Nephroblastoma Health Dictionary

Also called nephroblastoma. This is the commonest kidney tumour in infancy. It is a malignant tumour, which occurs in around one per 10,000 live births. The survival rate with modern treatment (removal of the kidney followed by radiotherapy and chemotherapy) is now around 80 per cent.... wilms’ tumour

The prevention or treatment of disease by chemical substances. The term is generally used in two senses: the use of antibacterial and other drugs to treat infections; and the administration of ANTIMETABOLITES and other drugs to treat cancer. The discovery by Paul Ehrlich in 1910 of the action of Salvarsan in treating syphilis led to the introduction of sulphonamides in 1935, followed by PENICILLIN during World War II, which revolutionised the treatment of common infections. Many ANTIBACTERIAL DRUGS have been developed since then: these include CEPHALOSPORINS, cephamycins, TETRACYCLINES, AMINOGLYCOSIDES, MACROLIDES and CLINDAMYCIN as well as antituberculous drugs such as STREPTOMYCIN and METRONIDAZOLE. Unfortunately, overuse of chemotherapeutic drugs in medicine and in animal husbandry has stimulated widespread resistance among previously susceptible pathogenic microorganisms. Chemotherapy also plays an important role in treating tropical diseases, especially MALARIA, SLEEPING SICKNESS and LEPROSY.

Recently chemotherapy has become increasingly e?ective in the treatment of cancer. Numerous drugs, generally CYTOTOXIC, are available; great care is required in their selection and to minimise side-effects. Certain tumours are highly sensitive to chemotherapy

– especially testicular tumours, LEUKAEMIA, LYMPHOMA and various tumours occurring in childhood (e.g. Wilm’s tumour – see NEPHROBLASTOMA) – and may even be cured.... chemotherapy

Diseases affecting the kidneys can be broadly classi?ed into congenital and genetic disorders; autoimmune disorders; malfunctions caused by impaired blood supply; infections; metabolic disorders; and tumours of the kidney. Outside factors may cause functional disturbances – for example, obstruction in the urinary tract preventing normal urinary ?ow may result in hydronephrosis (see below), and the CRUSH SYNDROME, which releases proteins into the blood as a result of seriously damaged muscles (rhabdomyolosis), can result in impaired kidney function. Another outside factor, medicinal drugs, can also be hazardous to the kidney. Large quantities of ANALGESICS taken over a long time damage the kidneys and acute tubular NECROSIS can result from certain antibiotics.

K

Diagram of glomerulus (Malpighian corpuscle).

Fortunately the body has two kidneys and, as most people can survive on one, there is a good ‘functional reserve’ of kidney tissue.

Symptoms Many patients with kidney disorders do not have any symptoms, even when the condition is quite advanced. However,

others 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 di?use 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.

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

Renal failure Serious kidney disease may lead to impairment or failure of the kidney’s ability to ?lter waste products from the blood and 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 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 or 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 bad 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 (see PANCREAS, DISORDERS OF) may produce a similar result. A mismatched blood transfusion can produce acute failure. Obstruction to the urine-?ow 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 chronic 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).

Familial renal disorders 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, loin or abdominal discomfort or, rarely, urinary-tract infection, hypertension and enlarged kidneys. Diagnosis is based on ultrasound examination of the abdomen. Complications include renal failure, hepatic cysts and, rarely, SUBARACHNOID HAEMORRHAGE. No speci?c 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 speci?c ANTIGEN in a part of the glomerulus. The treatment is conservative, with most patients eventually requiring dialysis or transplantation.

Acute glomerulonephritis 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 in?ammatory 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 disease is self-limiting with 90 per cent of patients spontaneously recovering. Treatment consists of control of blood pressure, reduced ?uid and salt intake, and occasional DIURETICS and ANTIBIOTICS.

Chronic glomerulonephritis is also due to immunological renal problems and is also classi?ed by taking a renal biopsy. It may be subdivided into various histological varieties as determined by renal biospy. 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 or even the cytotoxic drug CYCLOPHOSPHAMIDE or the immunosuppressant cyclosporin. Prognoses are generally satisfactory but some patients may require renal dialysis or kidney transplantation – an operation with a good success rate.

