Management of patients with nephrotic syndrome
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Review article S W I S S M E D W K LY 2 0 0 9 ; 1 3 9 ( 2 9 – 3 0 ) : 4 1 6 – 4 2 2 · w w w . s m w . c h 416 Peer reviewed article Management of patients with nephrotic syndrome Sophie de Seigneux, Pierre-Yves Martin Service de Néphrologie, Département de Médecine Interne, HUG, Switzerland Summary Nephrotic syndrome is characterised by pro- Urinary protein loss leads to several compli- teinuria >3.5 g/24h, oedema, hypoalbuminaemia cations: water and sodium retention, hyperlipid- and hyperlipidaemia. aemia, increased risk of thromboembolism and Several glomerular diseases, either primary or infection, anaemia and alteration of mineral me- secondary, may lead to nephrotic syndrome. In- tabolism. Each of these complications must be vestigations for nephrotic syndrome include im- identified and their treatment is discussed in this munological and infectious evaluations. Renal review. biopsy is often mandatory, except in diabetes. De- pending on aetiology specific treatment, often Key words: nephrotic syndrome; proteinuria; kid- with immunosuppressive agents, may be imple- ney; oedema; hypertension mented. In any cases nonspecific treatment should be started with ACE inhibitors or ARBs. Introduction and definition Nephrotic syndrome is defined by the associ- The aetiological causes of nephrotic syndrome ation of a proteinuria higher than 3.5 g/24 hours, are however miscellaneous, ranging from primary hypoalbuminaemia, oedema and dyslipidaemia. renal diseases to systemic illnesses with various The prevalence of this syndrome is high, histopathological presentations (tables 1 and 2). mainly due to its frequency in diabetic patients. The renal disease revealed by nephrotic syn- drome must be precisely characterised, since al- Table 1 Primary glomerular diseases (frequent; rare) though many therapeutic strategies are common Primary glomerular to all nephrotic patients, specific treatments exist Membranous glomerulopathy diseases associated and must be evaluated in each case. with nephrotic Focal and segmental glomerulosclerosis Independently of the underlying disease, uri- syndrome. Minimal change disease (MCD) glomerulopathy nary protein loss may lead to several complica- IgA nephropathy tions due either to the toxicity of proteinuria on Membranopoliferative glomerulonephritis the kidney, or to plasma depletion of specific pro- C1q glomerulopathy teins. The purpose of this review is to make rec- ommendations for the evaluation of the nephrotic Fibrillar glomerulopathy syndrome and the implementation of nonspecific Congenital podocyte anomaly treatment for nephrotic patients. Aetiology and investigations Nephrotic proteinuria, mainly albuminuria, of these elements, resulting in leakage of albumin involves a glomerular lesion since tubular lesions from the vascular to the tubular compartment. alone will not result in heavy albuminuria. In- Nephrotic syndrome may result from either creased glomerular permeability may occur when primary glomerular or systemic disease leading to No conflict a lesion is present, either in the endothelium, renal insult (tables 1 and 2). Aetiologies of of interest. podocytes, basement membrane or a combination nephrotic syndrome vary depending on the pa- S W I S S M E D W K LY 2 0 0 9 ; 1 3 9 ( 2 9 – 3 0 ) : 4 1 6 – 4 2 2 · w w w . s m w . ch 417 Table 2 Medications (non exhaustive) Allergens, immunisations Causes of secondary NSAIDs, pamidronate, rifampicin, IFN alpha, gold, lithium, Pollens, seric illness, vaccines, bee sting nephrotic syndrome interferon alpha (most frequent). Infections Systemic illnesses (most frequent) Bacterial: Endocarditis, syphilis, tuberculosis, mycoplasma infections Systemic lupus erythematosus (SLE), Viral: HIV, HBV, HCV, EBV, CMV, VZV Rheumatoid polyarthritis, Protozoal: Toxoplasmosis, malaria Schonlein-Henoch purpura Helminthic: Schisostomiasis, trypanosomiasis, filariasis MGUS, amyloidosis Neoplasia Metabolic diseases and heredofamilial (non exhaustive) Solid tumours Type I and II diabetes Haemo- or lymphopathies Hypothyroidism Multiple myeloma Alport syndrome GVHD post marrow transplantation Graves disease Fabry disease Miscellanous (examples) Pregnancy-associated Chronic allograft failure Nephronic reduction Renal artery stenosis Obesity Heart failure (right/left) and pericarditis tient’s age. Among secondary causes, type I or II phonates, NSAIDs, heavy metals etc). Nephrotic diabetes remain the most frequent aetiology in syndrome patients require a thorough workup adults, although approximately 10% of nephrotic and our recommended initial evaluation of syndrome cases in diabetes are due to other renal nephrotic patients is summarised in table 3. Eval- diseases. Other systemic diseases, such as systemic uation of proteinuria can be done by 24-hour col- lupus erythematosus (SLE), amyloidosis, hepatitis