Clinical Queries: Nephrology最新文献

IgA nephropathy is the commonest primary glomerular disease worldwide. A high prevalence has been noted in Asia including India. The clinical course has a wide spectrum of presentation varies from isolated microscopic hematuria to crescentic glomerulonephritis. The approach of the treatment has to be decided as per the clinical and histopathological manifestation of the disease. Risk assessment is important to determine management and also to balance between the risks of therapy by the selection of patients. Clinical features appear to be the stronger prognostic indicators however certain renal histopathological findings have been associated with an increased risk of progressive disease. There is no definitive therapeutic approach despite of better understanding of pathogenic mechanism of the disease. The expected outcome of therapy is slowing the deterioration in kidney function as well as a reduction in proteinuria and control of blood pressure by suppression of angiotensin II with ACE inhibitors or angiotensin II-receptor blockers (ARBs). The indications for the use of corticosteroid alone or in combination with other immunosuppressive agents e.g. Azathioprine or cyclophosphamide are not well defined. Different regimens have been used, consisting of corticosteroids alone or in combination with other immunosuppressive agents.

Despite retrospective studies in IgA nephropathy supporting the use of immunosuppressive therapy other than corticosteroid, few randomized control trials have demonstrated a benefit. Corticosteroid combined with cyclophosphamide or azathioprine can be considered in patients with rapidly progressive disease with crescentic IgA nephropathy. Fish oil can be used in the treatment of IgA nephropathy with proteinuria above 1 g/day despite 3–6 months of optimized therapy with ACE inhibitors or ARBs and blood pressure control.

Chronic kidney disease (CKD) is emerging health problem with prevalence of approximately 10% in general population. The incidence and prevalence of cardiovascular disease (CVD) is high in CKD patients, approaching >50% in patients in advance CKD. CVD outcomes are worse in presence of CKD suggesting different pathophysiology compared to general population. Patients with CKD are at increased risk of both atherosclerotic and structural heart disease, stroke and peripheral vascular disease. Congestive heart failure is most common cardiac condition. The increased incidence of CVD is attributed to presence of both traditional and kidney specific risk factors. The kidney specific risk factors include albuminuria, inflammation, hyperparathyroidism, altered calcium phosphate metabolism, homocysteine level and recently recognized coronary artery calcification gene. The preventive and therapeutic strategies for CVD applied to general population are also applicable in patients with CKD but with poor outcomes. The understanding of pathophysiology may provide better insight to develop methods with favorable outcomes in this unique patient population.

Cardiorenal syndrome (CRS) is an umbrella term that defines disorders of the heart and kidneys whereby “acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other”. The heart and the kidneys are involved in maintaining hemodynamic stability and organ perfusion through an intricate network. Dysfunction of one organ may lead to dysfunction of the other. CRS was recently sub-classified into 5 types primarily based upon the organ that initiated the insult as well as the acuity and chronicity of disease. Development of CRS is associated with increased morbidity, hospital stay, cost of healthcare and mortality. Newer biomarkers have shown potential for early diagnosis of CRS.

Dysregulation of phosphate homeostasis occurs in chronic kidney disease (CKD). Hyperphosphatemia is an ongoing challenge in treating CKD patients. Restriction of dietary proteins remains one of the cornerstones of nutritional management of CKD patients foods from animal sources are rich in organic phosphorus. Foods sources including certain beverages like colas, enhanced meats, frozen meals, snack bars, processed or spreadable cheeses, instant food products, and refrigerated bakery products are rich in inorganic phosphorus.

Phosphate additives added to foods further increases the phosphorus burden. It is estimated that the intestinal absorption of inorganic phosphorus is usually more than 90% compared to only 40%–60% from that of the organic phosphorus. Phosphates from animal food are more readily absorbed compared to that present in plant foods sources as majority of it is present in the form of phytate and hence not readily absorbed. Intensive nutritional counseling regarding phosphorus content of foods, their bioavailability with an emphasis on consumption of a mixed diet including foods from animal sources and plant sources high in phytate. While limiting or avoiding the intake from foods very high in phosphorus to protein ratio and foods rich in phosphorus additives but with an adequate protein content to avoid malnutrition, reinforcement on dietary compliance and judicious use of phosphorus binders are important for the better management of hyperphosphatemia in CKD. Methods like soaking foods in water and boiling them helps in reducing the dietary phosphorus content per gram of protein in foods.

Hypertension is a leading cause of morbidity and mortality in clinical practice. It may be either a consequence or a cause of CKD. It is a major factor contributing to the kidney disease and to faster decline in GFR. Management of hypertension is a key component in the treatment of CKD, in preventing the progression of CKD and other target organ damage in the schema of hypertension spectrum.

An arteriovenous fistula (AVF) is created by direct anastomosis between an artery and adjacent vein which leads to flow of blood from artery directly into the vein. A well functioning and patent AVF is essential for optimum delivery of hemodialysis and hence it is important to assess the AVF for any signs of loss of patency (stenosis/thrombosis) on a regular basis. Methods of AVF monitoring include physical examination and other features like difficulty in AVF cannulation due to poor blood flow, clot aspiration or prolonged bleeding from the AVF site post hemodialysis. Methods of AVF surveillance include access blood flow, venous pressure and Doppler ultrasound etc. Both physical examination and investigations have complimentary role in this field and it is necessary that adequate stress is given on monitoring on a continuous basis. Access blood flow and intra-access pressures have role in confirming any abnormal physical examination finding.

Antiphospholipid antibody syndrome (APS) is characterized by recurrent pregnancy losses and/or thrombotic events (both arterial and venous) with persistently positive lupus anticoagulant or antiphospholipid antibodies. Activation of complements, platelets and endothelial cells by the anticardiolipin-β2GP-1 complex plays a major role in pathogenesis of thrombosis. Treatment is with anticoagulation (warfarin/heparin), with steroids needed in the presence of catastrophic APS or cytopenias. Upto a third of patients may have significant long term morbidity.

Autonomic symptoms are frequently encountered in chronic renal disease patients, either as a part of distal symmetric polyneuropathy and small fiber sensory polyneuropathy or as primary autonomic polyneuropathy independent of somatic neuropathy. Pathogenesis of latter remains elusive. Sudomotor, gastrointestinal and cardiological involvement is common. Renal replacement therapies are not as efficacious in curing autonomic neuropathy as in somatic polyneuropathy of uremia. A greater awareness of this entity across various disciplines and subsequent multidisciplinary approach involving nephrologists, gastroenterologist and cardiologist, as needed, is probably the best bet at present, to ease the suffering patient.