In children and some adults, FSGS presents as a nephrotic syndrome, which is characterized by edema (associated with weight gain), hypoalbuminemia (low serum albumin, a protein in the blood), hyperlipidemia and hypertension (high blood pressure). In adults, it may also present as kidney failure and proteinuria, without a full-blown nephrotic syndrome.

Minimal change disease has been called by many other names in the medical literature, including minimal change nephropathy, minimal change nephrosis, minimal change nephrotic syndrome, minimal change glomerulopathy, foot process disease (referring to the foot processes of the podocytes), nil disease (referring to the lack of pathologic findings on light microscopy), nil lesions, lipid nephrosis, and lipoid nephrosis.

Management of sickle nephropathy is not separate from that of overall patient management. In addition, however, the use of ACE inhibitors has been associated with improvement of the hyperfiltration glomerulopathy. Three-year graft and patient survival in kidney transplant recipients with sickle nephropathy is lower when compared to those with other causes of end-stage kidney disease.

Early and aggressive treatment is required to control the disorder. Diuretic medications help rid the body of excess fluid. 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. Antibiotics may be needed to control infections. Patients may also take iron supplements, potassium chloride, thyroxine and other vitamins to replenish what minerals the kidneys have leaked out.

Most patients will undergo regular and frequent albumin infusion (often daily) to replace what kidneys have lost. Infusions are performed via IV so a central venous catheter will need to be surgically inserted into patients chest or groin.

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.

Many patients have a gastrostomy tube (g-tube) inserted for medication and/or feeds. Some patients develop oral aversions and will use the tube for all feeds. Other patients eat well and only use the tube for medicine or supplemental feeds. The tube is also useful for patients needing to drink large amounts of fluids around the time of transplant.

Patient will require removal of the kidneys (one at the time or both), dialysis, and ultimately a kidney transplant.

The treatment of nephrotic syndrome can be symptomatic or can directly address the injuries caused to the kidney.

Congenital nephrotic syndrome can be successfully controlled with early diagnosis and aggressive treatment including albumin infusions, nephrectomy, medications and ultimately a kidney transplant. Most children live fairly normal life post-transplant but will spend significant time hospitalised pre-transplant and have numerous surgeries to facilitate treatment.

Due to the protein (albumin) losses many patients have reduced muscle tone and may experience delays in certain physical milestones such as sitting, crawling and walking. Similarly many patients experience growth delays due to protein loss. Delays vary from mild to significant but most patients experience growth spurts once they receive their transplanted kidney. Physical therapy may be useful for the child to strengthen muscle tone.

Undiagnosed cases are often fatal in the first year due to blood clots, infections or other complications.

There are currently several known genetic causes of the hereditary forms of FSGS.

Some researchers found SuPAR as a cause of FSGS.

Another gene that has been associated with this syndrome is the COL4A5 gene.

Treating proteinuria mainly needs proper diagnosis of the cause.

The most common cause is diabetic nephropathy; in this case, proper glycemic control may slow the progression. Medical management consists of angiotensin converting enzyme (ACE) inhibitors, which are typically first-line therapy for proteinuria. In patients whose proteinuria is not controlled with ACE inhibitors, the addition of an aldosterone antagonist (i.e., spironolactone) or angiotensin receptor blocker (ARB) may further reduce protein loss. Caution must be used if these agents are added to ACE inhibitor therapy due to the risk of hyperkalemia.

Proteinuria secondary to autoimmune disease should be treated with steroids or steroid-sparing agent plus the use of ACE inhibitors.

The objective of this treatment is to treat the imbalances brought about by the illness: edema, hypoalbuminemia, hyperlipemia, hypercoagulability and infectious complications.

- Edema: a return to an unswollen state is the prime objective of this treatment of nephrotic syndrome. It is carried out through the combination of a number of recommendations:

- Rest: depending on the seriousness of the edema and taking into account the risk of thrombosis caused by prolonged bed rest.

- Medical nutrition therapy: based on a diet with the correct energy intake and balance of proteins that will be used in synthesis processes and not as a source of calories. A total of 35 kcal/kg body weight/day is normally recommended. This diet should also comply with two more requirements: the first is to not consume more than 1 g of protein/kg body weight/ day, as a greater amount could increase the degree of proteinuria and cause a negative nitrogen balance. Patients are usually recommended lean cuts of meat, fish, and poultry. The second guideline requires that the amount of water ingested is not greater than the level of diuresis. In order to facilitate this the consumption of salt must also be controlled, as this contributes to water retention. It is advisable to restrict the ingestion of sodium to 1 or 2 g/day, which means that salt cannot be used in cooking and salty foods should also be avoided. Foods high in sodium include seasoning blends (garlic salt, Adobo, season salt, etc.) canned soups, canned vegetables containing salt, luncheon meats including turkey, ham, bologna, and salami, prepared foods, fast foods, soy sauce, ketchup, and salad dressings. On food labels, compare milligrams of sodium to calories per serving. Sodium should be less than or equal to calories per serving.

