Disorders of water and electrolyte balance are common in intensive care medicine and are prognostically relevant. In the intensive care unit (ICU) setting, the underlying causes are often multifactorial and are substantially influenced by reduced kidney function, iatrogenic fluid and electrolyte administration and organ support treatment. This article provides a practice-oriented overview of the diagnostics and management of hyponatremia and hypernatremia as well as disturbances of potassium, magnesium and phosphate balance. In hyponatremia, symptom severity and the temporal course determine the need for acute treatment. The diagnostic evaluation should be primarily based on laboratory results and rely on serum and urine osmolality as well as urine sodium, as the clinical assessment of volume status is often unreliable. Most cases of hypotonic hyponatremia are caused by dysregulation of the arginine-vasopressin axis, particularly in syndrome of inappropriate antidiuresis (SIAD) or conditions with reduced effective circulating volume. Hypernatremia in the intensive care unit is frequently iatrogenic and associated with increased mortality, with urine osmolality guiding further diagnostic and treatment decisions. Potassium, magnesium, and phosphate disturbances are common and require an early cause-directed management and close monitoring to prevent severe complications.
The management of end-stage renal disease and kidney failure in patients transitioning to the immediate need for a renal replacement procedure is one of the most important tasks for nephrologists. A timely, structured and patient-centered approach is crucial for improving the clinical prognosis and preserving the quality of life. This includes an early systematic assessment of risk and progression, taking factors such as proteinuria, the decline of the estimated glomerular filtration rate (eGFR-slope) and cardiovascular comorbidities into account, in order to determine the optimal timing for an intensive counselling. In the evaluation of older adults, numerous geriatric nephrological aspects must be incorporated and weighed up. Shared decision-making is always central to this, which fully informs patients and relatives about all therapeutic options, conservative therapy, hemodialysis, peritoneal dialysis and kidney transplantation, and actively incorporates their preferences into the treatment plan. The option of pre-emptive kidney transplantation should be presented early, and by the time dialysis is started, a timely registration on the transplant waiting list should be ensured for eligible patients. In treatment management, patient-centered home dialysis modalities should, whenever possible, be placed clearly at the forefront, especially given their advantages with respect to sustainability and demographic trends. This also applies to older patients, although center-based dialysis as well as continuation of treatment within a conservative management framework remain highly valuable.
Fluid management is a fundamental component of intensive care treatment and has a major impact on the hemodynamics, organ perfusion, tissue oxygenation and prognosis of critically ill patients. This review article outlines the current diagnostic strategies for assessing the volume status using clinical parameters, laboratory markers, imaging techniques and advanced hemodynamic monitoring. In addition to static measurements, dynamic tests such as the passive leg raising test, fluid challenges, respiratory-induced stroke volume variations and end-expiratory occlusion maneuvers for identification of fluid responsiveness are presented. Furthermore, evidence-based recommendations on disease and phase -oriented fluid therapy are discussed. Particular emphasis is placed on the selection of infusion solutions. Balanced crystalloids are recommended as first-line therapy due to their physiological composition and favorable outcome data compared with 0.9% saline. The role of human albumin, especially in septic shock and patients with liver cirrhosis, is critically reviewed based on recent trials. Synthetic colloids are not recommended because of their side effect profile. An optimal fluid management in the ICU requires continuous reassessment, the integration of dynamic monitoring tools and adherence to patient-centered, evidence-based choice of infusion fluid and its amount to improve outcomes in critically ill patients.
Background Prevention of progression of chronic kidney disease (CKD) is one of the main tasks in nephrology. Question Available scientific evidence for drug treatment to halt CKD progression is discussed. Material and methods Structured literature search in PubMed. Results There is strong evidence supporting the use of angiotensin-converting enzyme (ACE) inhibitors/angiotensin II type 1 (AT1) receptor blockers in patients with confirmed CKD. Sodium-glucose transporter 2 (SGLT-2) inhibitors are particularly beneficial in proteinuric patients. The newer glucagon-like peptide 1 (GLP-1)/glucose-dependent insulinotropic polypeptide (GIP) receptor agonists and finerenone have also been shown to be effective in patients with type 2 diabetes and diabetic kidney damage. Conclusion The pharmacotherapeutic options for slowing CKD progression have expanded considerably in recent years. This is particularly true for patients with type 2 diabetes mellitus. It remains to be seen to what extent CKD patients with other underlying kidney diseases will benefit from GLP-1/GIP receptor agonists and finerenone. The role of combination therapy (fantastic four) also needs to be evaluated. Furthermore, new biomarkers are needed that can predict CKD progression better and thus enable individualized treatment.
