Pyelonephritis Health Dictionary

An inflammation of the kidney pelvis, the interface between the urine-secreting inner surface of the kidney and the muscular ureter that drains into the bladder. It can be caused by kidney stones or an infection that has progressed up from the lower urinary tract. It alone is a serious condition...the next stage, pyelonephritis, since it involves the whole kidney, is still worse.... pyelitis

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

The clinical state which results from renal failure (see KIDNEYS, DISEASES OF). It may be due to disease of the KIDNEYS or it may be the result of pre-renal causes where a lack of circulating blood volume inadequately perfuses the kidneys. It may result from acute necrosis in the tubules of the kidney or it may result from obstruction to the out?ow of URINE.

The word uraemia means excess UREA in the blood; however, the symptoms of renal failure are not due to the abnormal amounts of urea circulating, but rather to the electrolyte disturbances (see ELECTROLYTES) and ACIDOSIS which are associated with impaired renal function. The acidosis results from a decreased ability to ?lter hydrogen ions from blood into the glomerular ?uid: the reduced production of ammonia and phosphate means fewer ions capable of combining with the hydrogen ions, so that the total acid elimination is diminished. The fall in glomerular ?ltration also leads to retention of SODIUM and water with resulting OEDEMA, and to retention of POTASSIUM resulting in HYPERKALAEMIA.

The most important causes of uraemia are the primary renal diseases of chronic glomerular nephritis (in?ammation) and chronic PYELONEPHRITIS. It may also result from MALIGNANT HYPERTENSION damaging the kidneys and amyloid disease destroying them. Analgesic abuse can cause tubular necrosis. DIABETES MELLITUS may cause a nephropathy and lead to uraemia, as may MYELOMATOSIS and SYSTEMIC LUPUS ERYTHEMATOSUS (SLE). Polycystic kidneys and renal tuberculosis account for a small proportion of cases.

Symptoms Uraemia is sometimes classed as acute – that is, those cases in which the symptoms develop in a few hours or days – and chronic, including cases in which the symptoms are less marked and last over weeks, months, or years. There is, however, no dividing line between the two, for in the chronic variety, which may be said to consist of the symptoms of chronic glomerulonephritis, an acute attack is liable to come on at any time.

Headache in the front or back of the head, accompanied often by insomnia and daytime drowsiness, is one of the most common symptoms. UNCONSCIOUSNESS of a profound type, which may be accompanied by CONVULSIONS resembling those of EPILEPSY, is the most outstanding feature of an acute attack and is a very dangerous condition.

Still another symptom, which often precedes an acute attack, is severe vomiting without apparent cause. The appetite is always poor, and the onset of diarrhoea is a serious sign.

Treatment The treatment of the chronic type of uraemia includes all the measures which should be taken by a person suffering from chronic glomerulonephritis (see under KIDNEYS, DISEASES OF). An increasing number of these patients, especially the younger ones, are treated with DIALYSIS and/or renal TRANSPLANTATION.... uraemia

The back ?ow of URINE from the URINARY BLADDER into the ureters (see URETER). The cause is defects in the VALVES which normally prevent this re?ux from occurring. If, in addition, the patient – usually a child – acquires bacteria in the bladder, the consequence may be one or more attacks of PYELONEPHRITIS caused by the infected urine gaining access to the kidney pelvis. Diagnosis is by imaging techniques. Treatment is by long-term antibiotics while awaiting spontaneous recovery. Occassionally, corrective surgery is required.... vesico-ureteric reflux

Discomfort in the abdomen. Mild abdominal pain is common and is often due to excessive alcohol

intake, eating unwisely, or an attack of diarrhoea. Pain in the lower abdomen is common during menstruation but is occasionally due to a gynaecological disorder such as endometriosis. Cystitis is a common cause of pain or discomfort in the abdomen. Bladder distension as a result of urinary obstruction may also cause abdominal pain.

Abdominal colic is pain that occurs every few minutes as one of the internal organs goes into muscular spasm in an attempt to overcome an obstruction such as a stone or an area of inflammation. The attacks of colic may become more severe and may be associated with vomiting (see abdomen, acute).