lections initially and then followed by iterative B and C, HIV, neoplasms or haematologic dis- measurement of the protein-on-creatinine ratio. eases may also be associated with glomerular dis- This ratio relies on the fact that adults excrete on orders causing nephrotic syndrome. Finally, drugs average 1 g creatinine per day. It can safely be or toxic substances must be considered (bisphos- used to monitor the evolution of proteinuria and is a good renal prognosis factor . Table 3 Complete medical Blood tests Renal biopsy plays a major role in the evalua- history Initial evaluation of Blood count, electrolytes ( CRP, Na, K, tion of nephrotic patients, since several histologi- nephrotic patients BUN, creatinine, albumin, serum proteins, (except diabetes). cal lesions are associated with nephrotic syn- calcium, phosphate, bicarbonates, chloride) Urinary spot and sediment drome. Diabetic glomerulosclerosis, membranous glomerulopathy, focal segmental glomeruloscle- 24-hour proteinuria and/or protein/ creatinine ratio rosis and minimal change glomerulopathy are the most common in adults. The three latter may be Serum and urinary electrophoresis and immuno-electrophoresis either primary or a component of a systemic dis- Lipid profile ease. The sharing and variability of clinical mani- festations among these different glomerular dis- Liver tests eases do not allow accurate diagnosis based on HBV, HCV, HIV serology clinical and laboratory features alone. Renal Immunological profile ( ANA, RF) biopsy is therefore mandatory for every nephrotic glycaemia patient except the diabetic patient, in order to de- TSH fine the disorder accurately and optimise treat- Coagulation tests ment. In diabetic patients atypical features such as a rapidly progressive nephrotic syndrome or acute Complete physical Additional tests examination renal failure, presence of glomerular haematuria Renal duplex echography and/or absence of associated microvascular le- ECG et chest x-ray sions (retinopathy, neuropathy) are indications for Renal biopsy renal biopsy. Prognosis Vital prognosis is mainly influenced by the Renal prognosis is dependent on non-modifi- disorder causing nephrotic syndrome. However, able variables such as the cause of nephrotic syn- nephrotic proteinuria confers per se a higher car- drome, renal function and age at presentation, as diovascular risk, and nephrotic patients are at risk well as the extent of renal interstitial lesions on of several systemic complications to be detailed the biopsy. Prognostic factors are not similar for later. all nephrotic syndromes. A well studied example is Management of patients with nephrotic syndrome 418 membranous nephropathy, where the best param- complete elimination of proteinuria results in eters for predicting the evolution of renal func- renal function preservation, in diabetic or non-di- tion are creatinine clearance at diagnosis, the ex- abetic patients .The magnitude of proteinuria tent of proteinuria (< or >4 g/day) and the slope of and its correction is therefore a major modifiable creatinine clearance over a six months’ observa- risk factor for progression to end-stage renal fail- tion period. Partial or complete remission of pro- ure. The main therapeutic goal in nephrotic pa- teinuria at six months accurately predicts the risk tients is to reduce proteinuria to the lowest possi- of progression in this disease [2, 3]. Several stud- ble level. ies have also demonstrated that either partial or Specific treatments In diabetes, metabolic control is the mainstay three diseases. Immunosuppressive or im- of treatment. In other secondary causes of munomodulatory drugs are therefore the main- nephrotic syndrome specific treatment varies de- stay of treatment, therapeutic strategies depend- pending on the causative illness, e.g. curative or ing on the clinical and histological features. The palliative treatment of a neoplastic disease, antivi- decision to treat and how to treat the patients can- ral treatment of hepatitis or immunosuppressive not be detailed here and many options are possi- therapy of a systemic disease. ble. Several regimens which generally include cor- Among primary renal diseases the most fre- ticosteroids have been studied and are not detailed quently encountered are membranous glomeru- here. However, irrespective of these specific treat- lopathy, focal segmental glomerulosclerosis and ments, nonspecific protective therapies must be minimal change glomerulopathy. An underlying implemented in patients with nephrotic syn- immunological disorder is suspected in these drome. Nonspecific treatments of proteinuria These treatments are therefore either comple- of glomerular lesions leading to proteinuria. RAA mentary to a specific treatment or the sole therapy system blockade has been shown to be successful in available to lower proteinuria. In contrast to spe- reducing proteinuria in both animal and human