This is a series of review articles on disorders of fluids and electrolytes. Each is accompanied by a case challenge that highlights the issues raised in the review article.
This review considers the physiological principles that guide the appropriate selection of intravenous fluids in acutely ill patients, as well as the recent literature evaluating the safety of various intravenous fluids.
- CME
A 72-year-old man with long-standing heart failure is admitted to the hospital. Laboratory results include plasma sodium 133 mmol/L, potassium 3.3 mmol/L, chloride 94 mmol/L, carbon dioxide 30 mmol/L, and creatinine 1.6 mg/dL. What is the best strategy to support this patient?
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
Electrolyte disturbances are common in patients with diabetes mellitus. This review highlights the ways in which specific electrolytes may be influenced by the dysregulation of glucose homeostasis.
A 28-year-old man presents with diabetic ketoacidosis after an influenza-like illness. Lab values include: sodium 144 mmol/L, potassium 5.7 mmol/L, chloride 98 mmol/L, sodium bicarbonate 13 mmol/L, creatinine 1.5 mg/dL, BUN 30 mg/dL, glucose 702 mg/dL, and venous pH 7.2. What is the best strategy to support this patient?
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
The plasma potassium level is normally maintained within narrow limits by multiple mechanisms. This article reviews the mechanisms that regulate potassium homeostasis and describes the important role that the circadian clock exerts on these processes.
- CME
A 7-year-old boy with a history of hyperchloremic metabolic acidosis presented with nausea, vomiting, and muscle weakness. Lab data include: sodium 136 mmol/L, potassium 1.9 mmol/L, chloride 110 mmol/L, bicarbonate 16 mmol/L, anion gap 10, blood urea nitrogen 10 mg/dL, creatinine 0.4 mg/dL, blood pH 7.32, and PCO2 25 mm Hg. What is the best strategy to support this patient?
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
This review summarizes the salient discoveries that culminated in the development of vasopressin antagonists, focusing on their actions, side effects, emerging safety concerns, and important gaps in data. The review also considers how and when to use these agents.
- CME
A 57-year-old woman presents for the third time with hyponatremia. Lab data include: blood pressure 126/78 mm Hg, plasma sodium 125 mmol/L, urinary sodium 122 mmol/L, blood urea nitrogen 16 mg/dL, and glucose 90 mg/dL. What is the best strategy to support this patient?
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
This article reviews the classic, integrative principles of water balance. This model is used to discuss the role of underlying genes and gene products (proteins) in water balance and to provide a mechanistic basis for decisions about related disorders.
A 53-year-old woman with chronic kidney disease, hypertension, and a mood disorder presents with irritability and pressured speech. Lab data include: blood pressure 130/85 mm Hg, plasma sodium 155 mmol/L, potassium 4.5 mmol/L, blood urea nitrogen 67 mg/dL, creatinine 1.99 mg/dL, glucose 90 mg/dL, and plasma osmolality 339 mOsm/L.
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
This review focuses on the safe removal of excess hydrogen ions, the administration of sodium bicarbonate, and the possible contribution of intracellular acidosis to the development of cerebral edema in patients with diabetic ketoacidosis.
- CME
A 15-year-old boy with nephrotic syndrome presents with abdominal pain and vomiting. Lab data include: blood glucose 849 mg/dL, blood pH 7.19, PCO2 18 mm Hg, PO2 40 mm Hg, bicarbonate 7 mmol/L, sodium 125 mmol/L, potassium 6.2 mmol/L, chloride 81 mmol/L, and total carbon dioxide 8 mmol/L.
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
This review considers the causes and consequences of an abnormal plasma sodium concentration and offers a framework for correcting it.
- CME
A 55-year-old woman presents in a confused state with a plasma sodium of 112 mmol/L and potassium of 2.6 mmol/L. Urine osmolality is 630 mOsm per kilogram of water, and urinary sodium level is 12 mmol/L.
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
When lactic acidosis accompanies low-flow states or sepsis, mortality rates increase sharply. This review summarizes our current understanding of the pathophysiological aspects of lactic acidosis, as well as the approaches to its diagnosis and management.
- CME
A 60-year-old man with diabetes, hypertension, and chronic kidney disease presents with abdominal pain and confusion. Lab data include: blood pH 6.68, PCO2 18 mm Hg, PO2 73 mm Hg, sodium 146 mmol/L, potassium 6.3 mmol/L, chloride 83 mmol/L, and bicarbonate <2.0 mmol/L.
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
This review, which describes an approach to acid–base disorders, incorporates insights and examples drawn from the traditional, bicarbonate-centered approach and the physicochemical, or strong ion, approach.
- CME
A 64-year-old man with agitation and a history of alcohol abuse has been brought to the emergency department. His laboratory data include: blood pH 7.07, PCO2 12.6 mm Hg, PO2 55 mm Hg, sodium 133 mmol/L, potassium 4.1 mmol/L, chloride 93 mmol/L, and bicarbonate 3.9 mmol/L.
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
Acid–base homeostasis is fundamental for maintaining life. This article reviews a stepwise method for the physiological approach to evaluation of acid–base status.
- CME
A 22-year-old woman awaiting transfer to the operating room for stabilization of injuries suffered in a car accident has received 6 liters of isotonic saline. The lab values include blood pH 7.28, PCO2 39 mm Hg, sodium 135 mmol/L, potassium 3.8 mmol/L, chloride 115 mmol/L, and bicarbonate 18 mmol/L.
See the full description of the case along with polling results, comments, and the editor’s recommendations.
- Comments
- Poll
A new series of review articles that consider approaches to the understanding and management of fluid, electrolyte, and acid–base disorders is introduced in this editorial by the editor of the series. These disorders are among the most common conditions that we encounter as clinicians. Two weeks before publication of each review article, a short case will be posted at NEJM.org, accompanied by questions about the diagnosis and management of the condition to be considered. We encourage you to read the case and tell us how you would manage the patient’s treatment.
