The most common cause of renal artery stenosis is atherosclerosis, the same condition that causes narrowing of the arteries in coronary heart disease and stroke, and the risk factors are the same as well. Cholesterol plaques build up along the walls of the renal artery and gradually cause narrowing.
Oxytocin is a commonly used uterotonic that can cause significant and even fatal hypotension, particularly when given as a bolus. The resulting hypotension can be produced by a decrease in systemic vascular resistance or cardiac output through a decrease in venous return.
Thus hypomagnesemia results in an increased intracellular calcium level. This inhibits the release of parathyroid hormone, which can result in hypoparathyroidism and hypocalcemia. Furthermore, it makes skeletal and muscle receptors less sensitive to parathyroid hormone.