Page 270 - Medicine and Surgery

P1: KPE
BLUK007-06 BLUK007-Kendall May 25, 2005 18:6 Char Count= 0

266 Chapter 6: Genitourinary system

in cell membranes. E. coli also inhibits phagocytosis. Urinary stones for example, Proteus, through the pro-
Urease is produced by some organisms (e.g. Proteus), duction of urease, causes the alkalinisation of urine, so
it hydrolyses urea and increases ammonia, which fa- that phosphate, carbonate and magnesium are more
cilitates bacterial adherence. likely to precipitate to form struvite stones.
Host predisposing factors include any functional or Bacteraemia can lead to septicaemia and in vulnerable

anatomical abnormality of the urinary tract such hosts, infective endocarditis.
as urinary stasis, reflux or stones. Other important
risk factors include sexual intercourse, diabetes melli-
Investigations
tus, immunosuppression, instrumentation (including
Mid-stream urine for urinalysis (dipstick testing), mi-
catheterisation) and pregnancy.
croscopy, culture and sensitivity. A culture is regarded as
Urine itself is inhibitory to the growth of normal uri- 5

positive if >10 of a single organism per mL.
nary flora (non-haemolytic Streptococcus corynebacte-
Patients with systemic symptoms should have a blood
ria, Staphylococcus) through its pH and chemical con-
culture, FBC and differential, U&Es and creatinine to
tent.
look for dehydration and any evidence of renal impair-
ment. Further investigations are required in children
Clinical features
(see page 268), males and females with recurrent infect-
Acute cystitis typically presents with dysuria (a burning
ions.
pain on passing urine), urgency and frequency. Fever
and other systemic features are variable. Macroscopic
haematuria is not uncommon, although this should Management
prompt further investigation for any other underlying Empirical antibiotic therapy is used in symptomatic pa-
disease such as urinary stones or a bladder malignancy. tients, until culture and sensitivity results are available.
Pyelonephritis may present with few lower urinary tract Uncomplicated cystitis in a woman usually only requires
symptoms, but more commonly causes systemic upset 3daysoforal antibiotics, whereas longer courses are re-
withfever,rigors,chills,andloinpainortenderness.Pro- quired in complicated cases, e.g. those with urinary sta-
statitis causes fever, malaise and pain in the perineum sis, indwelling catheters, pyelonephritis and prostatitis.
and lower back as well as dysuria and frequency. Both Intravenous antibiotics should be used in those who are
pyelonephritis and prostatitis may be due to ascending systemically unwell or those who are vomiting.
or haematogenous infection (usually ascending). Commonlyuseddrugsincludetrimethoprim,amoxy-
UTIs in pregnancy, the elderly and those with in- cillin and co-amoxiclav (as many infections are

dwelling catheters may be asymptomatic, or may caused by β-lactamase producers). Quinolones such
present nonspecifically with fever, falls, vomiting, or as ciprofloxacin are useful as resistant E. coli and Pro-
confusion etc. teus are uncommon, but they do not adequately cover
gram-positive organisms.
Macroscopy Intravenoustherapyisoftenwithacephalosporinwith
The urine is cloudy due to the pyuria (pus cells) and or without gentamicin.
bacteriuria, and may contain visible amounts of blood Oral fluids should be encouraged where possible to pre-
(macroscopichaematuria).Sterilepyuria(puscellswith- vent dehydration and relieve symptoms. Cranberry juice
out a positive culture) may be caused by antibiotic treat- may also have a role in reducing symptoms, but has not
ment, stones, drugs such as NSAIDs and occasionally been shown to be effective in treatment or prevention of
tuberculosis. UTIs.
Recurrent UTIs may be reduced, e.g. by passing urine
Complications after intercourse, treatment of stones and in some cases
Recurrent infections which may be relapses or a re- prophylactic antibiotics. These may cause microbial re-

infection. Over time, recurrences can cause chronic sistance, and some centres advise a ‘cycling regime’, e.g.
inflammatory changes in the urinary tract (bladder, of three different antibiotics, each used for 1 month to
prostate). prevent this.