The treatment of kidney damage may reverse or delay the progression of the disease. Kidney damage is treated by prescribing drugs:

- Corticosteroids: the result is a decrease in the proteinuria and the risk of infection as well as a resolution of the edema. Prednisone is usually prescribed at a dose of 60 mg/m² of body surface area/day in a first treatment for 4–8 weeks. After this period the dose is reduced to 40 mg/m² for a further 4 weeks. Patients suffering a relapse or children are treated with prednisolone 2 mg/kg/day till urine becomes negative for protein. Then, 1.5 mg/kg/day for 4 weeks. Frequent relapses treated by: cyclophosphamide or nitrogen mustard or cyclosporin or levamisole. Patients can respond to prednisone in a number of different ways:

- Corticosteroid sensitive patient or early steroid-responder: the subject responds to the corticosteroids in the first 8 weeks of treatment. This is demonstrated by a strong diuresis and the disappearance of edemas, and also by a negative test for proteinuria in three urine samples taken during the night.

- Corticosteroid resistant patient or late steroid-responder: the proteinuria persists after the 8-week treatment. The lack of response is indicative of the seriousness of the glomerular damage, which could develop into chronic kidney failure.

- Corticosteroid tolerant patient: complications such as hypertension appear, patients gain a lot of weight and can develop aseptic or avascular necrosis of the hip or knee, cataracts and thrombotic phenomena and/or embolisms.

- Corticosteroid dependent patient: proteinuria appears when the dose of corticosteroid is decreased or there is a relapse in the first two weeks after treatment is completed.

The susceptibility testing in vitro to glucocorticoids on patient's peripheral blood mononuclear cells is associated with the incidence of not optimal clinical responses: the most sensitive patients in vitro have shown a higher incidence of corticodependence, while the most resistant patients in vitro showed a higher incidence of ineffective therapy.

- Immunosupressors (cyclophosphamide): only indicated in recurring nephrotic syndrome in corticosteroid dependent or intolerant patients. In the first two cases the proteinuria has to be negated before treatment with the immunosuppressor can begin, which involves a prolonged treatment with prednisone. The negation of the proteinuria indicates the exact moment when treatment with cyclophosphamide can begin. The treatment is continued for 8 weeks at a dose of 3 mg/kg/day, the immunosuppression is halted after this period. In order to be able to start this treatment the patient should not be suffering from neutropenia nor anaemia, which would cause further complications. A possible side effect of the cyclophosphamide is alopecia. Complete blood count tests are carried out during the treatment in order to give advance warning of a possible infection.

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.

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.

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.

The ideal treatment for IgAN would remove IgA from the glomerulus and prevent further IgA deposition. This goal still remains a remote prospect. There are a few additional caveats that have to be considered while treating IgA nephropathy. IgA nephropathy has a very variable course, ranging from a benign recurrent hematuria up to a rapid progression to chronic kidney failure. Hence the decision on which patients to treat should be based on the prognostic factors and the risk of progression. Also, IgA nephropathy recurs in transplants despite the use of ciclosporin, azathioprine or mycophenolate mofetil and steroids in these patients. There are persisting uncertainties, due to the limited number of patients included in the few controlled randomized studies performed to date, which hardly produce statistically significant evidence regarding the heterogeneity of IgA nephropathy patients, the diversity of study treatment protocols, and the length of follow-up.

Patients with isolated hematuria, proteinuria < 1 g/day and normal renal function have a benign course and are generally just followed up annually. In cases where tonsillitis is the precipitating factor for episodic hematuria, tonsillectomy has been claimed to reduce the frequency of those episodes. However, it does not reduce the incidence of progressive kidney failure. Also, the natural history of the disease is such that episodes of frank hematuria reduce over time, independent of any specific treatment. Similarly, prophylactic antibiotics have not been proven to be beneficial. Dietary gluten restriction, used to reduce mucosal antigen challenge, also has not been shown to preserve kidney function. Phenytoin has also been tried without any benefit.

A subset of IgA nephropathy patients, who have minimal change disease on light microscopy and clinically have nephrotic syndrome, show an exquisite response to steroids, behaving more or less like minimal change disease. In other patients, the evidence for steroids is not compelling. Short courses of high dose steroids have been proven to lack benefit. However, in patients with preserved renal function and proteinuria (1-3.5 g/day), a recent prospective study has shown that 6 months regimen of steroids may lessen proteinuria and preserve renal function. However, the risks of long-term steroid use have to be weighed in such cases. It should be noted that the study had 10 years of patient follow-up data, and did show a benefit for steroid therapy; there was a lower chance of reaching end-stage renal disease (renal function so poor that dialysis was required) in the steroid group. Importantly, angiotensin-converting enzyme inhibitors were used in both groups equally.

Cyclophosphamide had been used in combination with anti-platelet/anticoagulants in unselected IgA nephropathy patients with conflicting results. Also, the side effect profile of this drug, including long term risk of malignancy and sterility, made it an unfavorable choice for use in young adults. However, one recent study, in a carefully selected high risk population of patients with declining GFR, showed that a combination of steroids and cyclophosphamide for the initial 3 months followed by azathioprine for a minimum of 2 years resulted in a significant preservation of renal function. Other agents such as mycophenolate mofetil, ciclosporin and mizoribine have also been tried with varying results.

A study from Mayo Clinic did show that long term treatment with omega-3 fatty acids results in reduction of progression to kidney failure, without, however, reducing proteinuria in a subset of patients with high risk of worsening kidney function. However, these results have not been reproduced by other study groups and in two subsequent meta-analyses. However, fish oil therapy does not have the drawbacks of immunosuppressive therapy. Also, apart from its unpleasant taste and abdominal discomfort, it is relatively safe to consume.

