renal infection pdf - د.عمار فاضل(urinary)

Urinary Tract

Infections

KIDNEY INFECTIONS

Dr. AMMAR FADIL

General principles

• Urinary tract infections (UTIs)



is inflammatory response of the urothelium to
bacterial invasion.



are common



affect men and women of all ages,.



The diagnosis of UTI is based on

symptomatology, urinalysis, & urine culture
findings

2\43

Definitions

• Pyuria

– is the presence of white blood cells (WBCs) in the

urine in dipstick or

10 WBC/HPF

in sediment of

centrifuged urine. occur either due to

– bacterial infection or
– sterile pyuria absence of bacteriuria carcinoma in

situ, TB infection, & stones

• Bacteriuria

– is the presence of bacteria in the urine which is

normally free of bacteria. symptomatic or
asymptomatic

Routes of infection

• Ascending route (commonest)



bacteria derived from the large

bowel, colonize the perineum,

vagina, and distal urethra.



They ascend along the urethra to the

bladder (risk is increased in

♀ as the

urethra is shorter), causing cystitis,



& from the bladder they

may

ascend, via the ureters, to involve the kidneys

(pyelonephritis

Routes of infection

• Hematogenous route

Infection of the kidney is uncommon. Occurs in

patients with Staphylococcus aureus
bacteremia & TB

Predisposing Factors

1.stasis & obstruction:

– prostatic enlargement
– vesico ureteric reflux of urine VUR
– neurogenic bladder (spinal cord injury, DM)

2. foreign body:

– catheter
– stone

3.Decreased resistance

– diabetes mellitus
–

malignancy

–

immunosuppression

4. congenital anomaly

UPJ obstruction,

APCKD.

Urinary pathogens

• Most UTIs are caused by facultative anaerobes

usually originating from the bowel flora.

“

KEEPS

”

– K lebsiella
– E . Coli (85%)
– Enterococci
– Proteus mirabilis, pseudomonas
– S .saprophyticus , S. Fecalis

UTI

• Isolated UTI

– has an interval of at least 6 months between

infections.

• Recurrent UTI

– is >2 infections in 6 months, or 3 within 12

months.

• Unresolved infection

– is failure of the initial treatment course to

eradicate bacteria from the urine.

• antimicrobial resistance,
• patient noncompliance with therapy,
• insufficient antibiotic dosing

UTI basic investigation

• Urine dipstick MSU is used as a first-line

screening.

• GUE: the observation of WBC, bacteria & RBC
• Urine culture is the gold standard for the

diagnosis of UTI.

Imaging studies are not required in most cases of UTI

Further investigation

• US:

calculi & hydronephrosis

PVR

• VCUG

vesicoureteral reflux Dx.

Further workup

is needed in



upper tract infection (fever, flank pain,

malaise, that suggest

acute pyelonephritis, a

pyonephrosis, or perinephric abscess



Pregnant patient



Unusual infecting organism (e.g.,

Proteus),

suggesting the possibility of an ??

–

Recurrent UTIs

Lower UTI

cystitis

UTI

Upper UTI

Pyelonephritis

Acute pyelonephritis

• pyelonephritis is defined as

inflammation of the kidney
and renal pelvis

• A clinical diagnosis is based

on the presence of fever, flank
pain, and tenderness. It may
affect one or both kidneys.

Symptoms



The onset is usually abrupt.



fever(38.5 to 40 C),rigor & flank pain



symptoms of

cystitis

(dysuria, frequency, urgency, suprapubic

pain) These are usually suggestive of a lower

urinary tract infection that led to the ascending

infection, which resulted in the subsequent acute

pyelonephritis



Nausea and vomiting are common.

• Renal angle

tenderness.

Physical sign

Investigation

• GUE:

increased pus cells, WBC casts, & RBC.

Bacteria are often seen.

• Urine culture & sensitivity test.
• Blood tests may show a leukocytosis.
• RFT
• U/S & KUB: to see if there is an underlying

upper tract abnormality (such a ureteric stone)

Treatment

• involves the administration of antibiotics

according to the clinical presentation and
most likely causative organism, before
culture sensitivities are available

Treatment



patients who have a fever but are not

systemically unwell, outpatient oral Rx

choice is Fluoroquinolones

ciproﬂoxacin 500 mg PO bid, or

levoﬂoxacin 750 mg PO qd)

Trimethoprim-sulfamethoxazole



If the patient is systemically unwell, admit to
hospital and start IV fluids & parenteral
antibiotics

Parenteral antibiotics

We use one of the following:

1. 3

generation cephalosporine

(

cefotaxime or ceftriaxone, ceftazidime

These are active against gram-negative bacteria. also has

activity against Pseudomonas aeruginosa.

2. I.V Fluoroquinolones (e.g., ciprofloxacin)

They exhibit good activity against

Enterobacteriaceae & P. aeruginosa

3.ampicilline & gentamycin

Parenteral antibiotics for 3 days then switch to oral for total

10-14 d

Treatment

However, if the patient does not respond
within 3 days to this regimen of IV antibiotics
(conﬁrmed on sensitivities), a CT urogram
is essential.

• The lack of response to treatment suggests the

possibility of a

pyonephrosis

(i.e., pus in the

kidney, which, like any abscess, will only
respond to drainage)

Pyelonephritis of pregnancy



usually occurs

during 3

trimester

when hydronephrosis & stasis in the

urinary tract are most pronounced .



Complications:

abortion or premature birth.



Rx:

Pregnant women should be

hospitalized and treated initially with

parenteral antimicrobial agents 3

generation cephalosporine

Urinary infection in childhood

• It is one of the most common bacterial diseases in

children;

• is important to recognise because it may damage the

growing kidney.

