A mathematical approach to severe hyponatremia and hypernatremia in renal replacement therapies.

Severe dysnatremias are perplexing problems in patients undergoing renal replacement therapy on a chronic or acute basis. The ability to manipulate sodium concentration in the dialysate or replacement solutions is limited. Compounding dialysate or replacement fluids to alter sodium concentration could result in errors. Rapid correction of hyponatremia or hypernatremia due to equilibrium with dialysate or replacement solutions could lead to osmotic demyelination syndrome or cerebral edema respectively. Continuous renal replacement therapy is the preferred dialysis modality in patients with severe dysnatremias. In this article, we present simple formulas to determine the rate of hypotonic or hypertonic solutions needed to mitigate rapid correction of dysnatremias. These formulas can be used readily by the clinician at bedside.

Eduardo Slatopolsky: A Pioneer in the Field of Mineral and Bone Disorders in Kidney Disease.

Eduardo Alberto Slatopolsky (1934-2024), Washington University Joseph Friedman Professor Emeritus of Medicine, a prominent physician-scientist, was born in Buenos Aires, Argentina. The impact of his research in the area of mineral and bone disorders in kidney disease has been profound for over 50 years starting in the 1960s. He was a global authority on secondary hyperparathyroidism. He was instrumental in illustrating the role of hyperphosphatemia in chronic kidney disease (CKD) and in developing the first reliable parathyroid hormone (PTH) assay. His research led to the utilization of calcium salts as phosphate binders replacing the toxic aluminum salts. Moreover, he illustrated the role of vascular calcifications in CKD patients, paving the way for non-calcium phosphate binders. He proposed the use of calcitriol and later vitamin D analogs in the management of secondary hyperparathyroidism, which is the current standard of care. He demonstrated the decreased expression of the calcium-sensing receptor in parathyroid tissue in CKD patients. Dr. Slatopolsky's global legacy will last for generations.

New Trends in the Diagnosis and Management of Hypertension.

Hypertension is the leading risk factor for disability and death globally. This is attributed to two major complications of hypertension, cerebrovascular accidents (CVA) and ischemic heart disease. This update provides a concise overview of several timely hypertension topics. These topics were chosen based on recent significant advances in the field. Examples include the use of renin-angiotensin-aldosterone inhibitors in coronavirus disease 2019 (COVID-19) patients, the landmark Systolic Blood Pressure Intervention Trial (SPRINT), management of resistant hypertension, and primary aldosteronism. The articles reviewed also include other recent landmark clinical trials, prior clinical trials of great significance, and medical societies guidelines. Ten topics were chosen based on their relevance to the practicing clinician. Each topic is discussed in a condensed manner highlighting recent advances in the field of hypertension.

Severe Rhabdomyolysis Due to Strenuous Exercise With a Potential Role of a High-Caffeine Energy Drink.

Caffeine is the core ingredient in energy drinks. These drinks are commonly consumed by athletes around the time of their workout to boost energy levels. The patient in the case presented is a 40-year-old-man who developed severe rhabdomyolysis after consuming an energy drink with high content of caffeine prior to a strenuous workout. He was successfully treated with isotonic intravenous solutions. Clinicians should be aware of the potential adverse reactions associated with the use of energy drinks.

New Trends in the Utilization of Intravenous Fluids.

Intravenous fluids (IVFs) are the most commonly used drugs in hospitalized patients. Knowledge of the indications and pharmacokinetics of IVFs is critical for all medical disciplines. Isotonic saline (normal saline, 0.9% NS) is the most utilized intravenous solution. Isotonic saline effectively expands the intravascular compartment, as one-quarter of the infusate goes intravascularly, while the remaining three-quarters go into the interstitial space. The proper use of IVFs in different clinical scenarios is paramount. IVFs differ with regard to their half-life, intravascular volume expansion, preparation, and cost. Crystalloids are more commonly utilized due to their relatively low cost and availability. Colloids are very advantageous in cases of shock or hemorrhage, as they remain in the intravascular space, thus facilitating an increase in blood pressure (BP) prior to blood administration. Colloids are also advantageous in cases of burns and severe hypoglobulinemia. Human albumin (5%, 20%, and 25%) is the most used colloid solution. It remains intravascularly provided and there is no capillary leak as in systematic inflammation. The goal in hospitalized patients is timely and adequate intravenous fluid resuscitation. Utilization of a large volume of isotonic saline may lead to hypervolemia, hypernatremia, hyperchloremia, metabolic acidosis, and hypokalemia. The use of balanced intravenous solutions has been advocated to avoid these complications.

