Acute kidney injury (AKI) consists of a rapid renal function decline which usually increases serum urea and creatinine levels. Since kidney injury begins by inducing biological and molecular changes ...which evolve to cellular damage, biomarkers could be used as tools for monitoring early AKI appearance, and predicting its recovery. Among the main AKI biomarkers the neutrophil gelatinase-associated lipocalin, cystatin C, kidney injury molecule-1, monocyte chemotactic peptide-1, N-acetyl-β-D-glucosaminidase, interleukin-18, liver-type fatty acid-binding protein, netrin-1, cycle arrest markers, endogenous ouabain, selenium-binding protein 1, and BPIFA2 marker, have been described. Even though novel biomarkers seem to be more helpful to early detect AKI and/or predict the need for renal replacement, and mortality compared to serum creatinine, more comprehensive studies are still required to determine their clinical utility.
In addition to the structural changes in the kidney associated with aging, physiological changes in renal function are also found in older adults, such as decreased glomerular filtration rate, ...vascular dysautonomia, altered tubular handling of creatinine, reduction in sodium reabsorption and potassium secretion, and diminished renal reserve. These alterations make aged individuals susceptible to the development of clinical conditions in response to usual stimuli that would otherwise be compensated for in younger individuals, including acute kidney injury, volume depletion and overload, disorders of serum sodium and potassium concentration, and toxic reactions to water-soluble drugs excreted by the kidneys. Additionally, the preservation with aging of a normal urinalysis, normal serum urea and creatinine values, erythropoietin synthesis, and normal phosphorus, calcium and magnesium tubular handling distinguishes decreased GFR due to normal aging from that due to chronic kidney disease.
Magnesium (Mg) is the main intracellular divalent cation, and under basal conditions the small intestine absorbs 30–50% of its intake. Normal serum Mg ranges between 1.7–2.3 mg/dl (0.75–0.95 mmol/l), ...at any age. Even though eighty percent of serum Mg is filtered at the glomerulus, only 3% of it is finally excreted in the urine. Altered magnesium balance can be found in diabetes mellitus, chronic renal failure, nephrolithiasis, osteoporosis, aplastic osteopathy, and heart and vascular disease. Three physiopathologic mechanisms can induce Mg deficiency: reduced intestinal absorption, increased urinary losses, or intracellular shift of this cation. Intravenous or oral Mg repletion is the main treatment, and potassium-sparing diuretics may also induce renal Mg saving. Because the kidney has a very large capacity for Mg excretion, hypermagnesemia usually occurs in the setting of renal insufficiency and excessive Mg intake. Body excretion of Mg can be enhanced by use of saline diuresis, furosemide, or dialysis depending on the clinical situation.
Obesity and glomerular filtration rate Schwartz, Paula; Capotondo, Maria M.; Quaintenne, Miranda ...
International urology and nephrology,
05/2024, Letnik:
56, Številka:
5
Journal Article
Recenzirano
Obesity has received considerable attention in general medicine and nephrology over the last few years. This condition increases the risk of metabolic syndrome, diabetes mellitus, hypertension, and ...dyslipidemia, which are the main risk factors for developing chronic kidney disease (CKD). Kidney damage caused by obesity can be explained by many mechanisms, such as sympathetic nervous and renin-angiotensin-aldosterone systems activation, mechanical stress, hormonal unbalance, as well as inflammatory cytokines production. Even though creatinine-based glomerular filtration rate (GFR) equations in obese individuals have been validated (Salazar-Corcoran and CKD-MCQ), changes in body weight after bariatric surgery (BS) leads to changes in creatininemia, affecting its reliability. Thus, an average between creatine and cystatin-based GFR equations would be more appropriate in this setting. Bariatric surgery can reverse diabetes mellitus and improve hypertension, which are the main causes of CKD. Conclusion: GFR can be affected by obesity and BS, and its value should be cautiously evaluated in this setting.
