儿科学教学课件：nephrotic syndrome1

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1、nephrotic syndrome Approximately 90%of children with nephrotic syndrome have idiopathic nephrotic syndrome.The remaining 10%of children with nephrotic syndrome have secondary nephrotic syndrome related to systemic or glomerular diseases.systemic diseases such as systemic lupus erythematosus,Henoch-S

2、chnlein purpura,malignancy(lymphoma and leukemia),and infections(hepatitis,HIV)A number of hereditary proteinuria syndromes are caused by mutations in genes that encode critical protein components of the glomerular filtration apparatus PathologyMinimal change nephrotic syndrome(85%)Mesangial prolife

3、ration(5%)Focal segmental glomerulosclerosis(10%)These 3 disorders may represent 3 separate diseases with a similar clinical presentation;alternately,these disorders may represent a spectrum of a single disease.Clinical manifestationEdema Foamy urineAbdominal painDiarrhea.ascites,pleural effusions,a

4、nd genital edema.hypertension and gross hematuria are uncommon.The idiopathic nephrotic syndrome is more common in boys than in girls(2:1)and most commonly appears between the ages of 2 and 6 yrThe initial episode of idiopathic nephrotic syndrome,as well as subsequent relapses,usually follows minor

5、infections and,uncommonly,reactions to insect bites,bee stings,or poison ivy.The differential diagnosis of the child with marked edema includes protein-losing enteropathy,hepatic failure,heart failure,acute or chronic glomerulonephritis,and protein malnutrition.DiagnosisUrinalysis:proteinuriaSpot ur

6、ine protein/creatinine ratioUrinary protein excretionSerum albuminSerum cholesterol and triglyceride The urinalysis reveals 3+or 4+proteinuria Spot urine protein/creatinine ratio exceeds 2.0 urinary protein excretion exceeds 3.5 g/24 hr in adults and 40 mg/m2/hr in childrenThe serum albumin level is

7、 generally 2.5 g/dL,and the serum cholesterol and triglyceride levels are elevated.TreatmentSodium restriction and fluid restriction Sodium intake should be reduced by the initiation of a low-sodium diet and may be normalized when the child enters remission.oral diuretics are used by many clinicians

8、 for children with nephrotic syndrome.Because of the possibility of increasing the risk of thromboembolic complications,diuretic use should be reserved for patients with severe symptoms and must be closely monitored.IV administration of 25%human albumin(0.5 g/kg/dose q 612 hr administered over 12 hr

9、)followed by furosemide(12 mg/kg/dose IV)is often necessary when fluid restriction and parenteral diuretics are not effective.Children with onset of nephrotic syndrome between 1 and 8 yr of age are likely to have steroid-responsive MCNS;steroid therapy may be initiated without diagnostic renal biops

10、y.Children with features that make MCNS less likely(hematuria,hypertension,renal insufficiency,hypocomplementemia,age 8 yr)should be considered for renal biopsy before treatment.In children with presumed MCNS,prednisone should be administered(after confirming a negative PPD test)at a dose of 60 mg/m

11、2/day(maximum daily dose,80 mg divided into 23 doses)for at least 4 consecutive weeks.After the initial 6-wk course,the prednisone dose should be tapered to 40 mg/m2/day given every other day as a single morning dose.The alternate-day dose is then slowly tapered and discontinued over the next 23 mo.

12、Many children with nephrotic syndrome experience at least 1 relapse(3-4+proteinuria plus edema).Although relapse rates of 60-80%have been noted in the past,the relapse rate in children treated with longer initial steroid courses may be as low as 30-40%.Relapses should be treated with 60 mg/m 2/day(8

13、0 mg daily max)in a single am dose until the child enters remission(urine trace or negative for protein for 3 consecutive days).The prednisone dose is then changed to alternate-day dosing as noted with initial therapy,and gradually tapered over 4-8 wk.A subset of patients will relapse while on alter

14、nate-day steroid therapy or within 28 days of stopping prednisone therapy.Such patients are termed steroid dependent.Patients who respond well to prednisone therapy but relapse 4 times in a 12-mo period are termed frequent relapsers.children who fail to respond to prednisone therapy within 8 wk are

15、termed steroid resistant.Steroid-resistant nephrotic syndrome is usually FSGS(80%),MCNS(20%),and rarely mesangial proliferative.Steroid-dependent patients,frequent relapsers,and steroid-resistant patients are candidates for alternative therapies,particularly if the child has severe corticosteroid to

16、xicity (cushingoid appearance,hypertension,cataracts,and/or growth failure).Cyclophosphamide high-dose pulse methylprednisolone.Cyclosporine tacrolimus Mycophenolate Angiotensin-converting enzyme (ACE)inhibitors and angiotensin II blockers may be helpful as adjunct therapy to reduce proteinuria in s

17、teroid-resistant patients.COMPLICATIONS Infection is the major complication of nephrotic syndrome.Spontaneous bacterial peritonitis Children with nephrotic syndrome are also at increased risk of thromboembolic events.The incidence of this complication in children is 2-5%,which represents a much lowe

18、r risk than that of adults with nephrotic syndrome.To minimize the risk of thromboembolic complications,aggressive use of diuretics and the use of indwelling catheters should be avoided if possible.Hyperlipidemia,particularly in patients with complicated nephrotic syndrome,may be a risk factor for c

19、ardiovascular disease.PROGNOSIS The majority of children with steroid-responsive nephrotic syndrome have repeated relapses,which generally decrease in frequency as the child grows older.Children with steroid-resistant nephrotic syndrome,most often caused by FSGS,generally have a much poorer prognosis.These children develop progressive renal insufficiency,ultimately leading to end-stage renal disease requiring dialysis or kidney transplantation.Recurrent nephrotic syndrome develops in 30-50%of transplant recipients with FSGS.