- Medication: The pharmacological treatment of edema is based on the prescription of diuretic drugs (especially loop diuretics, such as furosemide). In severe cases of edema (or in cases with physiological repercussions, such as scrotal, preputial or urethral edema) or in patients with one of a number of severe infections (such as sepsis or pleural effusion), the diuretics can be administered intravenously. This occurs where the risk from plasmatic expansion is considered greater than the risk of severe hypovolemia, which can be caused by the strong diuretic action of intravenous treatment. The procedure is the following:

- Hypoalbuminemia: is treated using the medical nutrition therapy described as a treatment for edema. It includes a moderate intake of foods rich in animal proteins.

- Hyperlipidaemia: depending of the seriousness of the condition it can be treated with medical nutrition therapy as the only treatment or combined with drug therapy. The ingestion of cholesterol should be less than 300 mg/day, which will require a switch to foods that are low in saturated fats. Avoid saturated fats such as butter, cheese, fried foods, fatty cuts of red meat, egg yolks, and poultry skin. Increase unsaturated fat intake, including olive oil, canola oil, peanut butter, avocadoes, fish and nuts. In cases of severe hyperlipidaemia that are unresponsive to nutrition therapy the use of hypolipidemic drugs, may be necessary (these include statins, fibrates and resinous sequesters of bile acids).

- Thrombophilia: low molecular weight heparin (LMWH) may be appropriate for use as a prophylactic in some circumstances, such as in asymptomatic patients that have no history of suffering from thromboembolism. When the thrombophilia is such that it leads to the formation of blood clots, heparin is given for at least 5 days along with oral anticoagulants (OAC). During this time and if the prothrombin time is within its therapeutic range (between 2 and 3), it may be possible to suspend the LMWH while maintaining the OACs for at least 6 months.

- Infectious complications: an appropriate course of antibacterial drugs can be taken according to the infectious agent.

In addition to these key imbalances, vitamin D and calcium are also taken orally in case the alteration of vitamin D causes a severe hypocalcaemia, this treatment has the goal of restoring physiological levels of calcium in the patient.

- Achieving better blood glucose level control if the patient is diabetic.

- Blood pressure control. ACE inhibitors are the drug of choice. Independent of their blood pressure lowering effect, they have been shown to decrease protein loss.

Corticosteroids such as prednisone are often prescribed along with a blood pressure medication, typically an ACE inhibitor such as lisinopril. Some nephrologists will start out with the ACE inhibitor first in an attempt to reduce the blood pressure's force which pushes the protein through the cell wall in order to lower the amount of protein in the urine. In some cases, a corticosteroid may not be necessary if the case of minimal change disease is mild enough to be treated just with the ACE inhibitor. Often, the liver is overactive with minimal change disease in an attempt to replace lost protein and overproduces cholesterol. Therefore, a statin drug is often prescribed for the duration of the treatment. When the urine is clear of protein, the medications can be discontinued. Fifty percent of patients will relapse and need further treatment with immunosuppressants, such as cyclosporine and tacrolimus.

Minimal change disease usually responds well to initial treatment and over 90% of patients will respond to oral steroids within 6–8 weeks, with most of these having a complete remission. Symptoms of nephrotic syndrome (NS) typically go away; but, this can take from 2 weeks to many months. Younger children, who are more likely to develop minimal change disease, usually respond faster than adults. In 2 out of 3 children with minimal change disease; however, the symptoms of NS can recur, called a relapse, particularly after an infection or an allergic reaction. This is typical and usually requires additional treatment. Many children experience 3 to 4 relapses before the disease starts to go away. Some children require longer term therapy to keep MCD under control. It appears that the more time one goes without a relapse, the better the chances are that a relapse will not occur. In most children with minimal change disease, particularly among those who respond typically, there is minimal to no permanent damage observed in their kidneys.

With corticosteroid treatment, most cases of nephrotic syndrome from minimal change disease in children will go into remission. This typically occurs faster, over 2 to 8 weeks, in younger children, but can take up to 3 or 4 months in adults. Typically, the dose of corticosteroids will initially be fairly high, lasting 1or 2 months. When urine protein levels have normalised, corticosteroids are gradually withdrawn over several weeks (to avoid triggering an Addisonian crisis). Giving corticosteroids initially for a longer period of time is thought to reduce the likelihood of relapse. The majority of children with minimal change disease will respond to this treatment.

