Transcript URINARY TRACT STRUCTURE & INFECTION

URINARY TRACT STRUCTURE
&
INFECTION
Innervation of the Urinary Tract
• Sympathetic fibers from the lower splanchnic nerves –
lumbar ganglion – kidney
• Parasympathetic vagal fibers via the coeliac plexus
• Regulation vasomotor tone, renal blood flow
• Stimulation – causes intrarenal vasoconstriction and
reduces renal blood flow,
enhances Na reabsorption
stimulates local RAAS
• Both sympathetic and parasympathetic nerve fibers
supply the ureter, vesica urinaria
Infection of the Urinary Tract
• Asymptomatic bacteriuria,
presence of bacteria in UT, absence of symptoms,
colonization from female periurethral area
• Significant bacteriuria = > 100.000 bct/ ml
in 2 voided specimens or 1 in-out catheter specimen in a
woman, or 1 voided specimen in a man
• Treatment only when risk factors for potential
complicated UTI, eg pregnancy,
Acute UTI
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Lower UTI : dysuria, frequency, urgency.
Upper UTI : infection involving the kidney
Complicated, uncomplicated
Clinical presentation in children more variable and frequently
nonspecific
Cystitis
Prostatitis, urethritis
Acute bacterial Pyelonephritis: bacterial invasion of the kidney,
clinical syndrome w/ chills and fever, flank pain,
constitutional symptoms
Chronic pyelonephritis, path ~ tubulointerstitial nephritis
caused by # of disorders: VUR, chronic obstructive uropathy,
drugs & toxins, renal medullary ds,
chronic / recurrent renal bacteriuria
Complicated infection :abnormal anatomy,
obstruction, dilatation & impaired drainage
risk of renal damage, abcess formation,septicemia
85%
50%
Urease
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Proteus mirabilis, P vulgaris, S saprophyticus
Involved in tissue adherence
Splitting urea into into CO2 & Ammonia
Urinary alkalinization
Precipitation of Mg, NH4, PO4
Stone formation, struvite
Investigation of UTI
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• Dx: Microbiological: bacterial count >10 CFU /ml
• Midstream urine collection
• Women, introitus should be cleaned with NaCl,
midstream urine is collected with the labia spread apart
• Suprapubic aspiration ( infants % children )
• Urine can be stored at 4’C for up to 48h before culture
• Infection may be present CFU 10 2 - 10 5
• Mixed culture w/ low colony counts in F ~ contamination
• Urinalysis ~first line screen, nitrates, leucocytes
+ hematuria, proteinuria
• Urine microscopy, white cell casts ~ renal parenchymal
infection
IVP
Obstructions
Prostate,
Urethral stricture
Congenital anomalies
Of urinary tract:
Reflux, urethral valves
Abscess
Displacement / lateral ectopia
Of the ureteric orifice,
Loss of valve like action
Treatment of UTI
• Most cases, uncomplicated lower UTI, 3 day course of
antibiotics, no culture needed
Trimethoprim, cephalexin, amox/clavulanate, ciprofloxacin
• Relapsing infections , 10 – 14 days
if persist / recurs, further investigation
• Prophylactic low dose antibiotics for recurrent, >3x/y UTI
• In patients w/ clear relation between infection and sexual
activity, single dose after intercourse may be effective
• Acute pyelonephritis ~ Rx in Hospital, IV fluids &
antibiotics started before culture results
• Antibiotics IV – oral , 2 weeks
• If no improvement in 48H, review AB, further investigation
(obstruction, abscess?)