The Association of Inflammatory Cytokines in the Pulmonary Pathophysiology of Respiratory Failure in Critically Ill Patients With Coronavirus Disease 2019.

OBJECTIVES: The majority of coronavirus disease 2019 mortality and morbidity is attributable to respiratory failure from severe acute respiratory syndrome coronavirus 2 infection. The pathogenesis underpinning coronavirus disease 2019-induced respiratory failure may be attributable to a dysregulated host immune response. Our objective was to investigate the pathophysiological relationship between proinflammatory cytokines and respiratory failure in severe coronavirus disease 2019. DESIGN: Multicenter prospective observational study. SETTING: ICU. PATIENTS: Critically ill patients with coronavirus disease 2019 and noncoronavirus disease 2019 critically ill patients with respiratory failure (ICU control group). INTERVENTIONS: Daily measurement of serum inflammatory cytokines. MEASUREMENTS AND MAIN RESULTS: Demographics, comorbidities, clinical, physiologic, and laboratory data were collected daily. Daily serum samples were drawn for measurements of interleukin-1ß, interleukin-6, interleukin-10, and tumor necrosis factor-α. Pulmonary outcomes were the ratio of Pao2/Fio2 and static lung compliance. Twenty-six patients with coronavirus disease 2019 and 22 ICU controls were enrolled. Of the patients with coronavirus disease 2019, 58% developed acute respiratory distress syndrome, 62% required mechanical ventilation, 12% underwent extracorporeal membrane oxygenation, and 23% died. A negative correlation between interleukin-6 and Pao2/Fio2 (rho, -0.531; p = 0.0052) and static lung compliance (rho, -0.579; p = 0.033) was found selectively in the coronavirus disease 2019 group. Diagnosis of acute respiratory distress syndrome was associated with significantly elevated serum interleukin-6 and interleukin-1ß on the day of diagnosis. CONCLUSIONS: The inverse relationship between serum interleukin-6 and Pao2/Fio2 and static lung compliance is specific to severe acute respiratory syndrome coronavirus 2 infection in critically ill patients with respiratory failure. Similar observations were not found with interleukin-ß or tumor necrosis factor-α.

Macrotroponin causing elevation in cardiac troponin I.

We report a case of macrotroponin causing persistently raised levels of cardiac troponin I (cTnI) in a 57-year-old man with recurrent atypical chest pain. Macrotroponin, a troponin-immunoglobulin complex, should be considered when cTnI values are inconsistent with the clinical picture, and fail to demonstrate a rise and/or fall pattern in suspected cases of acute coronary syndrome. Clear and effective communication between cardiologists and laboratorians is essential in the management of patients with macrotroponin.

Recurrent hypoglycemia from insulin autoimmune syndrome.

Insulin autoimmune syndrome (IAS) is an uncommon cause of hyperinsulinemic hypoglycemia characterized by autoantibodies to endogenous insulin in individuals without previous exposure to exogenous insulin. IAS is the third leading cause of spontaneous hypoglycemia in Japan, and is increasingly being recognized worldwide in non-Asian populations. We report a case of IAS in a Caucasian woman with recurrent complaints of hypoglycemia, with laboratory findings of serum glucose 2.5 mmol/L (45 mg/dL), insulin 54,930 pmol/L (7,909 µIU/mL), connecting peptide (C-peptide) 4,104 pmol/L (12.4 ng/mL), and a corresponding insulin to C-peptide molar ratio of 13.4 during a spontaneous hypoglycemic event. Autoantibodies to insulin were markedly elevated at > 50 kU/L (> 50 U/mL). IAS should be considered in the differential diagnosis of hypoglycemia in non-diabetic individuals. Distinction from insulinoma is especially crucial to prevent unwarranted invasive procedures and surgical interventions in hypoglycemic patients.