LECTURE NO. 3 NEPHROTIC SYNDROME DR:BAKIR R.R.
DEFINITION • Definition: nephrotic syndrome is a disorder characterized by heavy proteinuria with hypoprpteinimia ,hyper lipidemia and edema. • It is a primarily pediatric disorder and (15) times more common in children than in adult. • Nephrotic syndrome is not a single disease entity, it may accompany any glomerular disease or injury.
Etiology Idiopathic nephrotic syndrome: this is the most common type , 90% of children has this type of nephrotic syndrome. Secondary nephrotic syndrome: nephrotic syndrome occurs as feature of many diseases like: 1-Glomerular disease: -Membranous nephropathy. -Membranoproliferative glomerulonephritis. -Post infectious glomerulonephritis. -lupus nephritis. -Henoch-schonleinpurpura 2-Secondary to infectious diseases like malaria,schistosomiasis,HBV,HCV,HIV. 3-Secondary to malignancy, particularly in the adult population like carcinoma of the lung, carcinoma of the GIT,lymphoma. 4-Drugs like captopril,NSAID,pencillamine,mercury,lithium,phenytoin. Congenital nephrotic syndrome: Infants who develop nephrotic syndrome in the first three months of life regarded as having congenital nephrotic syndrome. The most common is Finnish type.
PATHOPHYSIOLOGY -The underling abnormality in nephrotic syndrome is increase in permeability of the glomerular capillary wall, which leads to massive proteinuria and hypoalbuminemia. -The mechanism of edema is incompletely understood, it is due to: 1- in most instances, massive urinary loss of protein leads to decreased plasma oncotic pressure and transudation of fluid from the intra vascular compartment to the interistial space. 2-hypovolumia leads to renal hypo perfusion with activation of renin-angiotensin-aldosteron system ,which stimulates tubular reabsorption of albumin. 3-The reduced intravascular volume also stimulates the release of antidiuretic hormone which enhances the reabsorption of water in the collecting duct.
-In the nephrotic syndrome serum lipid levels are elevated for two reasons: 1-hypoalbuminemia stimulates generalized hepatic protein synthesis including synthesis of lipoprotein. 2-lipid catabolism is diminishid,as a result of reduced plasma level of lipoprotein lipase.
IDIOPATHIC NEPHROTIC SYNDROME This is the commonest type of nephrotic syndrome in the pediatric age group ,makes 90% of all cases. It is of three histological types: 1-Minimal change (MCNS) : 85% of total NS. The light microscopy appear normal or show minimal increase in mesangeal cells and matrix. Immunofluorescence is negative, and electron microscopy reveal effacement of epithelial cell foot processes. More than 95% respond to corticosteroid therapy. 2-Mesangeal proliferative: constitute about 5%, characterized by diffuse increase in mesangeal cells and matrix. Approximately 50% are steroid responsive. 3-Focal segmental glomerulosclerosis:constitute 10%, the glomeruli show segmental scarring. Only 20% respond to steroids, and/or cytotoxic drugs. The disease is frequently progressive, ultimately involving all glomeruli and leads to end stage renal disease inmost patients.
CLINICAL MANIFISTATION Clinical manifestations: -More common in male the ratio 2:1. -Most commonly appear between the ages of 2 and 6 years , but has been reported as early as 6 months of age and throughout the adulthood. -The initial episode and subsequent relapses may follow minor infections and, occasionally reactions to insect bites, bee stings. -Children usually presents with mild edema starting in the face, gradually increase to involve the abdomen, scrotum, and lower limbs eventually resulting in ascites, and even pleural effusion -Anorexia,irritability,abdominal pain, and diarrhea are common. -Blood pressure is usually normal, although there may be oliguria.
DIAGNOSIS -Urinalysis reveals 3+ or 4+ proteinuria, microscopic hematuria may present in 20% of children. -Spot urine protein/creatinine ratio exceeds 2. -Urinary protein excretion exceeds 3.5g/24hr in adult and 40mg/m2/hr in children. -The serum albumin level is generally < 2.5g/dl. -The serum cholesterol and triglyceride level are elevated. -C3 and C4 levels are normal. -The serum creatinine level is usually normal , but it may be elevated because of diminished renal perfusion resulting from contraction of intravascular volume. -Renal biopsy is not required for diagnosis in most children.
DIAGNOSIS CONT. Indication of Renal Biopsy: 1. Age <1 year> 8year. 2. Hypertension. 3. Raised s. creatinine. 4. Low C3 serum level. 5. Persistent microscopic or gross hematuria. 6. No response to 6-8 weeks daily divided dose of steroid therapy.
