Secondary Causes
Congenital infections: syphilis, cytomegalovirus, toxoplasmosis, rubella, human immunodeficiency virus (HIV), malaria, hepatitis B
Immunologic: maternal systemic lupus erythematosus

Diagnosis
An examination reveals massive fluid retention and generalized swelling. Abnormal sounds are heard when listening to the heart and lungs with a stethoscope. Blood pressure may be high. The patient may have signs of malnutrition.A urinalysis reveals large amounts of protein and sometimes small amounts of blood in the urine. Kidney function may be normal in the first weeks or months of life. Laboratory studies show low serum levels of protein (albumin) and immunoglobulins, and elevated levels of triglycerides and cholesterol. Blood work may also show thyroid and vitamin D deficiency. Kidneys on ultrasound imaging may appear enlarged and brighter (hyperechoic). The disorder can be screened during pregnancy by finding elevated levels of alpha-fetoprotein on a routine sampling of amniotic fluid.Indication for kidney biopsy remains unclear as histologic findings do no reveal the cause of congenital nephrotic syndrome, but findings may help in developing treatment strategies. Findings on light microscopy can vary from minimal change nephropathy to focal segmental glomerulosclerosis or diffuse mesanigial sclerosis. Electron microscopy shows podocyte disruption (loss of foot processes or slit diaphragm).Genetic analysis and infectious workup are needed to determine the precise cause of congenital nephrotic syndrome. Understanding the underlying cause can assist in disease management, prognosis, and genetic counseling. Treatment
Genetic forms of nephrotic syndrome are typically resistant to steroid and other immunosuppressive treatment.
Goals of therapy are to control urinary protein loss and swelling, provide good nutrition to allow the child to grow, and prevent complications. Early and aggressive treatment is required to control the disorder. Patients with severe urine protein loss require albumin infusions help replace protein loss and diuretic medications help rid the body of excess fluid. For patients with mild to moderate urine protein losses, ACE inhibitor medications (like Captopril and others) and non-steroidal anti-inflammatory drugs (like indomethacin) are used to slow the spilling of protein (albumin) in the urine. Removal of the kidneys (one at the time or both) can decrease protein loss and limit the number of albumin infusions needed. Infants with WT1 mutations will undergo bilateral kidney removal to prevent development of Wilms tumor.Antibiotics may be needed to control infections. Immunizations are recommended after kidney removal but prior to transplantation. Patients may also take iron supplements, potassium chloride, thyroxine and other vitamins to replenish what minerals the kidneys have leaked out. Anticoagulants (such as aspirin, dipyridamole, and warfarin) are used to prevent clot formation.Dietary modifications may include the restriction of sodium and use of dietary supplements as appropriate for the nature and extent of malnutrition. Fluids may be restricted to help control swelling. Children with this disease require diets high in calories and protein, and many patients require a feeding tube (nasogastric tube or gastrostomy tube (g-tube)) for medication and/or feeds. Some patients develop oral aversions and will use the tube for all feeds.