Peptic ulcer often produces recurrent gnawing pain. Other possible causes of abdominal pain are infection, such as pyelonephritis, and ischaemia (lack of blood supply), as occurs when a volvulus (twisting of the intestine) obstructs blood vessels. Tumours affecting an abdominal organ can cause pain. Abdominal pain can also result from anxiety.

For mild pain, a wrapped hot-water bottle is often effective. Pain due to peptic ulcer can be temporarily relieved by food or by taking antacid drugs. Abdominal pain that is not relieved by vomiting, persists for more than 6 hours, or is associated with sweating or fainting requires urgent medical attention. Urgent attention is also necessary if pain is accompanied by persistent vomiting, vomiting of blood, or passing of bloodstained or black faeces. Unexplained weight loss or changes in bowel habits should always be investigated.

Investigation of abdominal pain may include the use of imaging tests such as ultrasound scanning, and endoscopic examination in the form of gastroscopy, colonoscopy, or laparoscopy.... abdominal pain

Inflammation of 1 or both kidneys. Nephritis may be caused by an infection (see pyelonephritis), abnormal responses of the immune system (see glomerulonephritis), or metabolic disorders, such as gout.... nephritis

Abnormal paleness of the skin and mucous membranes, particularly noticeable in the face. Pallor is not always a symptom of disease. It may be due to a deficiency of the skin pigment melanin that may affect people who spend very little time in daylight. It is also a feature of albinism. In addition, pallor may be caused by constriction of small blood vessels in the skin, which may occur in response to shock, severe pain, injury, heavy blood loss, or fainting.Disorders that cause pallor include anaemia, pyelonephritis, kidney failure, and hypothyroidism. Lead poisoning is a rare cause.... pallor

n. the presence of bacteria in the urine (105/ml) with or without symptoms of urinary tract infection (e.g. burning or frequent urination). Asymptomatic bacteriuria is more common in women (especially during pregnancy), the elderly, and in patients with diabetes, bladder catheters, and spinal cord injuries. Unless treated with antibiotics, patients are at higher risk of kidney infections (*pyelonephritis).... bacteriuria

The kidneys are susceptible to a wide range of disorders. However, since only 1 normal kidney is needed for good health, disease is rarely life-threatening unless it affects both kidneys and is at an advanced stage.

Congenital abnormalities, such as horseshoe kidney, are fairly common and usually harmless. Serious inherited disorders include polycystic kidney disease (see kidney, polycystic), Fanconi’s syndrome, and renal tubular acidosis.

Blood vessels in the kidneys can be damaged by shock, haemolytic–uraemic syndrome, polyarteritis nodosa, diabetes mellitus, and systemic lupus erythematosus. The filtering units may be inflamed (see glomerulonephritis). Allergic reactions to drugs, prolonged treatment with analgesic drugs, and some antibiotics can damage kidney tubules. Noncancerous kidney tumours are rare, as is kidney cancer. Metabolic disorders, such as hyperuricaemia, may cause kidney stones (see calculus, urinary tract). Infection of the kidney is called pyelonephritis. Hydronephrosis is caused by urinary tract obstruction. In crush syndrome, kidney function is disrupted by proteins released into the blood from damaged muscle. Hypertension can be a cause and an effect of kidney damage.Other effects of serious damage include nephrotic syndrome and kidney failure. kidney failure A reduction in the function of the kidneys. Kidney failure can be acute or chronic. In acute kidney failure, kidney function often returns to normal once the underlying cause has been discovered and treated; in chronic kidney failure, function is usually irreversibly lost. Causes of acute kidney failure include a severe reduction in blood flow to the kidneys, as occurs in shock; an obstruction to urine flow, for example due to a bladder tumour; or certain rapidly developing types of kidney disease, such as glomerulonephritis. Chronic kidney failure can result from a disease that causes progressive damage to the kidneys, such as hypertension, longstanding obstruction to urine flow, and excessive use of analgesic drugs.

