urinary tract structure

7/28/2019 Urinary Tract Structure

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URINARY TRACT STRUCTURE

&

INFECTION


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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


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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/ mlin 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,


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Acute UTI

Lower UTI : dysuria, frequency, urgency. Upper UTI : infection involving the kidney

Complicated, uncomplicated

Clinical presentation in children more variable and frequentlynonspecific

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


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85% 50%


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Urease

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


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Investigation of UTI

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 4C for up to 48h before culture

Infection may be present CFU 10 - 10

Mixed culture w/ low colony counts in F ~ contamination

Urinalysis ~first line screen, nitrates, leucocytes

+ hematuria, proteinuria

Urine microscopy, white cell casts ~ renal parenchymalinfection

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Obstructions

Prostate,

Urethral stricture

Congenital anomalies

Of urinary tract:

Reflux, urethral valves

IVP

Abscess


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Displacement / lateral ectopia

Of the ureteric orifice,

Loss of valve like action


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Treatment of UTI

Most cases, uncomplicated lower UTI, 3 day course ofantibiotics, 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 sexualactivity, 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?)

urinary tract structure

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