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.

Male gender, proteinuria (especially > 2 g/day), hypertension, smoking, hyperlipidemia, older age, familial disease and elevated creatinine concentrations are markers of a poor outcome. Frank hematuria has shown discordant results with most studies showing a better prognosis, perhaps related to the early diagnosis, except for one group which reported a poorer prognosis. Proteinuria and hypertension are the most powerful prognostic factors in this group.

There are certain other features on kidney biopsy such as interstitial scarring which are associated with a poor prognosis. ACE gene polymorphism has been recently shown to have an impact with the DD genotype associated more commonly with progression to kidney failure.

About a third of untreated patients have spontaneous remission, another third progress to require dialysis and the last third continue to have proteinuria, without progression of renal failure.

Acute glomerulonephritis resulted in 19,000 deaths in 2013 down from 24,000 deaths in 1990.

It is unclear whether or not acute proliferative glomerulonephritis (i.e., poststreptococcal glomerulonephritis) can be prevented with early prophylactic antibiotic therapy, with some authorities arguing that antibiotics can prevent development of acute proliferative glomerulonephritis, while others reject that antibiotics can prevent acute proliferative glomerulonephritis.

The remainder is secondary due to:

- autoimmune conditions (e.g., systemic lupus erythematosus)

- infections (e.g., syphilis, malaria, hepatitis B, hepatitis C)

- drugs (e.g., captopril, NSAIDs, penicillamine, probenecid).

- inorganic salts (e.g. gold, mercury).

- tumors, frequently solid tumors of the lung and colon; hematological malignancies such as chronic lymphocytic leukemia are less common.

Glomerulonephritis (GN), also known as glomerular nephritis, is a term used to refer to several kidney diseases (usually affecting both kidneys). Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the name, but not all diseases necessarily have an inflammatory component.

As it is not strictly a single disease, its presentation depends on the specific disease entity: it may present with isolated hematuria and/or proteinuria (blood or protein in the urine); or as a nephrotic syndrome, a nephritic syndrome, acute kidney injury, or chronic kidney disease.

They are categorized into several different pathological patterns, which are broadly grouped into non-proliferative or proliferative types. Diagnosing the pattern of GN is important because the outcome and treatment differs in different types. Primary causes are intrinsic to the kidney. Secondary causes are associated with certain infections (bacterial, viral or parasitic pathogens), drugs, systemic disorders (SLE, vasculitis), or diabetes.

Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that is characterized by a rapid loss of renal function, (usually a 50% decline in the glomerular filtration rate (GFR) within 3 months) with glomerular crescent formation seen in at least 50% or 75% of glomeruli seen on kidney biopsies. If left untreated, it rapidly progresses into acute renal failure and death within months. In 50% of cases, RPGN is associated with an underlying disease such as Goodpasture syndrome, systemic lupus erythematosus or granulomatosis with polyangiitis; the remaining cases are idiopathic. Regardless of the underlying cause, RPGN involves severe injury to the kidneys' glomeruli, with many of the glomeruli containing characteristic glomerular crescents (crescent-shaped scars).

Glomerulonephritis refers to an inflammation of the glomerulus, which is the unit involved in filtration in the kidney. This inflammation typically results in one or both of the nephrotic or nephritic syndromes.

The cause of lupus nephritis, a genetic predisposition, plays role in lupus nephritis. Multiple genes, many of which are not yet identified, mediate this genetic predisposition.

The immune system protects the human body from infection, with immune system problems it cannot distinguish between harmful and healthy substances. Lupus nephritis affects approximately 3 out of 10,000 people.

The prognosis for nephrotic syndrome under treatment is generally good although this depends on the underlying cause, the age of the patient and their response to treatment. It is usually good in children, because minimal change disease responds very well to steroids and does not cause chronic renal failure. Any relapses that occur become less frequent over time; the opposite occurs with mesangiocapillary glomerulonephritis, in which the kidney fails within three years of the disease developing, making dialysis necessary and subsequent kidney transplant. In addition children under the age of 5 generally have a poorer prognosis than prepubescents, as do adults older than 30 years of age as they have a greater risk of kidney failure.

Other causes such as focal segmental glomerulosclerosis frequently lead to end stage renal disease. Factors associated with a poorer prognosis in these cases include level of proteinuria, blood pressure control and kidney function (GFR).

Without treatment nephrotic syndrome has a very bad prognosis especially "rapidly progressing glomerulonephritis", which leads to acute kidney failure after a few months.

Men are affected three times as often as women. There is also marked geographic variation in the prevalence of IgA nephropathy throughout the world. It is the most common glomerular disease in the Far East and Southeast Asia, accounting for almost half of all the patients with glomerular disease. However, it accounts for only about 25% of the proportion in European and about 10% among North Americans, with African–Americans having a very low prevalence of about 2%. However, a confounding factor in this analysis is the existing policy of screening and use of kidney biopsy as an investigative tool. School children in Japan undergo routine urinalysis (as do army recruits in Singapore) and any suspicious abnormality is pursued with a kidney biopsy, which might partly explain the high observed incidence of IgA nephropathy in those countries.

