ABSTRACT
Rivers are globally significant natural sources of atmospheric methane (CH4). However, the effect of land use changes on riverine CH4 dynamics, particularly in tropical zones, remain ambiguous, yet important to predict and anticipate the present and future contribution of rivers to the global CH4 budget. The present study examines the magnitude and drivers of riverine CH4 concentration and emission in the tropical Krishna River (KR) basin, India. The large spatial variability of CH4 concentration (0.03 to 185.34 µmol L -1) and emissions (0.04 mmol m-2 d-1 to 1666.24 mmol m-2 d-1) in the KR basin was linked to the site-specific features of the catchments through which rivers are draining. Several fold higher CH4 concentration and emission was observed for the urban river sites (64.63 ± 53.17 µmol L-1 and 294.15 ± 371.52 mmol m2 d-1, respectively) than the agricultural (1.05 ± 2.22 µmol L-1 and 3.45 ± 9.72 mmol m2 d-1, respectively) and forested (0.49 ± 0.23 µmol L-1 and 1.26 ± 0.73 mmol m2 d-1, respectively) sites. The concentrations of dissolved oxygen, total phosphorus, and Chlorophyll-a were significant hydrochemical variables strongly coupled with the dissolved CH4 concentrations. On the other hand, percentage of built-up area emerged as the most important landscape-level driver indicating that urbanization has an overriding effect on riverine CH4 concentration in the agriculture dominated KR basin. Our study supports the growing notion that tropical urban rivers are hotspot of CH4 emission. Furthermore, we show that the pattern of increasing in riverine CH4 concentration with built-up area (%) is a general feature of Asian river basins. As the urban land cover and population following an exponential increase, Asian rivers might contribute substantially to the regional and global CH4 budget.
Subject(s)
Methane , Rivers , Urbanization , Chlorophyll A , IndiaABSTRACT
The serum osmolar gap, defined as the difference between measured osmolality and calculated osmolarity, is a convenient method to screen for toxins in serum. In normal circumstances, the difference between the two is 6-10 mol/kg. Typical contributors to serum osmolarity are sodium bicarbonate, sodium chloride, glucose and urea. An elevated gap, defined as a difference >10 mol/kg, can occur if a sufficient quantity of an additional solute other than those mentioned above is present in the serum or there are inaccuracies in sodium measurement secondary to hyperlipidaemia and hyperproteinaemia. An elevated serum osmolar gap should thus prompt clinicians to check for toxic alcohol levels. Treatment with fomepizole should not be delayed if suspicion is high. Isolated diabetic ketoacidosis can occasionally present with an elevated osmolar gap in the absence of concomitant alcohol ingestion. This finding is attributed to the production of acetone and glycerol. We describe the case of a 62-year-old man presenting with diabetic ketoacidosis/hyperosmolar hyperglycaemic state and an elevated osmolar gap in the absence of toxic alcohol ingestion. LEARNING POINTS: The osmolar gap is the difference between the measured and the calculated serum osmolarity and should be calculated in all patients presenting with elevated serum osmolarity; if elevated, toxic alcohol ingestion should be considered and prophylactic treatment with fomepizole immediately administered if the index of suspicion is high.Although toxic alcohol ingestion is one of the common causes of an elevated osmolar gap, hyperlipidaemia, hyperproteinaemia and less occasionally lactic acidosis and ketoacidosis have also been implicated.In the setting of ketoacidosis, the osmolar gap can be elevated in the absence of toxic alcohol ingestion, is attributed to increased production of acetone and glycerol, and is responsive to treatment with insulin and intravenous fluids.
ABSTRACT
Diabetic ketoacidosis (DKA) is a significant complication of poorly controlled diabetes. In diabetics, it typically occurs due to insulin deficiency resulting in lipolysis and subsequent ketone body formation and acidosis. The emergence of the COVID-19 infection has been associated with several complications, with the most prominent being pulmonary and cardiovascular-related. However, in some cases, patients with COVID-19 infection present with diabetic ketoacidosis. The pathophysiology of DKA in COVID-19 infection is different and currently not completely understood. The manifestation of DKA in COVID-19 patients is associated with increased severity of mortality and length of stay in these patients. Here, we describe a patient with no past medical history who presented with COVID-19 symptoms and was found to be in DKA. This case report highlights the possible underlying pathophysiology associated with this complication.
ABSTRACT
Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Clinical manifestations are diverse and can vary from mild respiratory symptoms to severe hypoxic respiratory failure. In severe cases, infection can cause gastrointestinal, renal, cardiac, neurological and haematological complications and result in multi-organ failure. There are very few reports of parapneumonic effusion in patients with COVID-19. We describe two patients with COVID-19 who had loculated empyema and discuss the clinical course and therapeutic options. LEARNING POINTS: The clinical manifestations of COVID-19 vary from mild to severe disease and can result in multi-organ failure.Pleural empyema is usually treated with a combination of antibiotics and surgical drainage of the pleural cavity.