The most obvious symptom of acute kidney failure is usually oliguria (reduced volume of urine). This leads to a build-up of urea and other waste products in the blood and tissues, which may cause drowsiness, nausea, and breathlessness. Symptoms of chronic kidney failure develop more gradually and may include nausea, loss of appetite, and weakness. If acute kidney failure is due to sudden reduction in blood flow, blood volume and pressure can be brought back to normal by saline intravenous infusion or blood transfusion. Surgery may be needed to remove an obstruction in the urinary tract. Acute kidney disease may be treated with corticosteroid drugs. Treatment may also involve diuretic drugs and temporary dialysis (artificial purification of the blood). A high-carbohydrate, lowprotein diet with controlled fluid and salt intake is important for both types of kidney failure. Chronic kidney failure may progress over months or years towards end-stage kidney failure, which is life-threatening. At this stage, longterm dialysis or a kidney transplant is the only effective treatment.... kidney disorders

An infection anywhere in the urinary tract. It has differing symptoms, depending on the area affected. Urethritis causes a burning sensation when urine is being passed. Cystitis causes a frequent urge to pass urine, lower abdominal pain, haematuria, and, often, general malaise with a mild fever. Pyelonephritis causes fever and pain in the back under the ribs. Cystitis and pyelonephritis are almost always the result of a bacterial infection. Urethritis is often due to a sexually transmitted infection, such as gonorrhoea, but may have other causes. Urethral infections are more common in men. Infections further up the urinary tract are more common in women. In men, there is often a predisposing factor, such as an enlarged prostate gland (see prostate, enlarged). In women, pregnancy is a risk factor.

In both sexes, causes of urinary tract infections include stones (see calculus, urinary tract), bladder tumours, congenital abnormalities of the urinary tract, or defective bladder emptying as a result of spina bifida or a spinal injury. The risks of developing a urinary tract infection can be reduced by strict personal hygiene, drinking lots of fluids, and regularly emptying the bladder.

Urethritis can lead to the formation of a urethral stricture. Cystitis usually only causes complications if the infection spreads to the kidneys. Pyelonephritis, if it is left untreated, can lead to permanent kidney damage, septicaemia, and septic shock.

The infection is diagnosed by the examination of a urine culture. Further investigations using urography or ultrasound scanning may be necessary. Most infections of the urinary tract are treated with antibiotic drugs.... urinary tract infection

n. inflammation of the tissues around the kidney. This is usually due to spread of infection from the kidney itself (see pyelonephritis; pyonephrosis). The patient has pain in the loins, fever, and fits of shivering. Prompt treatment of the underlying renal infection is required to prevent progression to an abscess.... perinephritis

the backflow of urine from the bladder into the ureters. It is classified into primary or congenital vesicoureteric reflux, which is due to defective valves (which normally prevent reflux), or secondary, which is due to another condition (e.g. *neuropathic bladder). Infection may be conveyed to the kidneys, causing recurrent attacks of acute *pyelonephritis and scarring of the kidneys in childhood. Children with urinary infection must be investigated for reflux by *cystoscopy; if the condition does not settle with antibiotic therapy corrective surgery must be performed.... vesicoureteric reflux

n. inflammation of the vermiform *appendix. The typical presentation of acute appendicitis is central abdominal pain, which later migrates to the right lower abdomen; other symptoms include malaise, anorexia, nausea and vomiting, and even diarrhoea. Palpation of the abdomen may reveal tenderness overlying the inflamed appendix (see McBurney’s point). Unusual positions of the appendix may cause pain in different sites, leading to difficulty in diagnosis. Acute appendicitis is a surgical emergency requiring removal of the appendix (appendicectomy). Failure to do so may lead to abscess formation, perforation, peritonitis, life-threatening sepsis, and circulatory shock. Conditions that mimic appendicitis include mesenteric *lymphadenitis, terminal ileitis (see Crohn’s disease), right-sided ectopic pregnancy, a right-sided kidney stone, *pyelonephritis, and (rarely) right-sided pneumonia.... appendicitis