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Pyelonephritis is a kidney infection

usually caused by bacteria that have

traveled to the kidney from an infection

in the bladder.

Acute pyelonephritis is

an exudative purulent localized inflam

mation of the renal pelvis (collecting

system ) and kidney. The renal

parenchyma presents in the

interstitium abscesses

(suppurative necrosis), consisting in

purulent exudate (pus): neutrophils,fibrin, cell debris and central germ

colonies hematoxylinophils). Tubules

are damaged by exudate and may

contain neutrophil casts. In the early

stages, the glomerulus and vessels are

normal. Gross often reveals

pathognomonic radiations

of bleeding and suppuration through

the renal pelvis to the renal cortex .

Causes

Pyelonephritis most often occurs as a

result of urinary tract infection ,

particularly in the presence of

occasional or persistent backflow of

urine from the bladder into the ureters

or kidney pelvis.

Signs and symptoms

y Flank pain or back painy Severe abdominal pain (occurs

occasionally)y Fever

o Higher than 102 degreesFahrenheit

o Persists for more than 2days

y Chills with shakingy Warm skiny Flushed or reddened skiny Moist skiny Vomiting, nauseay Fatiguey General ill feelingy Painful urinationy Increased urinary frequency or

urgency

y Need to urinate at night(nocturia)

y Cloudy or abnormal urine colory Blood in the uriney Foul or strong urine odor

Diagnostic test:

Diagnosis requires a urinalysis andculture and sensitivity testing. Typicalfindings include:

y pyuria. Urine sediment revealsleukocytes singly, in clumps, andin casts and, possibly, a few redblood cells.

y significant bacteriuria. Urineculture reveals more man100,000 organisms/l of urine.

y low specific gravity andosmolality. These findings resultfrom a temporarily decreasedability to concentrate urine.

y slightly alkaline urine pH.y proteinuria, glycosuria, and

ketonuria. These conditionsoccur less frequently.

Blood tests and X-rays also help in theevaluation of acute pyelonephritis. Acomplete blood count shows anelevated white blood cell count (up to40,000/l) and an elevated neutrophilcount. The erythrocyte sedimentationrate is also elevated.

Kidney-ureter-bladder radiography may

reveal calculi, tumors, or cysts in thekidneys and the urinary tract.Excretory urography may show

asymmetrical kidneys, possiblyindicating a high frequency of infection.

TREATMENT

Treatment centers on antibiotic therapyappropriate to the specific infectingorganism after identification by urineculture and sensitivity studies. Forexample, Enterococcus requirestreatment with ampicillin, penicillin G,or vancomycin. Staphylococcusrequires penicillin G or, if the

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bacterium is resistant, a semisyntheticpenicillin such as nafcillin, or acephalosporin. Escherichia coli may betreated with sulfisoxazole, nalidixicacid, or nitrofurantoin; Proteus, withampicillin, sulfisoxazole, nalidixic acid,or a cephalosporin; and Pseudomonas,with gentamicin, tobramycin, orcarbenicillin

When the infecting organism can't beidentified, therapy usually consists of abroad-spectrum antibiotic, such asampicillin or cephalexin. Antibioticsmust be prescribed cautiously for

elderly patients because of thecombined effects of aging andpyelonephritis on renal function.Antibiotics also are used with cautionin pregnant patients. In these patients,urinary analgesics such asphenazopyridine can help relieve pain.

Symptoms may disappear after severaldays of antibiotic therapy. Althoughurine usually becomes sterile within 48to 72 hours, the course of such therapy

ranges from 10 to 14 days. Follow-uptreatment includes reculturing urine 1week after drug therapy stops and thenperiodically for the next year to detectresidual or recurring infection. Apatient with an uncomplicated infectionusually responds well to therapy anddoesn't suffer reinfection

If infection results from obstruction or

vesicoureteral reflux, antibiotics may be

less effective and surgery may be

necessary to relieve the obstruction or

correct the anomaly. A patient at high

risk for recurring urinary tract and

kidney infections - for example, a

patient with a long-term indwelling

catheter or on maintenance antibiotic

therapy - requires lengthy follow-up

care.