TREATMENT -Children having the first episode and mild to moderate edema may be managed as outpatients. -Affected children may attend school and participate in physical activities as tolerated. -The disease should be reviewed carefully with the family to enhance their understanding of their child's disease . -Sodium intake should be reduced by initiation of a low sodium diet. -Diuretics
TREATMENT CONT. Indications for Hospital Admission: Admitting all patients with new-onset nephrotic syndrome to the hospital is not necessary. Individually address the decision on whether to admit the child or to investigate and initiate treatment on an outpatient basis. •Anasarca, especially when resistant to outpatient therapy and/or accompanied by respiratory compromise, massive ascites or scrotal/perineal or penile edema •Significant hypertension •Anuria or severe oliguria •Peritonitis, sepsis, or other severe infection •Significant respiratory infection •Significant azotemia Hospital admission may be necessary because of social reasons and often is useful on initial presentation of idiopathic nephrotic syndrome (INS) in order to provide intensive education of the family regarding INS and long-term management at home.
TREATMENT Relief of edema: 1. salt restriction. 2. Fluid intakerestriction. 3. mild diuresis. 4. Dietary protein. -In patient with anasarca and sever hypoprotenemia albumin can be giving with close monitoring because there is risk of volume overload and heart failure.
STEROID: is the main line of treatment.Prednisolon in dose of 60mg/m2/ day divided into 3 or 4 doses (it can be giving in a single daily dose ). The average time needed for response is about two weeks. After the initial 6 weeks course, prednisolone is tapered to 40mg/m2/day given every other day as a single morning dose. The alternate day dose is then slowly tapered and discontinued over the next 2-3 months.
Problems that we may face during the management of nephrotic syndrome: -Steroid dependent: there is response while on heavy dose steroid, but on alternating day steroid or within 28 days of stopping steroid there is relapse. -Frequent relapse: more than 4 relapses within one year. -Steroid resistant: when there is no response to 8 wks high dose steroid. -Severe side effects of steroid. They are candidates for alternative agents like: -Cyclophosphamide. -High dose pulse methyl prednisolone -Cyclosporine. -Angiotensin converting enzyme inhibitors and angiotensin II blockers may be helpful as adjunct therapy to reduce proteinuria in steroid-resistant cases.
Investigational Treatments: The following treatments have been studied in nephrotic syndrome, but cannot be routinely recommended: •Rituximab •Plasmapheresis •Galactose •Zinc .Levamisole
Vaccination: Yearly influenza vaccination is recommended to prevent serious illness in the immunocompromised patient, as well as to prevent this possible trigger of relapse. Pneumococcal vaccination should be administered to all patients with INS upon presentation. Vaccination should be repeated every 5 years while the patient continues to have relapses.
Routine childhood vaccines with live virus strains are contraindicated during steroid therapy and for a minimum of 1 month afterward. Care must be taken in administering live viral vaccines to children in remission from FRNS, who might need to restart steroid therapy shortly after vaccination. Routine nonliveviral vaccines should be administered according to their recommended schedules. Despite the former belief that routine immunization can trigger relapse of nephrotic syndrome, no solid evidence supports this, and the risk of these preventable childhood illnesses exceeds the theoretical, unproven risk for triggering relapses.
-Because of the high risk of varicella infection in the immunocompromised patient, post exposure prophylaxis with varicella-zoster immune globulin is recommended in the nonimmune patient. Patient with varicella-zoster infection should be treated with acyclovir and carefully monitored. Varicella immunization is safe and effective in patients with INS who are in remission and off steroid treatment (with the usual precautions for administering live viral vaccines to patients who have received steroids).
COMPLICATIONS 1- Infection. Peritonitis is the most frequent type of infection, but Pneumonia, Cellulitis, urinary tract infection and sepsis are also encountered. The most common type of bacteria that cause infection is streptococcus pneumoni. 2-Increased tendency to arterial and venous thrombosis. 3-Side effects of prolonged steroid therapy. 4-Hyperlipidemia. 5-Renal failure.
Patient with nephrotic syndrome is at increased risk of infection because of : 1-loss of protein through urine including immunoglobulin ,and proper din factor B . 2-defective cell mediated immunity. 3-use of steroid and cytotoxic drugs. 4- malnutrition. 5-oedema and ascites. 6- hypo perfusion of spleen.
PROGNOSIS -The majority of children with steroid –responsive nephrotic syndrome have repeated relapses, which generally decrease in frequency as the child grow older. -Those who response to steroid rapidly ,and have no relapses during the first six months after the diagnosis are likely to follow an infrequent relapsing course. -Those with steroid resistant nephrotic syndrome have a much poorer prognosis.