• symptoms are often non-specific but the child

may pass cloudy or offensive urine.

Pain or screaming on micturition

child fails to thrive

unexplained pyrexia.

The older child may complain of loin pain

VUR

• VUR of urine is detectable in about 35% of

children with recurrent UTI

•

Up to 50% of children with UTI have an underlying anatomical abnormality (e.g.

reflux or obstruction).

Pathogenesis of

VUR

• VUR

retrograde flow of urine from the bladder into the upper

urinary tract.

• The ureter passes obliquely through the bladder wall (1–2

cm), where it is supported by muscular attachments that
prevent urine reflux during bladder filling and voiding.

• Reflux occurs when the intramural length of ureter

is too short .The degree of reflux is graded I

–V.

Complications VUR

• Recurrent UTI
• reflux nephropathy with hypertension &

progressive renal failure.

– reflux nephropathy is the most common cause

of end-stage renal failure in children

Dx VUR

VCUG to diagnose &
grade reflux

– Urinalysis

Urine culture a pure

growth of more than 10

organisms/ml.

– ultrasound scan

Treatment

• Medical treatment

Continuous antibiotic prophylaxis: e.g trimethoprim 1

–2

mg/kg/day, usually as a single night-time dose.

Endoscopic

• subureteric injections

(Bulking agent) e.g Deflux

• Surgery

Surgical reimplantation of the ureters is

reserved for those in whom

conservative measures fail.

Chronic pyelonephritis



Refers to the small, contracted, atrophic kidney
that has been produced by bacterial infection,



It can be a radiological or pathological diagnosis.



chronic pyelonephritis is the end result of
longstanding reflux or obstruction. These
processes damage the kidneys, leading to
scarring.

Clinical Presentation

•

Most of the changes of chronic
pyelonephritis seem to occur in infancy,
because the growing kidney is most

susceptible to scarring

•

in adults renal damage is rare in non
obstructive UTIs

•

There are no symptoms of chronic
pyelonephritis until it produces renal
insufficiency, and then the symptoms are similar
to chronic renal failure.

Pyonephrosis

• This is an infected hydronephrosis, the

infection being severe enough to cause
accumulation of pus with the renal pelvis
and calyces of the kidney.

• causes include ureteric obstruction by

stone and PUJ obstruction.

Pyonephrosis

• Clinical presentation: patients very ill ,high fever

,flank pain ,chills ,renal tenderness, Previous
history of urinary calculi, infection or surgery.

• Management antibiotics and drainage of

infected pelvis ( ureteral catheter, nephrostomy)

perinephric abscess

• develops as a

consequence of extension
of infection outside the
parenchyma of the
kidney.

Patients with pyonephrosis,

particularly when a
calculus is present in the
kidney, are susceptible to
perinephric abscess
formation.

Perinephric abscess

These patients are often diabetic, &

associated conditions such as an
obstructing ureteric calculus.

treatment is surgical drainage

Renal tuberculosis

The kidney is among the most common sites for
extrapulmonary tuberculosis.

Renal tuberculosis (TB)

is caused by Mycobacterium tuberculosis.

arises from haematogenous spread

from a distant focus which is impossible to identify.

are usually confined to one kidney.

the latent period between exposure &

reactivation of disease is 10- 40 yr

Kidney

Hematogenous spread causes granuloma
formation in the renal cortex, associated with
caseous necrosis of the renal papillae and
deformity of the calyces, leading to release of
bacilli into the urine. This is followed by
healing fibrosis and calcification, which
causes destruction of renal architecture and
autonephrectomy.

Ureters

• Seeding of the urine may also result in

involvement of the bladder and male
genital organs

• TB Spread is directly from the kidney and

can result in stricture formation.

• Bladder Infection is usually secondary to

renal infection. Disease progression
causes fibrosis and contraction (resulting
in a small capacity ‘thimble’ bladder),

• Renal tuberculosis is often associated

with tuberculosis of the bladder and
typical tuberculous granulomas may be
visible in the bladder wall

Clinical features

• Because of the slow progression and variable

course of the disease, there is no classic
presentation.

• Renal symptoms gross hematuria; dull flank

discomfort; and ureteral colic secondary to
passage of clots, debris, or calculi.

• Constitutional complaints such as fevers, chills, night sweats,

weight loss, and malaise are uncommon.

• It is only when the bladder is involved

that the patients become severely
symptomatic.

• Frequency is the most common

presenting symptom and is often
progressive and occurs during the day
and at night. Pain, urgency, and dysuria
are also common.

physical examination

• A chronic draining fistula tract from

previous renal surgery.

• Patients with chronic epididymitis

unresponsive to therapy should also be
evaluated.

Investigation

• Urine: At least 3 early morning urines . A

typical finding is sterile pyuria (leukocytes,
but no growth). Ziehl

–Neelsen staining will

identify these acid- & alcohol fast bacilli
(cultured on Lowenstein

–Jensen medium).

pyuria C\S no growth of bacteria ?

investigations

• KUB: Findings include renal

calcification (cement kidney)

• IVU: irregular calyces,

hydronephrosis

caused by stricture of the

ureter

• CXR and sputum
• Tuberculin skin test

• Cystoscopy: bladder studded with

granulomas which cluster
particularly around the ureteric

orifices

Treatment

• Medical Rx is with 6 months of isoniazid,

rifampicin, and pyrazinamide

• If the kidney has no function it is best to

perform a nephroureterectomy .

Investigation

• Urinary sediment

may show pus cells,
proteinuria.

• IVP: irregularity of

the kidney outlines
with blunting and
dilation of calyces

Management

• treating infection, if present; and

monitoring and preserving renal
function.