cific treatment, complete remission of proteinuria studies.ACE inhibitors and ARBs are therefore rec- cannot be expected with these treatments. A rea- ommended as first line treatment in proteinuric sonable goal is to aim at a 50% reduction in pro- diseases, even in the absence of hypertension.Their teinuria, or, even better, at proteinuria below antiproteinuric effect relies on the decrease in 1g/day, which seems to be a critical threshold for glomerular pressure due to their preferential va- long term renal survival. sodilatory effect on the glomerular efferent arteri- ola, rather than on their antihypertensive effect per Antihypertensive treatment se. There is also experimental evidence of a direct Tight blood pressure control is critical to renal protective effect of these drugs on the glomerular function preservation in all cases of proteinuric re- filtration barrier . nal diseases, aiming at upper systolic and diastolic Both drugs have exhibited their nephroprotec- values of 125 and 75 mm Hg respectively. It should tive action in either type I (ACE inhibitors) or type also be mentioned that low blood pressure likewise II (ARB) diabetes or in the nondiabetic population appears to be detrimental and lowering blood pres- [6–9].This favourable effect on renal survival is well sure below 110 mm Hg systolic should be avoided correlated to the extent of proteinuria reduction .All classes of antihypertensive drugs can be used . to meet these targets, and a combination of 2–4 dif- Introduction of ACE inhibitors or ARBs may ferent drugs is often necessary. 24-hour ambulatory be risky in nephrotic patients, in particular when re- blood pressure measurement is often needed to as- nal dysfunction is present. Plasma creatinine often sess optimal control and optimise treatment. Asso- rises after treatment initiation and a 30% increase ciation of a low salt diet (6 g/day) is mandatory to should be tolerated. If plasma creatinine rises more optimise the action of antihypertensive drugs. than 30% transient interruption of the treatment is recommended and a search for a precipitating con- Angiotensin conversion enzyme (ACE) dition such as renal artery stenosis or relative hy- inhibitors and angiotensin type 1 receptor povolaemia (diuretics, severe hypoalbuminaemia antagonists (ARBs) <20 g/L) should be conducted. It should be borne Stimulation of the renin-angiotensin- in mind that proteinuria per se stimulates tubular aldosterone (RAA) system is critical to the genesis creatinine secretion and therefore induces overes- S W I S S M E D W K LY 2 0 0 9 ; 1 3 9 ( 2 9 – 3 0 ) : 4 1 6 – 4 2 2 · w w w . s m w . ch 419 timation of renal function. Proteinuria correction secondary to a systemic or primary glomerular dis- will therefore decrease this secretion and increase ease, the therapeutic strategy may differ, a recent plasma creatinine levels without actually altering meta-analysis having shown that dual RAA block- renal function. ade was safe and had an additional antiproteinuric Hyperkalaemia may also be a limiting factor. effect despite a tendency to increase plasma potas- Plasma potassium up to 5.5 mmol/L is tolerated. sium levels . The dual blockade can therefore Above this level, ACE inhibitors or ARB should be recommended if proteinuria persists despite a be decreased in dosage or even stopped. Impor- maximum dose of either ACE inhibitors or ARB, tantly, concomitant medications, such as beta conditional on careful renal and electrolyte moni- blockers, spironolactone, potassium sparing di- toring. uretics and cyclosporine may potentiate a rise in plasma potassium level. Diuretics When starting a patient on ACE inhibitors or Diuretics are an integral part of the treatment ARBs, serum creatinine and potassium levels must of nephrotic syndrome, given the presence of be checked with a second blood test within five oedema. In addition to their effect on oedema, dis- days after the start of the treatment and after each cussed later in more detail, diuretics are also criti- dose modification. Once stable, monthly blood cal for blood pressure control, potentiating the ef- testing is recommended in nephrotic patients. fect of either ACE inhibitors or ARBs. This syner- Finally, if clinical and biological tolerance of gistic effect is also observed on proteinuria reduc- the medication is good, dosage should be in- tion. creased to the maximum recommended level to maximise the antiproteinuric effect. Small studies Aldosterone antagonists have demonstrated that supramaximal doses of Spironolactone is a mineralocorticoid receptor ARBs (e.g. irbesartan 900 mg) could further re- antagonist which possesses a diuretic effect, partic- duce proteinuria. We recommend however tar- ularly in cases or primary or secondary stimulation geting only maximum doses, except in very lim- of the RAA system. It also has potential antipro- ited situations. teinuric effects, small studies having