Monoclonal gammopathy of renal significance (MGRS) is a new nosological group of entities (meta-entity) defined in 2012, whose pathogenesis depends on monoclonal immunoglobulins (Ig) secreted by ...low-grade lymphoproliferative disorders, which belong to M-protein-related diseases. Renal damage is the result of monoclonal Ig deposit or its activity as autoantibodies, which can compromise any nephronal area. MGRS does not include kidney diseases produced by high-grade lymphoproliferative disorders as well as those whose pathogenesis are independent of monoclonal Ig (such as drug toxicity or metabolic disorders). The importance of this hemato-nephrological meta-entity is based on two aspects: First, it is associated with increased morbidity and mortality, including recurrence in post-renal transplant or its appearance as “de novo” after it; and second, it usually improves after treating the plasmocyte or lymphocyte clone responsible, leading to the elimination of M-protein. Between low-grade lymphoproliferative disorders, monoclonal gammopathy of undetermined significance (MGUS) requires special consideration for two reasons: First, it is the disorder most related to MGRS; second, when MGUS progresses to MGRS, effective treatment against toxic underline clone should be performed taking into account the nephrological perspective.
Crosstalk between the lung and the kidney is based on the similarities that these organs share. This is why different diseases that affect one organ can have repercussions on the other. Patients with ...acute kidney injury can present complications such as pulmonary edema and require mechanical ventilation in respiratory failure. This interaction occurs due to the increase in systemic immune mediators that cause inflammatory reactions, oxidative stress, and an increase in vascular permeability in the lung. With regard to lung-induced renal damage, the kidney can also be affected by chemical mediators, which are translocated into the bloodstream. Moreover, the kidneys are extremely sensitive to oxygen changes which can cause them to lose their autoregulation mechanism. In patients with acute lung injury (ALI), oxygen supply is decreased causing renal hypoxia. Besides, hypercapnia generated by ALI causes vasoconstriction in the renal vascular network and activation of the renal angiotensin aldosterone system. ALI not only can cause renal injury, but also worsening chronic obstructive pulmonary disease and obstructive sleep apnea. In conclusion, kidney–lung crosstalk is commonly present in certain pathological states, and knowing its characteristics is crucial for managing the complications which may arise from this vicious circle.
Frailty is a construct originally coined by gerontologists to describe cumulative declines across multiple physiological systems that occur with aging and lead individuals to a state of diminished ...physiological reserve and increased vulnerability to stressors. Fried et al. provided a standardized definition for frailty, and they created the concept of
frailty phenotype
which incorporates disturbances across interrelated domains (shrinking, weakness, poor endurance and energy, slowness, and low physical activity level) to indentify old people who are at risk of disability, falls, institutionalization, hospitalization, and premature death. Some authors consider the presence of lean mass reduction (sarcopenia) as part of the frailty phenotype. The frailty status has been documented in 7 % of elderly population and 14 % of not requiring dialysis CKD adult patients. Sarcopenia increases progressively along with loss of renal function in CKD patients and is high in dialysis population. It has been documented that prevalence of frailty in hemodialysis adult patients is around 42 % (35 % in young and 50 % in elderly), having a 2.60-fold higher risk of mortality and 1.43-fold higher number of hospitalization, independent of age, comorbidity, and disability. The Clinical Frailty Scale is the simplest and clinically useful and validated tool for doing a frailty phenotype, while the diagnosis of sarcopenia is based on muscle mass assessment by body imaging techniques, bioimpedance analysis, and muscle strength evaluated with a handheld dynamometer. Frailty treatment can be based on different strategies, such as exercise, nutritional interventions, drugs, vitamins, and antioxidant agents. Finally, palliative care is a very important alternative for very frail and sick patients. In conclusion, since the diagnosis and treatment of frailty and sarcopenia is crucial in geriatrics and all CKD patients, it would be very important to incorporate these evaluations in pre-dialysis, peritoneal dialysis, hemodialysis, and kidney transplant patients in order to detect and consequently treat the frailty phenotype in these groups.
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