Purpura<unk>  is caused by extensive inflammatory damage to the glomerulus capillaries, which is associated with a variety of medical conditions that we will discuss. Furthermore, the cause of this inflammation can be infectious, autoimmune, or thrombotic. The causative conditions can be divided conveniently between age groups as follows, though it is important to note that many of the conditions listed in children/adolescents can also occur in adults with lower frequency, and vice versa: Children/adolescents * IgA nephropathy (Note: Contrast time of onset with Post-streptococcal Glomerulonephritis) - Most commonly diagnosed in children who recently had an upper respiratory tract infection (URI). Symptoms typically present within 1–2 days of a non-specific URI with severe flank/abdominal pain, gross hematuria (characterized by dark brown or red colored urine), and edema of the hands, feet, and/or face. * Post-streptococcal glomerulonephritis (PSGN) - Similar to IgA nephropathy, post-streptococcal glomerulonephritis (PSGN) most often occurs in children who have recently had an upper respiratory infection (URI). In contrast with IgA nephropathy, however, PSGN typically presents 2–3 weeks after recovering from an URI that was caused specifically by a Streptococcus bacteria. The symptoms at onset are very similar to IgA nephropathy and include abdominal pain, hematuria, edema, and oliguria. * Henoch–Schönlein purpura (HSP) - Often considered a systemic form of IgA nephropathy, Henoch-Schönlein purpura (HSP) is a systemic small-vessel vasculitis that is characterized by deposition of IgA antibody immune complexes in different key areas throughout the body. Most often, the condition presents in children with palpable purpura, abdominal pain, and arthritis. When the kidneys are affected, the IgA immune complexes deposit in the glomerulus very similarly to IgA nephropathy and will present in a similar way. * Hemolytic uremic syndrome - Most cases occur immediately following infectious diarrhea caused by a specific type of E. coli (O157:H7). The bacteria produces a toxin that causes widespread inflammation and numerous blood clots in small blood vessels (thrombotic microangiopathy). When the inflammation reaches the kidney, or the by-products of systemic inflammation build up in the kidney, the patient will begin showing signs of<unk>  or potentially acute kidney failure (elevated creatinine, BUN, etc.). Adults * Goodpasture syndrome - This is a rare autoimmune disease where autoantibodies are produced that target the glomerular basement membrane in both the lungs and the kidneys. The damage to the basement membrane causes bleeding, and the disease often presents in patients as hematuria and haemoptysis (coughing up blood). If not treated promptly with plasmapharesis to remove the autoantibodies, it can lead to permanent damage in the lungs/kidneys. * Systemic Lupus Erythematosus (SLE) - Better known as simply "Lupus", this autoimmune disease can affect nearly every major system in the human body and the kidneys are no exception. Autoantibodies produced in SLE can form immune complexes that deposit along the glomerular basement membrane and cause glomerular inflammation which leads to a<unk> . * Rapidly progressive glomerulonephritis - This is a syndrome of the kidney that is characterized by rapid loss of kidney function (usually >50% decline in glomerular filtration rate (GFR) within 3 months) with glomerular crescent formation frequently seen on kidney biopsy. Without treatment, it will quickly lead to kidney failure and potentially death within months. This syndrome has numerous underlying causes that can also cause<unk> , so this may be more of an association than a cause. * Infective endocarditis - Infection that affects the inner lining of the heart (endocardium) and can potentially cause a thrombus to form on one or more heart valves and, if left untreated, can cause septic emboli that can have many systemic effects, including deposition into the glomerulus, causing glomerulonephritis and<unk> . * Cryoglobulinemia - Antibodies that are sensitive to the cold can become activated in cold conditions and cause an increase in blood viscosity (hyperviscosity syndrome) as well as forming immune complexes that can deposit in the small blood vessels and can cause<unk>  when this occurs in the kidneys. * Membranoproliferative glomerulonephritis (MPGN) - Another type of glomerulonephritis that is caused primarily by immune complex deposition in the glomerular mesangium and glomerular basement membrane thickening, which activates the complement cascade and damages the glomerulus. This damage leads to inflammation in the glomerulus and can present with a<unk> . * Other ANCA small-vessel vasculitides - The conditions included in this category are eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, and granulomatosis with polyangiitis.
Nephritic syndrome
Nephrotic syndrome  Nephrotic syndrome  1
Papillorenal syndrome
Culture-bound syndrome
Hepatorenal syndrome
Conorenal syndrome
Emmonsiosis
Cardiorenal syndrome