Many patients with kidney disorders do not have any symptoms, even when the condition is quite advanced. Others may experience loin pain associated with obstruction (renal colic) or due to infection; fevers; swelling (oedema), usually of the legs but occasionally including the face and arms; blood in the urine (haematuria); and excess quantities of urine (polyuria), including at night (nocturia), due to failure of normal mechanisms in the kidney for concentrating urine. Patients with chronic renal failure often have very diffuse symptoms, including nausea and vomiting; tiredness due to ANAEMIA; shortness of breath; skin irritation; pins and needles (paraesthesia) due to damage of the peripheral nerves (peripheral neuropathy); and eventually (rarely seen nowadays) clouding of consciousness and death.

of kidney disease include loin tenderness, enlarged kidneys, signs of fluid retention, high blood pressure and, in patients with end-stage renal failure, pallor, pigmentation and a variety of neurological signs including absent reflexes, reduced sensation, and a coarse flapping tremor (asterixis) due to severe disturbance of the body's normal metabolism.

Serious kidney disease may lead to impairment or failure of the kidney's ability to filter waste products from the blood and to excrete them in the urine – a process that controls the body's water and salt balance and helps to maintain a stable blood pressure. Failure of this process causes URAEMIA – an increase, in the blood, of urea and other metabolic waste products – as well as other metabolic upsets in the blood and tissues, all of which produce varying symptoms. Failure can be sudden (acute), or can develop more slowly (chronic). In the former, function usually returns to normal once the underlying cause has been treated. Chronic failure, however, usually irreparably reduces or stops normal function.

Acute failure commonly results from physiological shock following a severe injury or major illness. Serious bleeding or burns can reduce blood volume and pressure to the point where blood-supply to the kidney is greatly reduced. Acute myocardial infarction (see HEART, DISEASES OF) or PANCREATITIS may produce a similar result. A mismatched blood transfusion can produce acute failure. Obstruction to the urine-flow by a stone (calculus) in the urinary tract, a bladder tumour or an enlarged prostate can also cause acute renal failure, as can glomerulonephritis (see below) and the haemolytic-uraemia syndrome.

HYPERTENSION, DIABETES MELLITUS, polycystic kidney disease (see below) or AMYLOIDOSIS are among conditions that cause the more slowly progressing renal failure. Others include stone, tumour, prostatic enlargement and overuse of analgesic drugs. Chronic failure may eventually lead to end-stage renal failure, a life-threatening situation that will need DIALYSIS or a renal transplant (see TRANSPLANTATION).

include autosomal dominant inherited polycystic kidney disease and sex-linked familial nephropathy. Polycystic kidney disease is an important cause of renal failure in the UK. Patients, usually aged 30–50, present with HAEMATURIA, HYPERTENSION, loin or abdominal discomfort or, rarely, urinary-tract infection, and enlarged kidneys. Diagnosis is based on ultrasound examination of the abdomen. Complications include renal failure, hepatic cysts and, rarely, SUBARACHNOID HAEMORRHAGE. No specific treatment is available. Familial nephropathy occurs more often in boys than in girls, and commonly presents as Alport's syndrome (familial nephritis with nerve DEAFNESS) with PROTEINURIA, haematuria, progressing to renal failure and deafness. The cause of the disease lies in an absence of a specific ANTIGEN in a part of the glomerulus. The treatment is conservative, with most patients eventually requiring dialysis or transplantation.

is an immune-complex disorder due to entrapment within glomerular capillaries of ANTIGEN (usually derived from B haemolytic streptococci – see STREPTOCOCCUS) antibody complexes initiating an acute inflammatory response (see IMMUNITY). The disease affects children and young adults, and classically presents with a sore throat followed two weeks later by a fall in urine output (oliguria), haematuria, hypertension and mildly abnormal renal function. The large majority recover spontaneously, but about 10 per cent may progress to chronic renal impairment. Treatment consists of control of blood pressure, reduced fluid and salt intake, and occasional DIURETICS and ANTIBIOTICS.

is also due to immunological renal problems. It is diagnosed by renal biopsy, and the disease may thus be subdivided into various types according to appearance on HISTOLOGY. Proteinuria of various degrees is present in all these conditions, but the clinical presentations vary, as do their treatments. Some resolve spontaneously; others are treated with steroids, the cytotoxic drug CYCLOPHOSPHAMIDE or immunosuppressant ciclosporin. Many make a full recovery but some patients may eventually require renal dialysis or kidney transplantation.

A chronic disease in which the kidney becomes greatly distended with fluid. It is caused by obstruction to the flow of urine at the pelvi-ureteric junction (see KIDNEYS – Structure). If the ureter is obstructed, the ureter proximal to the obstruction will dilate and pressure will be transmitted back to the kidney and cause hydronephrosis. Obstruction may occur at the bladder neck or in the urethra itself. Enlargement of the PROSTATE GLAND is a common cause of bladder-neck obstruction, and causes hypertrophy of the bladder muscle; both dilatation of the ureter and hydronephrosis may result. If the obstruction is not relieved, progressive destruction of renal tissue will occur. As a result of the stagnation of the urine, infection is probable and CYSTITIS and PYELONEPHRITIS may occur.

may be the outcome of diabetes mellitus and physiological shock, which lowers the blood pressure and affects the blood supply to the kidneys. The result can be acute tubular necrosis. POLYARTERITIS NODOSA and SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) may damage the large blood vessels of the kidney; treatment is of the underlying condition.

of the kidney is called pyelonephritis, a frequent predisposing factor being obstruction of urine flow through the urinary tract. This causes stagnation, and provides a fertile ground for bacterial growth. Acute pyelonephritis is more common in women, especially during pregnancy when bladder infection (CYSTITIS) may spread up the ureters to the kidney. Symptoms are fever, malaise and backache. Antibiotics and high fluid intake are the most effective treatment. Chronic pyelonephritis may start in childhood as a result of congenital deformities that permit urine to flow up from the bladder to the kidney (reflux). Persistent reflux leads to recurrent infections and causes permanent damage to the kidney. Specialist investigations are usually required, as possible complications include hypertension and kidney failure.

are fortunately rare. Non-malignant ones seldom cause symptoms, and even malignant tumours (renal cell carcinoma) may be asymptomatic for many years. As soon as symptoms appear – haematuria, back pain, nausea, malaise, sometimes secondary growths in the lungs, bones or liver, and weight loss – urgent treatment which may involve any combination of surgery, radiotherapy or chemotherapy is necessary.

is an inherited metabolic defect in the renal tubular reabsorption of cystine, ornithine, lysine and arginine. Cystine precipitates in an alkaline urine to form cystine stones. Triple phosphate stones are associated with infection, and may develop into very large branching calculi (staghorn calculi). Stones present as renal or ureteric pain, or as an infection. Treatment is with MINIMALLY INVASIVE SURGERY (MIS) and the destruction of stones by sound waves (LITHOTRIPSY).