Disorders of Calcium Metabolism: Hypocalcemia and Hypercalcemia.

Calcium (Ca+2) is a divalent cation that plays a critical role in numerous body functions such as skeletal mineralization, signal transduction, nerve conduction, muscle contraction, and blood coagulation. Ca+2 metabolism is linked to magnesium (Mg+2) and phosphate metabolism. Ca+2 homeostasis is dependent on intestinal absorption, bone turnover, and renal reabsorption. The hormonal regulators of these processes are the parathyroid hormone (PTH), calcitriol {1,25-dihydroxyvitamin D [1,25(OH)2D]}, and serum ionized Ca+2. Cloning of the Ca+2-sensing receptor (CaSR) has greatly advanced the understanding of Ca+2 metabolism. Disorders of Ca+2 metabolism are easily recognized because Ca+2 is included in routine chemistry panels. Measurement of ionized Ca+2 is the preferred way to ascertain the diagnosis of hypocalcemia and hypercalcemia.

Pathophysiology, Evaluation, and Management of Metabolic Alkalosis.

Metabolic alkalosis is an increase in blood pH to >7.45 due to a primary increase in serum bicarbonate (HCO3 -). Metabolic alkalosis results from alkali accumulation or acid loss, and it is associated with a secondary increase in carbon dioxide arterial pressure (PaCO2). Metabolic alkalosis is a common acid-base disorder, especially in critically ill patients. The pathogenesis of chronic metabolic alkalosis includes two derangements, generation of metabolic alkalosis via gain of alkali or loss of acid and maintenance of metabolic alkalosis by increased tubular HCO3 - reabsorption (failure of the kidneys to excrete excess alkali). Metabolic alkalosis is the most common acid-base disorder in hospitalized patients, particularly in the surgical critical care unit. Mortality increases as pH increases.

Update on the etiology, classification, and management of glomerular diseases.

In this brief review, the reader will find a timely update regarding some of the most commonly encountered glomerular diseases. The review will include an update on the etiology with a focus on new genetic and molecular discoveries. New classifications will be elucidated, and management will be updated in broad strokes. Illustrative pathology slides will be used as appropriate. It is critical for the reader to realize from the outset that terminology such as focal segmental glomerulosclerosis and crescentic glomerulonephritis represent a pattern of injury rather than a specific disease. Whenever possible, the specific etiology and pathogenesis of a given pattern should be sought. It is also important to know that the same disease or mechanism can cause multiple patterns of injury, whereas the same pattern of injury can be the result of multiple disease or mechanisms.

Nephrotoxicity of Immune Checkpoint Inhibitors: Acute Kidney Injury and Beyond.

Immune checkpoint inhibitors (ICIs) are novel humanized monoclonal antibodies that release the brakes on the immune system, resulting in the destruction of tumor cells. ICIs are approved for a variety of hematological and solid organ malignancies, and the list has been growing since the approval of ipilimumab in 2011. ICIs are associated with a variety of immune-related adverse events (irAEs). irAEs commonly affect the skin, the gastrointestinal (GI) tract, and the endocrine system. Acute kidney injury (AKI) due to ICIs (ICI-AKI) occurs in a minority of patients, and it is usually due to acute tubulointerstitial nephritis (ATIN). Treatment with corticosteroids is usually successful. There have been reports of electrolyte disorders due to ICIs, including hyponatremia, hypocalcemia, hypokalemia, and Fanconi syndrome. The diagnosis of electrolyte disorders requires vigilance and routine laboratory monitoring.

Unusual Case of Localized Upper Limbs and Truncal Edema Associated with Fever, Anemia, and Acute Kidney Injury.

The patient is a 75-year-old man who presented with right arm pain, edema, and erythema. The same manifestations appeared in the other arm 3 weeks later. He also developed fever, acute kidney injury, anemia, and truncal edema. Initial extensive evaluation was unrevealing. He was noted to have elevated creatine kinase, and a diagnostic muscle biopsy lead to diagnosis of inflammatory myositis. He improved with corticosteroids.