PREVENTION:

To help prevent pyelonephritis if you have had a previous episode

or are at risk:

y Drink several glasses of watereach day.Water discourages thegrowth of infection-causing

bacteria by flushing out yoururinary tract. This flushing alsohelps to prevent kidney stones,which can increase the risk ofpyelonephritis.

y If you are a woman, wipe fromfront to back. To prevent thespread of intestinal and skinbacteria from the rectum to theurinary tract, women shouldalways wipe toilet tissue from thefront to the back after having abowel movement or urinating.

y Decrease the spread of bacteriaduring sex.

W

omen shouldurinate after sexual intercourseto flush bacteria from thebladder. Some women who havefrequent urinary tract infectionsafter sexual activity can takeantibiotics around the time ofintercourse to prevent an

infection.

If there is a structural problem with the

urinary system, such as blockage from

a

stone, or a developmental abnormality,

then surgery can be done to restore

normal urinary function and prevent

future episodes of pyelonephritis.

Chronic...

Chronic pyelonephritis is characterized

by scarring and shrunken volume

(atrophy) of the kidneys. chronicpyelonephritis is a kidney condition

that develops over time due to damage

of kidney tissue. In adults, infection

usually plays a role, but the underlying

disorder usually involves an underlying

structural or functional abnormality in

the urinary tract that predisposes an

individual to kidney infections. It

results in decreased ability of the

kidneys to function (renal failure).

Chronic pyelonephritis is characterizedby scarring and shrunken volume(atrophy) of the kidneys. Unlike acutepyelonephritis in which there isbacterial infection of the kidney,chronic pyelonephritis is a kidney

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condition that develops over time due todamage of kidney tissue. In adults,infection usually plays a role, but theunderlying disorder usually involves anunderlying structural or functionalabnormality in the urinary tract thatpredisposes an individual to kidneyinfections. It results in decreased abilityof the kidneys to function (renalfailure).

Abnormalities that increase the risk ofchronic pyelonephritis withrepeated urinary tract

infections include diabetes, kidneystones (calculi), use of certainanalgesics, and urinary tractobstruction. Infection alone rarely leadsto chronic pyelonephritis and loss ofkidney function.

Chronic pyelonephritis can developwithout infection. Individuals with anabnormality of the junction between theureter and bladder (vesicoureteralunction) in childhood may develop

chronic pyelonephritis. Abnormality ofthe vesicoureteral junction, a congenitalcondition in which the juncturebetween the ureters and bladder isweak, allows urine to flow backwardfrom the bladder to the ureter and upinto the kidney. Severe reflux alone canlead to kidney scarring, even in theabsence of other factors known tocause kidney scarring. The scarring ofthe kidneys associated withvesicoureteral reflux is similar to that

seen with repeated infection combinedwith underlying structural abnormality.Some authorities theorize that kidneyscarring due to reflux of urine (refluxnephropathy) may be an autoimmuneprocess. Other noninfectious conditionsthat may scar the kidneys similarly tovesicoureteral reflux are long-standing high bloodpressure(hypertension) and use ofcertain analgesics.

Individuals with increased risk includethose with congenital urinary tractabnormalities, and those with recurrenturinary tract infections.

Risk: Chronic pyelonephritis affects

women more frequently than men. It is

more common in whites than blacks.

History: Symptoms reported may vary,

depending on whether or not infection

is present. Individuals without infection

may not have symptoms

(asymptomatic) until they reach the

later stages of chronic pyelonephritis

with chronic kidney failure. Symptoms

may be non-specific, including high

blood pressure (hypertension) and signsof kidney failure such as itching

(pruritus), generalized malaise, feeling

tired (lassitude), forgetfulness, easy

fatigability, nausea, and loss of sexual

drive (libido). If infection is present, the

individual may complain of symptoms

similar to those of acute pyelonephritis,

with rapid development of symptoms

over the course of a few hours or days.