demonstrated In the event of persistent heavy proteinuria that addition of spironolactone to either ACE in- despite maximal doses of either one treatment hibitors, ARBs or both in nondiabetic proteinuric (ACE inhibitors or ARBs), dual blockade of the patients may have an additive effect on proteinuria RAA system may be useful. reduction. In diabetic patients similar results are Recently, however, the “On Target” trial  observed with the association of spironolactone to has raised issues regarding the validity of this as- maximum doses of either an ACE inhibitor or an sociation. This multicentric study comparing ARB .These studies, however, were short-term three groups of high risk cardiovascular patients and not designed to assess preservation of renal (a group treated with ACE, a group treated with function. ARB or a combination of ACE and ARB) failed to The triple association (ACE,ARB and spirono- demonstrate a beneficial role of the combination lactone) can therefore be considered in specific pa- with respect to survival and hard renal endpoints, tients with refractory proteinuria despite optimal such as renal failure progression and beginning of ACE and ARB treatment. The risks of hyper- dialysis, despite an additive effect on proteinuria kalaemia well documented with spironolactone reduction. The association even appeared delete- must be carefully considered . Eplerenone, an- rious in some patients, with an increased rate of other mineralocorticoid receptor antagonist, can hypotensive episodes, hyperkalaemia and acute be regarded as equivalent to spironolactone al- renal dialyses. though not yet accepted in this indication. Before citing additional information on more detailed analyses of subgroups of patients from Direct renin inhibitors this large study (25 000 patients), we need to inte- Aliskiren, a direct renin inhibitor, is now com- grate these results into our practice. In a patient mercially available in Switzerland. This drug di- aged over 55 with diabetes and/or vascular prob- rectly inhibits the enzymatic activity of renin. A re- lems and nephrotic syndrome, the aim will be to cent study showed that addition of aliskiren to an normalise blood pressure and reduce proteinuria. ARB in diabetic proteinuric patients was beneficial Either an ACE inhibitor or an ARB will then be in reducing albuminuria . These results are in- chosen and the dosage adjusted according to clin- teresting, but the short follow-up (six months) and ical and biological tolerability. Other antihyper- the specific type of population studied require ad- tensive drugs may be added to achieve optimum ditional studies to define the exact place of this new blood pressure control. The combination of ACE class of drugs compared toACE inhibitors andARB inhibitors and ARB is not recommended in this in nephrotic patients. case. There are no data regarding the triple associ- In a young (<55 years old) or older patient with ation of ACE inhibitors, ARBs and aliskiren, no increased cardiovascular risk (no hypertension, and hence this combination cannot be recom- no diabetes), presenting with nephrotic syndrome mended. Management of patients with nephrotic syndrome 420 NSAIDs Dietary factors Non-steroidal anti-inflammatory drugs Sodium intake should imperatively be reduced (NSAIDs) reportedly decrease proteinuria . to less than 6 g/day in order to minimise oedema This effect is essentially mediated by a decrease in and hypertension, and to potentiate the effect of glomerular filtration rate consecutive to inhibition ACE inhibitors and ARBs. of vasodilatory prostaglandins and the treatment is Protein intake has been a subject of debate in restricted to very limited cases of symptomatic nephrotic syndrome. Various studies have demon- nephrotic syndrome refractory to other classical strated that a high protein diet (to correct for the treatments. In these cases iatrogenic reduction of urinary losses) was ineffective in correcting hy- glomerular filtration rate may play a beneficial poalbuminaemia . Moreover, the increased symptomatic role. protein intake tends to further increase proteinuria and glomerular hyperfiltration, and is therefore Calcium channel blockers probably deleterious. Conversely, low protein diets Calcium channels blockers are potent antihy- (<0.8 g/kg/d) have a slight anti-proteinuric effect pertensive drugs. They are therefore useful in which might be valuable . Vegetable proteins meeting blood pressure targets and hence may con- appear to be beneficial compared to animal pro- tribute to decreasing proteinuria. This is observed teins in reducing proteinuria. However, muscle with both verapamil, diltiazem or dihydropiridine wasting being a major problem in nephrotic pa- calcium channel blockers. The latter may have a tients, and a low protein intake diet increasing the synergistic vasodilatory effect with ACE inhibitors risk of malnutrition, it is not recommended. or ARB on the efferent artery, and may have car- In practice we recommend a protein intake of dioprotective effects . 