Even among those who respond well to corticosteroids initially, it is common to observe periods of relapse (return of nephrotic syndrome symptoms). 80% of those who get minimal change disease have a recurrence. Because of the potential for relapse, the physician may prescribe and teach the patient how to use a tool to have them check urine protein levels at home. Two out of 3 children who initially responded to steroids will experience this at least once. Typically the steroids will be restarted when this occurs, although the total duration of steroid treatment is usually shorter during relapses than it is during the initial treatment of the disease.

There are several immunosuppressive medications that can be added to steroids when the effect is insufficient or can replace them if intolerance or specific contraindications are encountered.

Though there is some evidence that dietary interventions (to lower red meat intake) can be helpful in lowering albuminuria levels, there is currently no evidence that low protein interventions correlate to improvement in kidney function. Among other measures, blood pressure control, especially with the use of inhibitors of the renin-angiotensin-system, is the most commonly used therapy to control albuminuria.

Osmotic nephrosis refers to structural changes that occur at the cellular level in the human kidney. Cells, primarily of the straight proximal tubule, swell due to the formation of large vacuoles in the cytoplasm. These vacuoles occur in the presence of large amounts of certain solutes circulating in the tubules. However, despite the condition's name, the solutes do not cause change through osmotic forces but through pinocytosis. Once inside the cytoplasm, pinocytic vacuoles combine with each other and with lysosomes to form large vacuoles that appear transparent under microscopic examination.

There may be no symptomatic presentation with this condition, or it may confused with other nephrotic conditions such as Tubular calcineurin-inhibitor toxicity. Affected cells of the proximal tubule may be passed in the urine, but a kidney biopsy is the only sure way to make a diagnosis.

Responsible exogenous solutes include sucrose-containing IVIg, mannitol, dextran, contrast dye, and hydroxyethyl starch. Prevention includes standard preventions for iatrogenic kidney damage. Osmotic nephrosis is usually reversible but can lead to chronic renal failure.

The epidemiology of rapidly progressive glomerulonephritis according to Hedger, et al., is an incidence rate of 3.9 individuals per million (3.3–4.7) with a 95% confidence intervals.

The frequency is unknown, but the disease is considered to be very rare.

Therapy for rapidly progressive glomerulonephritis is done via corticosteroids and cyclophosphamide. The predictor of kidney survival is serum creatinine value. The substitution of azathioprine for cyclophosphamide after a 90-day initial period is another option.Plasmapheresis can be used for patients who present with severe renal failure.

There is a genetic predisposition, first-degree relatives have a great increase in the chance of VUR. The gene frequency is estimated to be 1:600. The American Academy of Pediatrics recommends that children from 2 to 24 months presenting with a UTI should be investigated for VUR.

The aim of treatment is to reduce renal scarring. Those children with grade II or worse should receive low dose prophylactic antibiotics (Nitrofurantoin, trimethoprim, cotrimoxazole, cefalexin in those with CRF). Hypertension should be managed with ACE inhibitor or ARBs. Other treatment modalities include surgery (endoscopic injection of collagen behind the intra-vesical ureter, ureteric re-implantation or lengthening of the submucosal ureteric tunnel) which has its protagonists.

Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine (bilirubinuria), retrograde ejaculation, pneumaturia (air bubbles in the urine) due to a fistula, or drugs such as pyridium.

Nephrosis is any of various forms of kidney disease (nephropathy). In an old and broad sense of the term, it is any nephropathy, but in current usage the term is usually restricted to a narrower sense of nephropathy without inflammation or neoplasia, in which sense it is distinguished from nephritis, which involves inflammation. It is also defined as any purely degenerative disease of the renal tubules. Nephrosis is characterized by a set of signs called the nephrotic syndrome. Nephrosis can be a primary disorder or can be secondary to another disorder. Nephrotic complications of another disorder can coexist with nephritic complications. In other words, nephrosis and nephritis can be pathophysiologically contradistinguished, but that does not mean that they cannot occur simultaneously.

Types of nephrosis include amyloid nephrosis and osmotic nephrosis.

Diabetic nephropathy in type 2 diabetes can be more difficult to predict because the onset of diabetes is not usually well established. Without intervention, 20-40 percent of patients with type 2 diabetes/microalbuminuria, will evolve to macroalbuminuria.