Nephrotic syndrome can affect any age, although it is mainly found in adults with a ratio of adults to children of 26 to 1.

The syndrome presents in different ways in the two groups: the most frequent glomerulopathy in children is minimal change disease (66% of cases), followed by focal segmental glomerulosclerosis (8%) and mesangiocapillary glomerulonephritis (6%). In adults the most common disease is mesangiocapillary glomerulonephritis (30-40%), followed by focal and segmental glomeruloesclerosis (15-25%) and minimal change disease (20%). The latter usually presents as secondary and not primary as occurs in children. Its main cause is diabetic nephropathy. It usually presents in a patient’s 40s or 50s.

Of the glomerulonephritis cases approximately 60% to 80% are primary, while the remainder are secondary.

There are also differences in epidemiology between the sexes, the disease is more common in men than in women by a ratio of 2 to 1.

The epidemiological data also reveals information regarding the most common way that symptoms develop in patients with nephrotic syndrome: spontaneous remission occurs in up to 20% or 30% of cases during the first year of the illness. However, this improvement is not definitive as some 50% to 60% of patients die and / or develop chronic renal failure 6 to 14 years after this remission. On the other hand, between 10% and 20% of patients have continuous episodes of remissions and relapses without dying or jeopardizing their kidney. The main causes of death are cardiovascular, as a result of the chronicity of the syndrome, and thromboembolic accidents.

Depending on the cause, a proportion of patients (5–10%) will never regain full kidney function, thus entering end-stage kidney failure and requiring lifelong dialysis or a kidney transplant. Patients with AKI are more likely to die prematurely after being discharged from hospital, even if their kidney function has recovered.

The risk of developing chronic kidney disease is increased (8.8-fold).

Glomerulonephrosis is a non-inflammatory disease of the kidney (nephrosis) presenting primarily in the glomerulus (a glomerulopathy).

It can be contrasted to glomerulonephritis, which implies inflammation.

It can be caused by diethylnitrosamine.

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.

The pathophysiology of lupus nephritis has autoimmunity contributing significantly. Autoantibodies direct themselves against nuclear elements. The characteristics of nephritogenic autoantibodies ( lupus nephritis) are: antigen specificity directed at nucleosome, high affinity autoantibodies form intravascular immune complexes, autoantibodies of certain isotypes activate complement.

It is characterized by glomerular basement membrane thickening (referred to as "tram-tracking of the basement membrane"), increased mesangial matrix and segmental and global glomerulosclerosis.

The differential diagnosis of tram-tracking includes membranoproliferative glomerulonephritis (especially hepatitis C), and thrombotic microangiopathies.

Mortality after AKI remains high. Overall it is 20%, 30% if the patient is referred to nephrology, 50% if dialyzed, and 70% if on ICU.

If AKI develops after major surgery (13.4% of all people who have undergone major surgery) the risk of death is markedly increased (over 12-fold).

Transplant glomerulopathy, abbreviated TG, is a disease of the glomeruli in transplanted kidneys. It is a type of renal injury often associated with chronic antibody-mediated rejection. However, transplant glomerulopathy is not specific for chronic antibody-mediated rejection; it may be the result of a number of disease processes affecting the glomerular endothelium.

Despite expensive treatments, lupus nephritis remains a major cause of morbidity and mortality in people with relapsing or refractory lupus nephritis.

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.

Due to the complex malarial syndrome, there are many pathogenic interactions leading to acute renal failure, such as hypovolemia, intravascular hemolysis and disseminated intravascular coagulation. Malarial acute renal failure prevents the kidneys from efficiently removing excess fluid, electrolytes and waste material from the blood. The accumulation of these fluids and material will cause adverse consequences for the patient including, electrolyte abnormality and increased urinary protein excretion.

Untreated patients often face a large number of physical complications, but early diagnosis and effective treatment can reduce the high risk of mortality in patients. A three-pronged approach against infection is regularly needed for successful treatment. antimalarial drug therapy (e.g., artemisinin derivatives), fluid replacement (e.g., oral rehydration therapy), and if needed, renal replacement therapy.

The long-term use of lithium, a medication commonly used to treat bipolar disorder and schizoaffective disorders, is known to cause nephropathy.

Malarial nephropathies are reported in endemic areas, such as Southeast Asia, India, and Sub-Saharan Africa. The pathogenesis of acute renal failure in severe malaria is unspecific and multifactorial—it affects fewer than 4.8 percent of cases, but reports a high risk of mortality (15 to 45 percent). Histologic evidence shows a large combination of pathogenic mechanisms at play—acute tubular necrosis, interstitial nephritis and glomerulonephritis. Risk factors for malarial acute renal failure include delayed diagnosis, high parasitemia, and clinical presentation of oliguria, low blood pressure, severe anemia, and jaundice. In addition, patients already suffering from diarrhea, hepatitis, or respiratory distress have a worse prognosis.