Loin Pain Hematuria Syndrome ", aka "LPHS, is the combination of debilitating unilateral or bilateral flank pain and microscopic or macroscopic amounts of blood in the urine that is otherwise unexplained.

Loin pain-hematuria syndrome (LPHS) is a poorly defined disorder characterized by recurrent or persistent loin (flank) pain and hematuria that appears to represent glomerular bleeding. Most patients present with both manifestations, but some present with loin pain or hematuria alone. Pain episodes are rarely associated with low-grade fever and dysuria, but urinary tract infection is not present. The major causes of flank pain and hematuria, such as nephrolithiasis and blood clot, are typically not present. Renal arteriography may suggest focally impaired cortical perfusion, while renal biopsy may show interstitial fibrosis and arterial sclerosis.

The pain is typically severe, and narcotic therapy is often prescribed as a way to manage chronic pain. Sleep can be difficult because the supine position increases pressure on the flank. The onset of pain is often associated with nausea and vomiting, making pain management by oral opiates complicated.

Nephroptosis is asymptomatic in most patients. However, nephroptosis can be characterized by violent attacks of colicky flank pain, nausea, chills, hypertension, hematuria and proteinuria. Patients with symptomatic nephroptosis often complain of sharp pains that radiate into the groin. Many patients also suggest a weighing feeling on the abdomen. Pain is typically relieved by lying down ( flank pain on standing that is relieved on lying down, the probable cause to pain is that movement of the kidney causes intermittent renal tract obstruction ). The attack of colic pain is called 'Dietl's crisis' or 'renal paroxysm'.

A thin glomerular basement membrane, as in thin basement membrane disease, is proposed to be the characteristic finding on renal biopsy, but not part of the syndrome definition.

Most patients with thin basement membrane disease are incidentally discovered to have microscopic hematuria on urinalysis. The blood pressure, kidney function, and the urinary protein excretion are usually normal. Mild proteinuria (less than 1.5 g/day) and hypertension are seen in a small minority of patients. Frank hematuria and loin pain should prompt a search for another cause, such as kidney stones or loin pain-hematuria syndrome. Also, there are no systemic manifestations, so presence of hearing impairment or visual impairment should prompt a search for hereditary nephritis such as Alport syndrome.

Visible hematuria causes brown or red discoloration of the urine that is visible to the naked eye. It can be painful or painless.

The most worrisome cause of painless, visible blood in the urine is kidney or bladder cancer, especially in a person wth risk factors such as male sex, age over 35, history of smoking, chronic bladder inflammation, and occupational exposures (to aromatic amines and aniline dyes) Between 80-90% of people with bladder cancer initially presented with visible hematuria.

Other causes include

- Exercise-induced hematuria–occurs in up to 30% of long distance runners and often resolves a few days after running cessation

Thin basement membrane disease must be differentiated from the other two common causes of glomerular hematuria, IgA nephropathy and Alport syndrome. The history and presentation are helpful in this regard:

- In Alport syndrome, there is often a family history of kidney failure, which may be associated with hearing impairment. Also, males tend to be more affected as Alport syndrome is X-linked in most cases.

- In IgA nephropathy, episodes of frank hematuria are more common, and a family history is less common.

A kidney biopsy is the only way to diagnose thin basement membrane disease. It reveals thinning of the glomerular basement membrane from the normal 300 to 400 nanometers (nm) to 150 to 250 nm. However, a biopsy is rarely done in cases where the patient has isolated microscopic hematuria, normal kidney function, and no proteinuria. The prognosis is excellent in this setting unless the clinical manifestations progress, as occurs in most males and some females with Alport syndrome and many patients with IgA nephropathy.

The histopathology is characterized by interstitial fibrosis, tubular atrophy,

fibrotic intimal thickening of arteries and glomerulosclerosis.

CAN is characterized by a gradual decline in kidney function and, typically, accompanied by high blood pressure and hematuria.

Nephroptosis (also called floating kidney or renal ptosis) is an abnormal condition in which the kidney drops down into the pelvis when the patient stands up. It is more common in women than in men. It has been one of the most controversial conditions among doctors in both its diagnosis and its treatments.

The classic presentation (in 40–50% of the cases) is episodic hematuria, which usually starts within a day or two of a non-specific upper respiratory tract infection (hence "synpharyngitic"), as opposed to post-streptococcal glomerulonephritis, which occurs some time (weeks) after initial infection. Less commonly gastrointestinal or urinary infection can be the inciting agent. All of these infections have in common the activation of mucosal defenses and hence IgA antibody production. Groin pain can also occur. The gross hematuria resolves after a few days, though microscopic hematuria may persist. These episodes occur on an irregular basis every few months and in most patients eventually subsides, although it can take many years. Renal function usually remains normal, though rarely, acute kidney failure may occur (see below). This presentation is more common in younger adults.

A smaller proportion (20-30%), usually the older population, have microscopic hematuria and proteinuria (less than 2 gram/day). These patients may not have any symptoms and are only clinically found if a physician decides to take a urine sample. Hence, the disease is more commonly diagnosed in situations where screening of urine is compulsory (e.g., schoolchildren in Japan).