The events that tend to progressive kidney failure are not unique to IgA nephropathy and non-specific measures to reduce the same would be equally useful. These include low-protein diet and optimal control of blood pressure. The choice of the antihypertensive agent is open as long as the blood pressure is controlled to desired level. However, Angiotensin converting enzyme inhibitors and Angiotensin II receptor antagonists are favoured due to their anti-proteinuric effect.

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.

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.

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.

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.

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.

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.

Treatment consists of addressing the cause, such as by removing an offending drug. There is no clear evidence that corticosteroids help.

Nutrition therapy consists of adequate fluid intake, which can require several liters of extra fluid.

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.

There is as yet inadeqaute data from randomised controlled trials.

Treatment with HAART and ACE inhibitors/Angiotensin receptor blockers has been shown to be beneficial and should be given to all patients unless otherwise contra-indicated. General renoprotective measures and the treatment of the complications of nephrotic syndrome and kidney failure are adjunctive.

Corticosteroid treatment can be useful in patients who do not respond to the above treatment. There is some evidence that ciclosporin might be helpful in selective cases, however further trials are required on both steroids and ciclosporin before these drugs can become standardised treatment if at all.

People who received earlier referrals to a nephrology specialist, meaning a longer time before they had to start dialysis, had a shorter initial hospitalization and reduced risk of death after the start of dialysis. The authors highlighted the resulting importance of early referral in slowing progression of chronic kidney disease. Other methods of reducing disease progression include minimizing exposure to nephrotoxins such as NSAIDS and intravenous contrast.

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.

Drug regimens prescribed for lupus nephritis include mycophenolate mofetil (MMF), intravenous cyclophosphamide with corticosteroids, and the immune suppressant azathioprine with corticosteroids. MMF and cyclophosphamide with corticosteroids are equally effective in achieving remission of the disease. MMF is safer than cyclophosphamide with corticosteroids, with less chance of causing ovarian failure, immune problems or hair loss. It also works better than azathioprine with corticosteroids for maintenance therapy. Individuals with lupus nephritis have a high risk for B-cell lymphoma (which begins in the immune system cells).

In non-diabetics and people with type 1 diabetes, a low protein diet is found to have a preventative effect on progression of chronic kidney disease. However, this effect does not apply to people with type 2 diabetes. A whole food, plant-based diet may help some people with kidney disease. A high protein diet from either animal or plant sources appears to have negative effects on kidney function at least in the short term.

The kidneys are the only body system that are directly affected by tubulointerstitial nephritis. Kidney function is usually reduced; the kidneys can be just slightly dysfunctional, or fail completely.

In chronic tubulointerstitial nephritis, the most serious long-term effect is kidney failure. When the proximal tubule is injured, sodium, potassium, bicarbonate, uric acid, and phosphate reabsorption may be reduced or changed, resulting in low bicarbonate, known as metabolic acidosis, low potassium, low uric acid known as hypouricemia, and low phosphate known as hypophosphatemia. Damage to the distal tubule may cause loss of urine-concentrating ability and polyuria.

In most cases of acute tubulointerstitial nephritis, the function of the kidneys will return after the harmful drug is not taken anymore, or when the underlying disease is cured by treatment. If the illness is caused by an allergic reaction, a corticosteroid may speed the recovery kidney function; however, this is often not the case.

Chronic tubulointerstitial nephritis has no cure. Some patients may require dialysis. Eventually, a kidney transplant may be needed.

Analgesics may be needed for the abdominal and joint pains. It is uncertain as to whether HSP needs treatment beyond controlling the symptoms. Most patients do not receive therapy because of the high spontaneous recovery rate. Steroids are generally avoided. However, if they are given early in the disease episode, the duration of symptoms may be shortened, and abdominal pain can improve significantly. Moreover, the chance of severe kidney problems may be reduced. A systematic review of randomized clinical trials did not find any evidence that steroid treatment (prednisone) is effective at decreasing the likelihood of developing long-term kidney disease.

Evidence of worsening kidney damage would normally prompt a kidney biopsy. Treatment may be indicated on the basis of the appearance of the biopsy sample; various treatments may be used, ranging from oral steroids to a combination of intravenous methylprednisolone (steroid), cyclophosphamide and dipyridamole followed by prednisone. Other regimens include steroids/azathioprine, and steroids/cyclophosphamide (with or without heparin and warfarin). Intravenous immunoglobulin (IVIG) is occasionally used.

There is no evidence from randomized clinical trials that treating children who have HSP with antiplatelet agent prevents persistent kidney disease. There is also no evidence from randomized clinical trials that treating children or adults with cyclophosphamide prevents severe kidney disease. Heparin treatment is not justified.

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.

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.

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.

There are three main mechanisms to cause proteinuria:

- Due to disease in the glomerulus

- Because of increased quantity of proteins in serum (overflow proteinuria)

- Due to low reabsorption at proximal tubule (Fanconi syndrome)

Proteinuria can also be caused by certain biological agents, such as bevacizumab (Avastin) used in cancer treatment. Excessive fluid intake (drinking in excess of 4 litres of water per day) is another cause.

Also leptin administration to normotensive Sprague Dawley rats during pregnancy significantly increases urinary protein excretion.

Proteinuria may be a sign of renal (kidney) damage. Since serum proteins are readily reabsorbed from urine, the presence of excess protein indicates either an insufficiency of absorption or impaired filtration. People with diabetes may have damaged nephrons and develop proteinuria. The most common cause of proteinuria is diabetes, and in any person with proteinuria and diabetes, the cause of the underlying proteinuria should be separated into two categories: diabetic proteinuria versus the field.

With severe proteinuria, general hypoproteinemia can develop which results in

diminished oncotic pressure. Symptoms of diminished oncotic pressure may include ascites, edema and hydrothorax.