0.8–1 g/kg/d, with a preference for vegetable and These drugs are therefore useful in nephrotic fish proteins. Intravenous supplementation of al- syndrome, their major drawback being the occur- bumin is not beneficial and is not recommended, rence or aggravation of peripheral oedema. except in cases of very severe hypovolaemia. A nutritionist consultation is recommended to every nephrotic patient. Complications of nephrotic syndrome Oedema blockade of the nephron is habitually needed, the Pathophysiological mechanisms resulting in collecting duct being an interesting target in view water and sodium retention are still a subject of de- of its probable physiopathological role. Mainte- bate. There are two theories in the field. The first nance of a low salt diet is crucial for the effective- is that decreased oncotic pressure and relative hy- ness of antihypertensive drugs and diuretics, to- povolaemia are the triggers for renal water and gether with periods of bed rest (with antithrom- sodium retention due to subsequent activation of botic prophylaxis). In severe cases intravenous ad- the RAA and vasopressin systems. The second the- ministration of loop diuretics may be necessary. In ory is in favour of primary renal dysfunction with the event of profound hypoalbuminaemia (plasma inappropriate sodium retention by the cortical col- levels <15 g), especially in the acute setting and as- lecting duct . Globally, both mechanisms are sociated with hypovolaemia, intravenous desalted probably active at different phases of the disease albumin may be administered. The weight loss and both participate in water and sodium retention should approximate 1 kg per day and both renal in this disease. function and electrolytes must be carefully moni- In children presenting with pure nephrotic tored during diuretic treatment. syndrome without hypertension and with normal renal function, amiloride, an inhibitor of the Lipid metabolism sodium epithelial channel (ENaC) which blocks Dyslipidaemia may be marked, with an in- sodium reabsorption in the collecting duct, is often crease in total cholesterol, LDL, triglycerides and very efficient. lipoprotein (a). In adults, sodium retention is frequently asso- Dyslipidaemia in nephrotic syndrome con- ciated with a decrease in glomerular filtration rate tributes to the increased cardiovascular mortality and hypertension. In this situation diuretics should in these patients, and may also be involved in renal be associated with ACE inhibitors or ARBs. If re- disease progression. Screening and treatment of nal function is relatively preserved, either dyslipidaemia are therefore of critical importance. amiloride or thiazides or spironolactone can be The pathogenesis of dyslipidaemia in chosen as the first alternative.A loop diuretic is usu- nephrotic patients is not yet totally understood. ally necessary to obtain efficient natriuresis. In- Decreased plasma oncotic pressure stimulates he- deed, given the intensity of sodium retention and patic synthesis of different proteins and may con- the diversity of causal mechanisms, a sequential tribute to the increase in LDL.Acquired HDL me- S W I S S M E D W K LY 2 0 0 9 ; 1 3 9 ( 2 9 – 3 0 ) : 4 1 6 – 4 2 2 · w w w . s m w . ch 421 Table 4 Complication Recommendations Summary of Proteinuria Specific treatment according to primary disease recommendations. In all cases: ACE inhibitors or ARBs increased to maximum dose depending on biological and clinical tolerance If age <55 or no comorbidities: evaluate ACE and ARB combination If refractory proteinuria, consider spironolactone Oedema Low salt diet Amiloride in children Sequential diuretic blockade in adults (loop diuretics, thiazide, spironolactone or amiloride) Hyperlipidaemia Lipid profile Statin if pathological or severe long lasting nephrotic syndrome Hypertension ACE inhibitors or ARBs as first choice Thiazides or calcium channel blockers in association Low salt diet Hypoalbuminaemia High protein diet not indicated 0.8–1 g/kg/day Thromboembolic risk Prophylactic anticoagulation if immobilisation Full-dose anticoagulation if thrombotic event or membranous nephropathy and severe hypoalbuminaemia (alb <20 g/l) In other cases of NS: to be discussed depending on bleeding risk Anaemia Anaemia evaluation Erythropoietin if required Target haemoglobin 11–12 g/l Infections High index of suspicion Antipneumococcal and influenza vaccinations Bone metabolism Vitamin D and calcium Bisphosphonates if steroids and/or pathological osteodensitometry ACE: Angiotensin conversion enzyme / ARB: Angiotensin receptor blocker tabolism abnormalities resulting in increased ent. Primary prophylaxis is a much more difficult triglycerides and decreased HDL synthesis have problem . Markov risk benefits analyses have also been observed . demonstrated