Individuals may report a high fever

(101 F to 104 F [38.3 C to 40 C] or

higher) and shaking chills; pain in the

flank, particularly in the lower back on

the right side; increased frequency of

urination; pain and a burning

sensation upon urination (dysuria);

nausea and vomiting; decreased

appetite (anorexia); and general fatigue.

The urine may appear cloudy or blood-

tinged with a fishy odor. Some

individuals may note only

diffuse abdominal pain with nausea,

vomiting, and diarrhea.W

hen asked,the individual may report a history of

unexplained fevers and bed-wetting

during childhood.

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Physical exam: In the absence of acute

infection, the physical examination may

be essentially normal. With infection,

physical exam may reveal generalized

muscle tenderness and pain and

tenderness when pressure is applied to

the sides of the abdomen (flank or

costovertebral angle tenderness). Fever,

high blood pressure, and other

symptoms may be confirmed duringphysical examination.

Tests: If a urinary tract and/or kidney

infection is suspected, a sample of

urine collected in midstream should be

cultured to determine the number and

species of bacteria present. Sensitivities

(to antibiotics) will be obtained. Theurine sediment is examined for red

blood cells or pus in the urine

(hematuria or pyuria). Urinalysis may

reveal protein in the urine (proteinuria,

albuminuria) and whether the urine is

abnormally concentrated or dilute.

Laboratory testing may reveal

decreased kidney functioning, with

increased blood urea nitrogen (BUN)

and creatinine. A 24-hour urine

collection helps quantitate kidney

function. Urine and blood cultures may

reveal the presence of bacteria in the

urine or blood. An x-rayof the kidney

may reveal kidney

stones (calculi), tumors, or cysts in the

kidney or urinary tract. Kidney x-ray

using dye injection that concentrates in

the urine (intravenous pyelogram) helps

visualize the kidneys and urinary tract.

Kidneys may appear asymmetrical,

indicating severe inflammation. In some

cases, an abdominal CT scan or

renal ultrasound may be indicated,especially in individuals with an

unclear diagnosis or who have

complicated conditions. In some cases,

urine specimens may be obtained

directly from the ureter for culture

through an invasive ureteral

catheterization procedure.

If a non-infectious cause is suspected,

a kidney x-ray (intravenous pyelogram)

or renal ultrasound procedure may be

indicated. The kidneys may have an

irregular outline and appear smaller

than normal. If only one kidney is

affected, the other kidney may be larger

due to hypertrophy. An x-ray of the

kidney may reveal kidney

stones (calculi), tumors, or cysts in the

kidneys or urinary tract. Kidney

(renal) biopsy may be recommended in

some cases to rule out other potential

causes for the inflammation.

Treatment is directed at eradicating

infection if present, and at correcting

underlying causes. If a urinary tract

infection is the cause, antibiotics are

the first line of therapy. Whenever

possible, the type of bacteria causing

the infection should be identified and

antibiotics specific for that organismare then prescribed. A follow-up culture

of the urine may be obtained 1 week

after the end of drug therapy. It may be

necessary to continue long-term

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antibiotic therapy for up to 3 to 6

months.

Underlying structural abnormalities are

corrected wherever possible. Surgery

may be necessary to remove

obstruction or to repair a stricture. A

variety of surgical procedures may be

performed, depending on the

underlying cause of the obstruction orstricture. It may be necessary to repair

the pelvis of the kidney (pyeloplasty)

due to an obstruction of the

ureteropelvic junction. Kidney stones

may be removed through an open

incision or through a transurethral

approach using cystoscopy and

a stone-basketing procedure. Surgical

treatment of vesicoureteral reflux may

involve repair of congenital

abnormalities that lead to

vesicoureteral reflux as a complication,

or surgical treatment may involve a

variety of procedures designed to

correct the vesicoureteral reflux

condition itself (reimplantation of

ureters). Removal of a kidney

(nephrectomy) may be recommended in

cases in which only one kidney is

severely affected (unilateral).

Other types of medical treatment may

be necessary.M

edications may beprescribed to control hypertension. If

kidney failure has occurred,

medications, diet changes,

and dialysis may be necessary