Very rarely (5% each), the presenting history is:

- Nephrotic syndrome (3-3.5 grams of protein loss in the urine, associated with a poorer prognosis)

- Acute kidney failure (either as a complication of the frank hematuria, when it usually recovers, or due to rapidly progressive glomerulonephritis which often leads to chronic kidney failure)

- Chronic kidney failure (no previous symptoms, presents with anemia, hypertension and other symptoms of kidney failure, in people who probably had longstanding undetected microscopic hematuria and/or proteinuria)

A variety of systemic diseases are associated with IgA nephropathy such as liver failure, celiac disease, rheumatoid arthritis, reactive arthritis, ankylosing spondylitis and HIV. Diagnosis of IgA nephropathy and a search for any associated disease occasionally reveals such an underlying serious systemic disease. Occasionally, there are simultaneous symptoms of Henoch–Schönlein purpura; see below for more details on the association. Some HLA alleles have been suspected along with complement phenotypes as being genetic factors.

The signs and symptoms of hydronephrosis depend upon whether the obstruction is acute or chronic, partial or complete, unilateral or bilateral. Hydronephrosis that occurs acutely with sudden onset (as caused by a kidney stone) can cause intense pain in the flank area (between the hips and ribs). Historically, this type of pain has been described as "Dietl's crisis". Conversely, hydronephrosis that develops gradually will generally cause either attacks of a dull discomfort or no pain. Nausea and vomiting may also occur. An obstruction that occurs at the urethra or bladder outlet can cause pain and pressure resulting from distension of the bladder. Blocking the flow of urine will commonly result in urinary tract infections which can lead to the development of additional stones, fever, and blood or pus in the urine. If complete obstruction occurs, kidney failure may follow.

Blood tests may show impaired kidney function (elevated urea or creatinine) or electrolyte imbalances such as hyponatremia or hyperchloremic metabolic acidosis. Urinalysis may indicate an elevated pH due to the secondary destruction of nephrons within the affected kidney. Physical examination may detect a palpable abdominal or flank mass caused by the enlarged kidney.

Minimal change disease is characterised as a cause of nephrotic syndrome without visible changes in the glomerulus on microscopy. Minimal change disease typically presents with edema, an increase in proteins passed from urine and decrease in blood protein levels, and an increase in circulating lipids (i.e., nephrotic syndrome) and is the most common cause of the nephrotic syndrome in children. Although no changes may be visible by light microscopy, changes on electron microscopy within the glomerules may show a fusion of the foot processes of the podocytes (cells lining the basement membrane of the capillaries of glomerulus). It is typically managed with corticosteroids and does not progress to chronic kidney disease.

Cystinuria is a cause of persistent kidney stones. It is a disease involving the defective transepithelial transport of cystine and dibasic amino acids in the kidney and intestine, and is one of many causes of kidney stones. If not treated properly, the disease could cause serious damage to the kidneys and surrounding organs, and in some rare cases death. The stones may be identified by a positive nitroprusside cyanide test. The crystals are usually hexagonal, translucent, white. Upon removal, the stones may be pink or yellow in color, but later they turn to greenish due to exposure to air. Cystinuria is usually asymptomatic when no stone is formed. However, once a stone is formed, or if stone production is severe or frequent, symptoms may be present:

- Nausea/vomiting

- Dull ache or "colicky" pain

- Chronic pain

- Hematuria

- Obstructive syndromes like hydronephrosis

- Infective syndromes like pyelonephritis

Cystinurics can also experience chronic pain in one, or both, kidneys due to the scars that the jagged edges of the stones can leave or damage from multiple stone removal surgeries. This can leave a cystinuric in constant pain which often requires medical intervention, such as long-term use of analgesics or surgical procedures, including T11, T12 or T13 nerve blocks (although, these procedures are often not successful, they can provide some relief). Aside from the chronic pain, a cystinuric will often have severe breakthrough pain from passing stones. People with cystinuria pass stones monthly, weekly, or daily, and need ongoing care. Cystinurics have an increased risk for chronic kidney disease and since kidney damage or poor function is often present in cystinurics, the use of nonsteroidal anti-inflammatory drugs (NSAIDs) or over the counter (OTC) medications should be used with caution.

Cystine stones are often not visible on most x-rays, CT's, and ultrasounds. This does not mean the cystinuric doesn't have a stone. It takes a trained eye and experience to spot a cystine stone. It is not unusual for a cystinuric to pass a stone, or stones, after being released from the hospital with a CT or x-ray result of no stones in the kidneys.

Urine odor in cystinuria has a smell of rotten eggs due to the increase in cystine.

Most types of RPGN are characterized by severe and rapid loss of kidney function featuring severe hematuria (blood in the urine), red blood cell casts in the urine, and proteinuria (protein in the urine), sometimes exceeding 3 g protein/24 h, a range associated with nephrotic syndrome. Some patients also experience hypertension (high blood pressure) and edema. Severe disease is characterized by pronounced oliguria or anuria, which portends a poor prognosis.