Hydronephrosis A chronic disease in which the kidney becomes greatly distended with ?uid. It is caused by obstruction to the ?ow 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 to cause hydronephrosis. Obstruction may occur at the bladder neck or in the urethra itself. Enlargement of the prostate is a common cause of bladder-neck obstruction; this would give rise to hypertrophy of the bladder muscle and both dilatation of the ureter and hydronephrosis. 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.

Impaired blood supply may be the outcome of diabetes mellitus and physiological shock, which lowers the blood pressure, also affecting the blood supply. The result can be acute tubular necrosis. POLYARTERITIS NODOSA and SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) may damage the large blood vessels in the kidney. Treatment is of the underlying condition.

Infection of the kidney is called pyelonephritis, a key predisposing factor being obstruction of urine ?ow 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) spreads up the ureters to the kidney. Symptoms are fever, malaise and backache. Antibiotics and high ?uid intake are the most e?ective treatment. Chronic pyelonephritis may start in childhood as a result of congenital deformities that permit urine to ?ow up from the bladder to the kidney (re?ux). Persistent re?ux leads to recurrent infections causing permanent damage to the kidney. Specialist investigations are usually required as possible complications include hypertension and kidney failure.

Tumours of the kidney are fortunately rare. Non-malignant ones commonly do not 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 including surgery, radiotherapy and chemotherapy is necessary. This cancer occurs mostly in adults over 40 and has a hereditary element. The prognosis is not good unless diagnosed early. In young children a rare cancer called nephroblastoma (Wilm’s tumour) can occur; treatment is with surgery, radiotherapy and chemotherapy. It may grow to a substantial size before being diagnosed.

Cystinuria 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 a very large branching calculi (staghorn calculi). Stones present as renal or ureteric pain, or as an infection. Treatment has undergone considerable change with the introduction of MINIMALLY INVASIVE SURGERY (MIS) and the destruction of stone by sound waves (LITHOTRIPSY).... kidneys, diseases of

A cancerous tumour of the kidney. Most kidney cancers originate in the kidney itself, but in rare cases cancer spreads to the kidney from another organ. There are 3 main types of kidney cancer. The most common, renal cell carcinoma, usually occurs in people over 40. Nephroblastoma (also called Wilms’ tumour) is a fast-growing tumour that mainly affects children under 5. Transitional cell carcinoma arises from cells lining the renal pelvis; it is more common in smokers or those who have taken analgesic drugs for a long time.Symptoms of kidney cancer vary. It is often symptomless in the early stages, although later there may be blood in the urine. All types require surgical removal of the kidney and sometimes also of the ureter. For nephroblastoma, surgery is followed by treatment with anticancer drugs. Kidney cancer is likely to be fatal if it has spread to other organs before treatment is started.... kidney cancer

A type of kidney cancer, also called nephroblastoma, that occurs mainly in children.... wilms’ tumour

a rare disorder consisting of the triad of *nephroblastoma (Wilms’ tumour), congenital nephropathy, and intersex disorders, resulting from mutations in the Wilm’s tumour suppressor gene (WT1). Incomplete forms exist; congenital nephropathy, with diffuse mesangial sclerosis, is the constant feature with either Wilms’ tumour or intersex disorders, usually in the form of male *pseudohermaphroditism. [P. Denys (20th century), French physician; A. Drash (20th century), British physician]... denys–drash syndrome

n. a condition in which one side of the body is larger than the other. It is often benign but can be associated with *nephroblastoma.... hemihypertrophy

an anatomical variation in kidney development whereby the lower poles of both kidneys are joined together. This usually causes no trouble but it may be associated with impaired drainage of urine from the kidney by the ureters, which cross in front of the united lower segment. The condition is associated with *Turner’s syndrome, and there is a small increase in the incidence of *nephroblastoma in those with horseshoe kidney.... horseshoe kidney

Wilms’ tumour (see nephroblastoma), aniridia, genitourinary abnormalities, and mental retardation: a condition due to a deletion of part of the short arm of chromosome 11.... wagr syndrome