This chapter discusses the diagnosis, evaluation and management of renal emergencies including metabolic acidosis, metabolic alkalosis, respiratory acidosis and respiratory alkalosis. The symptoms depend on the severity and etiology of the underlying acidosis, and are often nonspecific. Altered mental status, weakness, nausea, and abdominal pain are common. Hyperkalemia is often present due to transcellular shift of K-plus out of cells and H-plus into cells. Kussmaul respirations are classically associated with diabetic ketoacidosis (DKA), and refer to rapid, deep breathing. The critical presentation includes extreme acidemia that leads to neurological dysfunction (severe obtundation, coma, and seizures) as well as cardiovascular complications (arrhythmias, decreased cardiac contractility, arteriolar vasodilation, and decreased responsiveness to catecholamines). Profound hypotension and shock can result, which can complicate management since hypotension and shock are often the cause of the acidosis. If acidosis is due to DKA, treatment requires insulin and IV fluid resuscitation.