Core Curriculum in Nephrology
Installments of the Core Curriculum in Nephrology provide trainees in nephrology with a strong knowledge base in core topics in the specialty by providing an overview of the topic and citing key references, including the foundational literature that led to current clinical approaches.
- Metabolic alkalosis is a widespread acid-base disturbance, especially in hospitalized patients. It is characterized by the primary elevation of serum bicarbonate and arterial pH, along with a compensatory increase in Pco2 consequent to adaptive hypoventilation. The pathogenesis of metabolic alkalosis involves either a loss of fixed acid or a net accumulation of bicarbonate within the extracellular fluid. The loss of acid may be via the gastrointestinal tract or the kidney, whereas the sources of excess alkali may be via oral or parenteral alkali intake.
- The management of immunosuppression utilized in glomerular diseases requires highly nuanced care. Timely recognition and management of these disorders is essential to mitigate the extent of kidney damage. This involves being cognizant of the various classes of immunosuppression, which includes alkylating agents, antimetabolites, calcineurin inhibitors, anti-CD20 therapy, complement inhibitors, corticosteroids, and intravenous immunoglobulin. The mechanisms of action of these drugs, along with associated pharmacokinetics and pharmacodynamics, facets of monitoring, and adverse effects are important aspects with which nephrologists are required to be well versed.
- Volume overload, defined as excess total body sodium and water with expansion of extracellular fluid volume, characterizes common disorders such as congestive heart failure, end-stage liver disease, chronic kidney disease, and nephrotic syndrome. Diuretics are the cornerstone of therapy for volume overload and comprise several classes whose mechanisms of action, pharmacokinetics, indications, and adverse effects are essential principles of nephrology. Loop diuretics are typically the first-line treatment in the management of hypervolemia, with additional drug classes indicated in cases of diuretic resistance and electrolyte or acid-base disorders.
- The kidney biopsy is an essential tool for diagnosis of many kidney diseases. Obtaining an adequate biopsy sample with appropriate allocation for various studies is essential. Nephrologists should understand key lesions and their interpretation because these are essential elements underlying optimal approaches for interventions. This installment in the AJKD Core Curriculum in Nephrology will review these topics. We will first briefly discuss considerations for allocation and processing of kidney biopsies.
- Poisoning is a common problem in the United States. Acid-base disturbances, electrolyte derangements, or acute kidney injury result from severe poisoning from toxic alcohols, salicylates, metformin, and acetaminophen. Lithium is highly sensitive to small changes in kidney function. These poisonings and drug overdoses often require the nephrologist’s expertise in diagnosis and treatment, which may require correction of acidosis, administration of selective enzyme inhibitors, or timely hemodialysis.
- As chronic kidney disease (CKD) progresses, the requirements and utilization of different nutrients change substantially. These changes are accompanied by multiple nutritional and metabolic abnormalities that are observed in the continuum of kidney disease. To provide optimal care to patients with CKD, it is essential to have an understanding of the applicable nutritional principles: methods to assess nutritional status, establish patient-specific dietary needs, and prevent or treat potential or ongoing nutritional deficiencies and derangements.
- The lungs and kidneys are cooperative and interdependent organs that secure the homeostasis of the body. Volume and acid–base disorders sit at the nexus between these two systems. However, lung–kidney interactions affect the management of many other conditions, especially among critically ill patients. Therefore, management of one system cannot proceed without a thorough understanding of the physiology of the other. This installment of AJKD’s Core Curriculum in Nephrology discusses the complex decision-making required in treating concomitant respiratory and kidney disorders.
- The most common cause of kidney failure in the United States and across the world is diabetes mellitus (DM). Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in persons with diabetes, and chronic kidney disease (CKD) further increases overall CVD risk. It is important to individualize glycemic targets for patients to maintain glucose levels that will reduce the development and progression of complications while avoiding hypoglycemia. CKD alters the relationship of glucose levels to measures of long-term control, such as hemoglobin A1c.
- In the early days of dialysis, because of a lack of existing in-center infrastructure, home hemodialysis (HHD) was frequently used to expand dialysis programs. Recently, HHD has been thrust into the spotlight of kidney care programs once again. Patients and policymakers are demanding more choices for the management of kidney failure while controlling for cost. Perhaps it is not surprising that the kidney community's interest in HHD has been revived, especially during the COVID-19 pandemic. To meet this increased interest and demand, nephrologists and dialysis providers must embrace new technologies and improve their understanding of HHD systems.
