General Clinical Features And Special Types Of Nephrotic Syndrome
Nephrotic Syndrome Moon Face After Cortisone
A General Overview
The clinical features of the different types of idiopathic nephrotic syndrome are different. The onset is generally insidious with pedal edema and facial puffiness and these lead on to anasarca. Hypertension, microscopic hematuria, oliguria and renal failure are seen only in certain types of nephrotic syndrome. Rarely, patients may present with intravascular hypovolemic states brought on by the loss of fluid due to vomiting, diarrhea, or inappropriate diuretic therapy. Infections are more common in these patients due to loss of immunoglobulins. The examination of urine reveals massive proteinuria and variable degrees of hematuria. Hyaline casts are common but RBC casts are seen only in some types of proliferative GN. Biochemical examination of blood reveals hypoalbuminemia (less than 2g/dl), hypercholesterolemia (above 300 mg/dl), and hyperlipidemia. The serum complement levels are reduced in membrano-proliferative GN but not in the others.
The diagnosis of nephrotic syndrome is established by demonstrating the presence of massive proteinuria in a 24 hour collection of urine. Renal biopsy helps in identifying the type of nephrotic syndrome. Estimation of serum complement, electron microscopy and immunoflourescence microscopy help in establishing the etiology further.
Nephrotic Syndrome In Children
Nephrotic Syndrome Manifestations
Special types of nephrotic syndrome
Minimal change GN: This is more common in children, but may occur at any age. It is characterized by insidious onset of edema. Hypertension, hematuria and symptoms of renal failure are rare. Children with nephrotic syndrome are prone to develop infections, particularly bacterial peritonitis. Hypovolemic shock or acute tubular necrosis may develop in these children following gastroenteritis or inappropriate diuretic therapy. The serum albumin level is markedly reduced and the cholesterol and lipid levels are considerably increased. The blood urea, serum creatinine and complement levels are within normal.
These patients show good response to the administration of corticosteroids. Prednisolone is given in doses of 2mg/Kg body weight for children and 1mg/Kg for adults as a single morning dose daily for 4-6 weeks. The dose is reduced after achieving remission. The long term response to steroid therapy is variable. Some patients go into prolonged and complete remission characterized by the full disappearance of proteinuria and clinical abnormalities. In some, relapse occurs within a few weeks of stopping treatment (frequent relapsers). Some relapse on reducing the dosage of steroids but they respond well to the increase in the dose (steroid-dependent cases). Steroid resistance is encountered rarely. Frequent relapsers, steroid-dependent cases and steroid resistant cases may benefit from a short course of treatment with cyclophosphamide, or chlorambucil, given for 4-8 weeks. The immunosuppressant regimen has to be given in selected cases under supervision with proper monitoring of blood counts.
Membranous glomerulopathy (Membranous GN): It is more common in persons above the age of 40 years. There is a male preponderance. The disease may present as asymptomatic proteinuria or with the classical clinical features of nephrotic syndrome. Microscopic hematuria is common. Hypertension and renal failure occur later in the course of the disease. Membranous glomerulopathy may be idiopathic in some cases. The known causes are systemic lupus erythematosus, diabetes mellitus, drug toxicity and malignant neoplasms. Light microscopy of renal biopsy specimen shows diffuse and uniform thickening of the capillary basement membrane without any significant proliferation of endothelial, mesangial or epithelia cells. In advanced cases, the basement membrane is thickened in an irregular manner to give rise to a ‘mouth-eaten appearance’ detectable on electron microscopy.
The response to corticosteroids and immune-suppressive therapy is variable. However, the severity of proteinuria comes down with aggressive therapy. Some of these patients may go into spontaneous remission lasting for a few months to a few years, subsequently to relapse and progress gradually to renal failure. The incidence of renal vein thrombosis is higher in membranous glomerulopathy. Rapid deterioration of renal function, increase in edema and unresponsiveness to therapy should suggest the possibility of this complication.
Membranoproliferative GN (Mesangiocapillary GN): Membranopriliferative GN is more common in the age group of 5-12 years and there is a slight female preponderance. The onset if relative abrupt with puffiness of the face, oliguria and hematuria, following an acute respiratory infection. This type of onset resembles acute nephritic syndrome. Other forms of presentations are asymptomatic proteinuria, or as nephrotic syndrome. Proteinuria, hematuria and hypertension are commonly present from the early stages. Renal failure and severe hypertensive crisis are also common complications. Serum C3 complement levels are persistently low.
Light microscopy reveals enlargement of the glomerulus and accentuation of the lobular architecture. There is proliferation of the mesangial cells and extensive circumferential extensions of the mesengial cells between the endothelium and basement membrane giving rise to an appearance of splitting of the basement membrane. Polymorphonuclear leukocytes may be seen in the glomerular capillary tuft.
Two types can be identified under electron microscopy. In type I, there are electron dense deposits in the subendothelium and in type II electron dense deposits are in the glomerular basement membrane. Immunofluoresecent microscopy shows deposition of C3 in the glomerulus.
The clinical course is generally one of the progressions. It is rare to achieve remission. Treatment with prednisolone and other immunosuppressive drugs may help in retarding the rate of progress in some cases.
© 2014 Funom Theophilus Makama