Acute kidney injury (AKI) is a frequent complication in hospitalized patients, affecting up to 15% during the hospital stay and is an important risk factor for the development of chronic kidney disease (CKD). The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines from 2012, which are used to define AKI, suggest that women may be at greater risk for the development of AKI; however, more recent clinical studies and meta-analyses have found that men are more commonly affected in certain contexts. This article discusses the clinical settings in which biological sex affects the risk of occurrence of AKI, summarizes the current state of research and outlines possible biological mechanisms that could explain these sex-related differences. In addition, an overview of the currently limited but growing evidence on AKI in transgender individuals is presented.
Onconephrology is the study of acute and chronic kidney disease in the context of oncological diseases and their therapy. Acute kidney injury and chronic kidney disease can occur as a result of drug therapy, surgery or radiation therapy, or secondarily in the context of the underlying oncological disease. The accurate assessment of glomerular filtration rate prior to the administration of conventional chemotherapy reduces the risk of both over- and underdosing. Knowledge of the potential renal side effects of conventional chemotherapy, targeted therapies, and immunotherapies allows nephrological recommendations regarding their prevention and monitoring. Treatment of cancer in patients on dialysis and after kidney transplantation is challenging. Given the increased risk for malignancies after kidney transplantation, a sufficient waiting period has to be defined for kidney transplant candidates with a history of cancer.
The current hypertension guidelines consistently emphasize the importance of home blood pressure monitoring. In addition to confirming the diagnosis it is possible to identify clinically relevant hypertension phenotypes. A home blood pressure reading of 135/85 mm Hg is considered the threshold for arterial hypertension. Standardized conditions must also be observed for home blood pressure measurement. By documenting the home blood pressure values measured twice in both mornings and evenings over a period of (ideally) 7 days, home blood pressure readings can be assessed quickly and easily. It is essential to ensure that a validated blood pressure monitor is used. The sensor technology built into "smart technologies" allows cuffless detection of (pulse) waveforms and thus estimation of blood pressure. Validation based on a specific protocol is not necessary. Possible sources of error include bias, deviations over time and (varying) environmental conditions. For this reason, cuffless blood pressure measurement is not recommended by current hypertension guidelines. The Apple Watch takes a different approach: instead of blood pressure values it displays the message "possible hypertension." Due to its widespread use we will probably be confronted increasingly more with this issue but greater awareness and more newly diagnosed hypertensive patients can also be expected.
Primary hyperaldosteronism (PHA) is one of the more frequent causes of secondary hypertension. The diagnostics currently contain three steps: screening, confirmatory tests and localization tests. The screening for PHA with the aldosterone-renin ratio (ARR) has considerably increased the number of diagnosed cases in recent years; however, the accuracy of the ARR is not yet satisfactory. The number of false positive or borderline findings is relatively high. The confirmatory tests after positive screening (e. g., intravenous or oral salt loading, the fludrocortisone or the captopril test) are also not yet sufficiently accurate. This is also true for the localization procedures after confirmation of the diagnosis of PHA that are necessary to discriminate between unilateral and bilateral disease. Bilateral disease requires drug treatment but in cases of unilateral disease first the potential success of an operative intervention is assessed. Adrenal vein blood sampling, which has so far been regarded as the gold standard, is invasive and prone to errors. More recent studies on the use of positron emission tomography (PET)-computed tomography (CT) with pentixafor suggest that the localization procedures, which are necessary to plan the appropriate treatment, will be more practicable in the future. It is to be expected that the pharmacotherapy of PHA will be markedly improved by the use of the newly developed aldosterone synthase inhibitors.
Osmolality disorders are disturbances in the water balance. When the amount of water increases relative to the amount of solutes or osmoles, the osmole concentration decreases. In contrast, when the amount of water decreases relative to the amount of osmoles, the concentration increases. As sodium is the main osmolyte in the extracellular space, disturbances in water balance manifest as changes in the plasma sodium concentration. In the clinical practice osmolality disorders (water) must be distinguished from volume disorders (salt) and combinations of both disorders must be recognized. Hypotonic hyponatremia is the most frequent osmolality disorder and even the most frequent electrolyte disorder overall. Knowledge of the causes, clinical symptoms and treatment strategies is essential for the optimal management of patients with hyponatremia.
The indications to initiate acute renal replacement therapy (ARRT) include treatment refractory disturbances of the electrolyte, acid-base or fluid status as well as severe clinical symptoms of the uremic syndrome. In most other cases a watch and wait strategy is justified, provided that a clinical re-evaluation is performed at least daily; however, if the clinical situation and trajectory of the disease suggest that ARRT will be necessary, treatment should be initiated even in the absence of urgent indications. Continuous and intermittent modalities should be used as complementary procedures. For anticoagulation a regional citrate or systemic heparin (mostly with unfractionated heparin) can be used in most cases. Guidelines recommend a total effluent volume (dialysate plus filtrate) of 20-25 ml/kg/h for continuous ARRT, which will usually require a higher prescription of effluent volume. Weaning from ARRT can be attempted in patients with stable hemodynamics, fluid, electrolyte and acid-base status who have regained a relevant urine output (> 300-600 ml/24 h).