This is characterised by forms of glomerulonephritis in which the number of cells is not changed. These forms usually result in the nephrotic syndrome. Causes include:

Hemorrhagic cystitis or Haemorrhagic cystitis is defined by lower urinary tract symptoms that include dysuria, hematuria, and hemorrhage. The disease can occur as a complication of cyclophosphamide, ifosfamide and radiation therapy. In addition to hemorrhagic cystitis, temporary hematuria can also be seen in bladder infection or in children as a result of viral infection.

Nephritis is inflammation of the kidneys and may involve the glomeruli, tubules, or interstitial tissue surrounding the glomeruli and tubules.

IgA nephropathy (IgAN), also known as IgA nephritis, Berger disease () (and variations), or synpharyngitic glomerulonephritis, is a disease of the kidney (or nephropathy); specifically it is a form of glomerulonephritis or an inflammation of the glomeruli of the kidney.

IgA nephropathy is the most common glomerulonephritis worldwide. Primary IgA nephropathy is characterized by deposition of the IgA antibody in the glomerulus. There are other diseases associated with glomerular IgA deposits, the most common being IgA vasculitis (formerly known as Henoch–Schönlein purpura [HSP]), which is considered by many to be a systemic form of IgA nephropathy. IgA vasculitis presents with a characteristic purpuric skin rash, arthritis, and abdominal pain and occurs more commonly in young adults (16–35 years old). HSP is associated with a more benign prognosis than IgA nephropathy. In IgA nephropathy there is a slow progression to chronic kidney failure in 25–30% of cases during a period of 20 years.

The prognosis of hydronephrosis is extremely variable, and depends on the condition leading to hydronephrosis, whether one (unilateral) or both (bilateral) kidneys are affected, the pre-existing kidney function, the duration of hydronephrosis (acute or chronic), and whether hydronephrosis occurred in developing or mature kidneys.

For example, unilateral hydronephrosis caused by an obstructing stone will likely resolve when the stone passes, and the likelihood of recovery is excellent. Alternately, severe bilateral prenatal hydronephrosis (such as occurs with posterior urethral valves) will likely carry a poor long-term prognosis, because obstruction while the kidneys are developing causes permanent kidney damage even if the obstruction is relieved postnatally.

Hydronephrosis can be a cause of pyonephrosis - which is a urological emergency.

Among the signs and symptoms of acute proliferative glomerulonephritis are the following:

- Hematuria:

- Oliguria

- Edema

- Hypertension

- Fever, headache, malaise, anorexia, nausea.

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).

Purpura, arthritis and abdominal pain are known as the "classic triad" of Henoch–Schönlein purpura. Purpura occur in all cases, joint pains and arthritis in 80%, and abdominal pain in 62%. Some include gastrointestinal hemorrhage as a fourth criterion; this occurs in 33% of cases, sometimes, but not necessarily always, due to intussusception. The purpura typically appear on the legs and buttocks, but may also be seen on the arms, face and trunk. The abdominal pain is colicky in character, and may be accompanied by nausea, vomiting, constipation or diarrhea. There may be blood or mucus in the stools. The joints involved tend to be the ankles, knees, and elbows, but arthritis in the hands and feet is possible; the arthritis is nonerosive and hence causes no permanent deformity. Forty percent have evidence of kidney involvement, mainly in the form of hematuria (blood in the urine), but only a quarter will have this in sufficient quantities to be noticeable without laboratory tests. Problems in other organs, such as the central nervous system (brain and spinal cord) and lungs may occur, but is much less common than in the skin, bowel and kidneys.

Of the 40% of patients who develop kidney involvement, almost all have evidence (visible or on urinalysis) of blood in the urine. More than half also have proteinuria (protein in the urine), which in one eighth is severe enough to cause nephrotic syndrome (generalised swelling due to low protein content of the blood). While abnormalities on urinalysis may continue for a long time, only 1% of all HSP patients develop chronic kidney disease. Hypertension (high blood pressure) may occur. Protein loss and high blood pressure, as well as the features on biopsy of the kidney if performed, may predict progression to advanced kidney disease. Adults are more likely than children to develop advanced kidney disease.

Cystinuria is an inherited autosomal recessive disease that is characterized by high concentrations of the amino acid cystine in the urine, leading to the formation of cystine stones in the kidneys, ureter, and bladder. It is a type of aminoaciduria.

Typically, the signs and symptoms of juvenile nephronophthisis are limited to the kidneys. They include polyuria, polydipsia, weakness, and fatigue.

Anemia, growth retardation, no hypertension.

Proteinuria and hematuria are usually absent. Polyuria is resistant to vasopressin.

When other organ systems are affected, symptoms can include situs inversus, heart abnormalities, and liver fibrosis. Juvenile nephronophthisis can also be associated with other rare disorders, including Senior–Løken syndrome and Joubert syndrome.