massively recruited to infected lungs, we investigated whether metabolic acidosis mediated by the glycolytic neutrophils is associated with lung damage and impaired oxygen delivery in critically ill patients. Methods: Based on prospective mortality outcome, 102 critically ill-hospitalized COVID-19 patients were divided into two groups: ICU-Survivors (ICU-S, n=36) and ICU-Non-survivors (ICU-NS, n=66). Blood samples were collected from patients and control subjects to explore correlations between neutrophil counts, lung damage, glycolysis, blood lactate, blood pH, hemoglobin oxygen saturation, and mortality outcome. We also interrogated isolated neutrophils for glycolytic activities and for apoptosis using high-throughput fluorescence imaging complemented with transcriptomic analyses. Stratified survival analyses were conducted to estimate mortality risk associated with higher lactate among predefined subgroups. Results: Neutrophil counts were consistently higher in critically ill patients while exhibiting remarkably lower apoptosis. Transcriptomic analysis revealed miRNAs associated with downregulation of genes involved in neutrophils apoptosis. Both CT lung damage scores and neutrophil counts predicted mortality. Severinghaus fitting of hemoglobin oxygen saturation curve revealed a right-shift indicating lower oxygen capacity in non-survivors, which is consistent with lower blood-pH observed in the same group. Levels of blood lactate were increased in patients but significantly more in the ICU-NS relative to the control group. ROC analysis followed by Kaplan-Meyer survival analysis stratified to the obtained cut-off values showed that CT damage scores, neutrophil counts, and lactate levels are predictors of mortality within 15 days following blood collection. Conclusion: The current results implicate neutrophilia as a potential player in metabolic acidosis and deranged oxygen delivery associating SARS-CoV-2 infection thus contributing to mortality outcome.

The risk of venous thromboembolism and blood hyperlactatemia is associated with increased mortality among critically ill patients with Covid-19.

INTRODUCTION: Coronavirus disease 2019 (Covid-19) following venous thromboembolism (VTE) and blood hyperlactatemia are associated with higher mortality. However, reliable biomarkers for this association remain to be elucidated. This study investigated the associations of VTE risk and blood hyperlactatemia with mortality among critically ill Covid-19 patients admitted to the intensive care unit (ICU). METHODS: In this single-centre retrospective study, we included 171 patients aged ≥18 years with confirmed Covid-19 admitted to the ICU at a tertiary healthcare clinic in the Eastern region of Saudi Arabia between 1 March 2020 and 31 January 2021. Patients were divided into two groups: survivor and non-survivor. The survivors have been identified as the patients discharged from the ICU alive. The VTE risk was defined using a Padua prediction score (PPS) >4. The blood lactate concentration (BLC) cut-off value >2 mmol/L was used to determine the blood hyperlactatemia. RESULTS: Multi-factor Cox analysis showed that PPS >4 and BLC >2 mmol/L were more likely to be significantly associated with higher odds of ICU mortality in critically ill Covid-19 patients (hazard ratio [HR] = 2.80, 95% confidence interval [CI] = 1.00-8.08, p = 0.050; HR = 3.87, 95% CI = 1.12-13.45, p = 0.033, respectively). The Area under the Curve for VTE and blood hyperlactatemia were 0.62 and 0.85, respectively. CONCLUSION: VTE risk and blood hyperlactatemia have been associated with a higher mortality risk in critically ill Covid-19 patients who are hospitalized in the ICU in Saudi Arabia. According to our findings, these people needed more effective VTE prevention strategies based on a personalized assessment of their risk of bleeding. Moreover, persons without diabetes and other groups with a high risk of dying from COVID-19 may be recognized by measuring glucose as having elevated glucose and lactate jointly.

Blood lactate concentration in COVID-19: a systematic literature review.

Coronavirus disease 2019 (COVID-19) is an infectious respiratory condition sustained by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which manifests prevalently as mild to moderate respiratory tract infection. Nevertheless, in a number of cases the clinical course may deteriorate, with onset of end organ injury, systemic dysfunction, thrombosis and ischemia. Given the clinical picture, baseline assessment and serial monitoring of blood lactate concentration may be conceivably useful in COVID-19. We hence performed a systematic literature review to explore the possible association between increased blood lactate levels, disease severity and mortality in COVID-19 patients, including comparison of lactate values between COVID-19 and non-COVID-19 patients. We carried out an electronic search in Medline and Scopus, using the keywords "COVID-19" OR "SARS-CoV-2" AND "lactate" OR "lactic acid" OR "hyperlactatemia", between 2019 and present time (i.e. October 10, 2021), which allowed to identify 19 studies, totalling 6,459 patients. Overall, we found that COVID-19 patients with worse outcome tend to display higher lactate values than those with better outcome, although most COVID-19 patients in the studies included in our analysis did not have sustained baseline hyperlactatemia. Substantially elevated lactate values were neither consistently present in all COVID-19 patients who developed unfavourable clinical outcomes. These findings suggest that blood lactate monitoring upon admission and throughout hospitalization may be useful for early identification of higher risk of unfavourable COVID-19 illness progression, though therapeutic decisions based on using conventional hyperlactatemia cut-off values (i.e., 2.0 mmol/L) upon first evaluation may be inappropriate in patients with SARS-CoV-2 infection.