a higher expected benefit than risk Statins are efficient and safe for the treatment from full dose prophylactic anticoagulation in se- of dyslipidaemia in patients with nephrotic syn- vere membranous-associated nephrotic syndrome drome. Statins reduce cardiovascular risk in mod- (plasma albumin <20 g/l) . This is however not erate renal failure patients  and should be im- applicable to secondary nephropathies such as dia- plemented as long as nephrotic syndrome is ongo- betic nephropathy. ing. Proteinuria reduction is however the best In practice, except for diabetic nephrotic syn- treatment for dyslipidaemia correction. drome, institution of primary prophylaxis by full dose anticoagulation should be discussed accord- Thromboembolism ing to the type of disease, its severity and individ- Nephrotic syndrome is a risk factor for throm- ual haemorrhagic risk, but is usually indicated as boembolic events, mainly in young patients and at long as proteinuria is ongoing and serum albumin the beginning of the nephrotic syndrome. The risk below 20 g/l. can be as high as 40% in particular forms of renal disease such as membranous nephropathy.Throm- Infections boembolic events remain highly suspect in Nephrotic patients present a high risk of in- nephrotic patients. fection. Encapsulated pathogens (e.g pneumococ- The pathophysiology of thromboembolic cus) are frequently encountered in children (pneu- events is related to imbalance between pro- and an- monia, spontaneous peritonitis, dermohypodermi- ticoagulant factors. Urinary loss of antithrombotic tis) and are associated with severe disease. In adults factors (mainly antithrombin III) and synthesis of the bacterial susceptibility extends to gram-nega- procoagulant factors are implicated in the patho- tive rods. This susceptibility is probably related to genesis of this complication. The higher incidence loss of various immunoglobulins and alternate observed in some glomerular disorders (e.g. mem- complement pathway dysfunctions in part due to branous nephropathy), is unexplained. urinary loss. Immunosuppressive treatments fur- Treatment of an incidental thromboembolic ther increase susceptibility to other pathogens such event is similar to a standard event, with the differ- as CMV, PCP, etc., usually if nephrotic syndrome ence that full dose anticoagulation should be main- persists. tained as long as the nephrotic syndrome is pres- Anti-influenza and antipneumococcal vaccina- Management of patients with nephrotic syndrome 422 tion is therefore recommended with plasma mon- the erythropoietin level is low, administration of itoring of antibodies (for pneumococcus) after six erythropoiesis synthesis agents (ESA) is indicated, months, given the high risk of immunity loss. A targeting a haemoglobin level of 11–12 g/l. high degree of suspicion should be entertained re- garding infections in these patients. Bone metabolism Renal failure is associated with secondary hy- Anaemia perparathyroidism and hypovitaminosis D. In Anaemia of chronic renal disease is related to nephrotic patients this may be further complicated inadequate erythropoietin production by the kid- by urinary loss of albumin and globulins that are vi- neys (endocrine failure). In nephrotic patients this tamin D transporters. Monitoring of serum cal- can be aggravated by urinary losses of erythropoi- cium and phosphates as well as vitamin D and PTH etin, transferrin and iron. The association of measurement is warranted in these patients. nephrotic syndrome with anaemia in the absence Steroid treatments will also alter bone density. or renal dysfunction is still a subject of debate . If possible, supplementation with calcium and In cases of anaemia a standard evaluation vitamin D is recommended in all patients. De- should be performed (reticulocytes count, B12, fo- pending on the clinical context and associated med- late, iron status). In the absence of renal dysfunc- ications, mostly corticosteroids, a dual absorption tion and with an unexplained aregenerative densitometry and/or bisphosphonate therapy may anaemia, erythropoietin measurement is useful. If be indicated . Conclusion In conclusion, diagnosis and follow up of Correspondence: nephrotic patients require close cooperation be- Pierre-Yves Martin tween general practitioners and nephrologists to Service de Néphrologie ensure the best possible care. 24, rue Micheli du Crest Evaluation and treatment of complications CH-1211 Genève 14 are crucial in order to minimise mortality and Switzerland morbidity associated with nephrotic syndrome. E-Mail: email@example.com References 1 Ruggenenti P, Gaspari F, Perna A, Remuzzi G. Cross sectional longitudi- 13 Juurlink DN, Mamdani MM, Lee DS, et al. Rates of hyperkalemia after nal study of spot morning urine protein:creatinine ratio, 24 hour urine publication of the Randomized Aldactone Evaluation Study. 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