Post on 07-Apr-2018
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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