Diabetic nephropathy is the most common cause of end-stage kidney disease, which may require hemodialysis or even kidney transplantation. It is associated with an increased risk of death in general, particularly from cardiovascular disease.

The goals of treatment are to slow the progression of kidney damage and control related complications. The main treatment, once proteinuria is established, is ACE inhibitor medications, which usually reduce proteinuria levels and slow the progression of diabetic nephropathy. Other issues that are important in the management of this condition include control of high blood pressure and blood sugar levels (see diabetes management), as well as the reduction of dietary salt intake.

Treatment of secondary membranous nephropathy is guided by the treatment of the original disease. For treatment of idiopathic membranous nephropathy, the treatment options include immunosuppressive drugs and non-specific anti-proteinuric measures. Recommended first line therapy often includes: cyclophosphamide alternating with a corticosteroid.

Perhaps the most difficult aspect of membranous glomerulonephritis is deciding which people to treat with immunosuppressive therapy as opposed to simple "background" or anti-proteinuric therapies. A large part of this difficulty is due to a lack of ability to predict which people will progress to end-stage renal disease, or renal disease severe enough to require dialysis. Because the above medications carry risk, treatment should not be initiated without careful consideration as to risk/benefit profile. Of note, corticosteroids (typically Prednisone) alone are of little benefit. They should be combined with one of the other 5 medications, each of which, along with prednisone, has shown some benefit in slowing down progression of membranous nephropathy. It must be kept in mind, however, that each of the 5 medications also carry their own risks, on top of prednisone.

The twin aims of treating membranous nephropathy are first to induce a remission of the nephrotic syndrome and second to prevent the development of endstage renal failure. A meta-analysis of four randomized controlled studies comparing treatments of membranous nephropathy showed that regimes comprising chlorambucil or cyclophosphamide, either alone or with steroids, were more effective than symptomatic treatment or treatment with steroids alone in inducing remission of the nephrotic syndrome.

Sickle cell nephropathy is a type of nephropathy associated with sickle cell disease which causes kidney complications as a result of sickling of red blood cells in the small blood vessels. The hypertonic and relatively hypoxic environment of the renal medulla, coupled with the slow blood flow in the vasa recta, favors sickling of red blood cells, with resultant local infarction (papillary necrosis). Functional tubule defects in patients with sickle cell disease are likely the result of partial ischemic injury to the renal tubules.

Also the sickle cell disease in young patients is characterized by renal hyperperfusion, glomerular hypertrophy, and glomerular hyperfiltration. Many of these individuals eventually develop a glomerulopathy leading to glomerular proteinuria (present in as many as 30%) and, in some, the nephrotic syndrome. Co-inheritance of microdeletions in the -globin gene (thalassemia) appear to protect against the development of nephropathy and are associated with lower mean arterial pressure and less protein in the urine.

Mild increases in the blood levels of nitrogen and uric acid can also develop. Advanced kidney failure and high blood urea levels occur in 10% of cases. Pathologic examination reveals the typical lesion of "hyperfiltration nephropathy" namely, focal segmental glomerular sclerosis. This finding has led to the suggestion that anemia-induced hyperfiltration in childhood is the principal cause of the adult glomerulopathy. Nephron loss secondary to ischemic injury also contributes to the development of azotemia in these patients.

In addition to the glomerulopathy described above, kidney complications of sickle cell disease include cortical infarcts leading to loss of function, persistent bloody urine, and perinephric hematomas. Papillary infarcts, demonstrable radiographically in 50% of patients with sickle trait, lead to an increased risk of bacterial infection in the scarred kidney tissues and functional tubule abnormalities. The presence of visible blood in the urine without pain occurs with a higher frequency in sickle trait than in sickle cell disease and likely results from infarctive episodes in the renal medulla. Functional tubule abnormalities such as nephrogenic diabetes insipidus result from marked reduction in vasa recta blood flow, combined with ischemic tubule injury. This concentrating defect places these patients at increased risk of dehydration and, hence, sickling crises. The concentrating defect also occurs in individuals with sickle trait. Other tubule defects involve potassium and hydrogen ion excretion, occasionally leading to high blood potassium, metabolic acidosis, and a defect in uric acid excretion which, combined with increased purine synthesis in the bone marrow, results in high blood uric acid levels.

Albuminuria is a pathological condition wherein the protein albumin is abnormally present in the urine. It is a type of proteinuria. Albumin is a major plasma protein (normally circulating in the blood); in healthy people, only trace amounts of it are present in urine, whereas larger amounts occur in the urine of patients with kidney disease. For a number of reasons, clinical terminology is changing to focus on albuminuria more than proteinuria.