- Assessment of glomerular filtration rate (GFR) is fundamental to clinical practice, public health, and research. The kidney has several critical functions; GFR is used as an overall assessment of these kidney functions. GFR is used to diagnose, stage, and manage chronic kidney disease (CKD); ascertain the prognosis for chronic kidney disease–related events and mortality; and determine drug dosages. GFR is the rate at which the glomerulus filters plasma to produce an ultrafiltrate and can be assessed from clearance or serum levels of filtration markers.
- The anion gap (AG) is a mathematical construct that compares the blood sodium concentration with the sum of the chloride and bicarbonate concentrations. It is a helpful calculation that divides the metabolic acidoses into 2 categories: high AG metabolic acidosis (HAGMA) and hyperchloremic metabolic acidosis—and thereby delimits the potential etiologies of the disorder. When the [AG] is compared with changes in the bicarbonate concentration, other occult acid-base disorders can be identified. Furthermore, finding that the AG is very small or negative can suggest several occult clinical disorders or raise the possibility of electrolyte measurement artifacts.
- Medications are an important part of the management of patients with kidney disease. When used appropriately, pharmacotherapy can slow disease progression and reduce morbidity and mortality. Unfortunately, reduced kidney function can significantly alter the pharmacokinetics and pharmacodynamics of many medications, putting patients at risk for drug toxicity if modifications to therapy are not appropriately managed. Adding complexity to the appropriateness of medication and dosage selection is the difficulty in estimating kidney function and the discordance between the Cockcroft-Gault–derived dosing cut points in most medication package inserts and the estimations of glomerular filtration rate by newer and generally more accurate guideline-recommended equations.
- Immunoglobulin A nephropathy (IgAN) is the most common primary glomerular disease worldwide. The diagnostic histologic hallmark is dominant or codominant IgA staining on kidney biopsy; however, patients may present with various clinical syndromes ranging from asymptomatic abnormalities noted on urinalysis to rapidly progressive glomerulonephritis. Given substantial heterogeneity in the clinical course of disease, online risk calculators are available that may assist in prognostication and inform discussions with patients.
- Urinary diversion after cystectomy has been a historical standard for the treatment of numerous benign and malignant diseases of the bladder. Since the first published description in the early 1900s, improvements in surgical technique and a better understanding of the metabolic sequelae postoperatively have greatly enhanced patient outcomes. Both continent and incontinent diversions are available to patients after cystectomy. In appropriately selected patients, orthotopic neobladder reconstruction can offer preservation of body image and continence, and continent cutaneous diversions represent a reasonable alternative.
- An estimated 8% to 16% of the world’s population has chronic kidney disease, defined by low glomerular filtration rate or albuminuria. Progression of chronic kidney disease is associated with adverse outcomes, including incident kidney failure with replacement therapy, accelerated cardiovascular disease, disability, and mortality. Therefore, slowing kidney function decline is paramount in the management of a patient with chronic kidney disease. Ascertaining the cause of kidney disease is an important first step and may compel specific therapies.
- Since maintenance hemodialysis (HD) first became available in the United States in 1962, there has been tremendous growth in the population of patients with kidney failure. HD has become a routine treatment carried out in outpatient clinics, hospitals, nursing facilities, and in patients’ homes. Although it is a complex procedure, HD is quite safe. Serious complications are uncommon due to the use of modern HD machines and water treatment systems as well as the development of strict protocols to monitor various aspects of the HD treatment.
- The understanding and management of membranous nephropathy, a common cause of nephrotic syndrome that is more frequently encountered in adults than in children, has rapidly evolved over the past decade. Identification of target antigens has allowed for more precise molecular diagnoses, and the ability to monitor circulating autoantibodies has added a new vantage point in terms of disease monitoring and decisions about immunosuppression. Although immunosuppression with alkylating agents combined with corticosteroids, or with calcineurin inhibitor–based regimens, has been the historical mainstay of treatment, observational and now randomized controlled trials with the B-cell–depleting agent rituximab have moved this agent to the forefront of therapy for primary membranous nephropathy.
- Renal cystic disease encompasses a large variety of illnesses with various phenotypic expressions that can manifest in utero, in infancy, and in childhood. These diseases may be unilateral or bilateral and present with single or multiple cysts. Various cystic diseases may also progress to chronic kidney disease (CKD), including kidney failure, and hepatic disease, thus potentially being life threatening. The prevalence and serious complications of CKD in the pediatric population make it vital that health care providers detect these conditions early and provide effective management.