Urinary Tract Infection Flashcards
1
Q
define UTI
A
presence of micro-organisms in the urinary tract that are causing clinical infection
2
Q
what does lower UTI denote
A
infection confined to the bladder - cystitis
3
Q
complicated UTI
A
UTI complicated by systemic symptoms (eg fever, loin pain, malaise) or urinary structural abnormality/stones
4
Q
bacteriuria
A
bacteria present in the urine
doesnt always mean there is a n infection
5
Q
in which patients is there commonly bacteriuria without infection
A
elderly and those with catheters
6
Q
UTI in men
A
culture as this is uncommon and there is often an underlying cause
7
Q
is urine sterile?
A
- bladder urine normally is
- urine passed via the urethra will be contaminated with bacteria from the perineum or lower urethra
8
Q
why is MSU used
A
first pass is most likely to be contaminated
9
Q
suprapubic aspiration and straight (in/out) catheter urine sample
A
achieve a clean sample, however are not practical
10
Q
Boricon container
A
- for MSU
- red lid
- contains boric acid which is a preservative to stop the bacteria multiplying so works for around 24 hours
- Is often used in GPs
11
Q
sterile universal container
A
- for MSU
- white lid
- must reach lab within 2 hours of collection
12
Q
what do you do with a sample you receive that has expired (over 2 hours in white, over 24 in red top)
A
discard it
13
Q
which presumption is made when analysing a MSU sample
A
that the sample has been taken properly
14
Q
directions for collecting a MSU
A
- Label container
- Give a suitable wide mouthed sterile (foil) bowl to the patient, especially important in females
- First urine passed into toilet, and mid-stream part collected
- Urine is transferred from bowl to appropriate laboratory container
15
Q
should the perineum/urethral meatus be washed with sterile sample before taking MSU
A
controversiale evidence
16
Q
who might not be able to give a MSU
A
those with mobility/cognitive issues or those who are very young
17
Q
who is a clean catch urine sample used in
A
children, those with cognitive impairemnet or physical restriction
18
Q
which patients is a bag specimen of urine used in
A
- babies
- the bag is attached to the perineum, so often contaminated with bowel flora
19
Q
when is dipstick of good use
A
- in the community setting
- it is only really effective as a negative predictor (eg rule out infection)
- often used in young women who present at the GP with cystitis
20
Q
leukocyte esterase on dipstick
A
- indicates the presence of WBC in the urine
- esterase is an enzyme produced by WBC
21
Q
nitrites on dipstick
A
- indicate the presence of certain bacteria in the urine, these convert endogenous nitrates to nitrites
- mainly coliforms
22
Q
which bacteria dont produce nitrite positiive dipstick
A
- pseudomonas
- enterococcus
- staphylococcus
23
Q
in which 2 groups of patients should you definitely not dipstick urine
A
- elderly
- catheter specimens
contaminated !!
24
Q
what is microscopy of urine used for
A
- looks for the presence of polymorphs (pus cells), bacteria and red cells in urine
- rarely used
25
what is a culture used for
to detect significant bacteriuria
26
Kass's criteria for urine culture
counts number of colonies to determine the likelihood of a UTI
* **\>105 organisms / ml:** significant =probable UTI
* \<103 organisms / ml: not significant bacteriuria
* 104 organisms / ml:? contaminated ?infection - repeat specimen
27
which patient group does Kass's criteria apply to
those of child bearing age
28
what is a genuine UTI in a non-catheterised usually caused by
* pure growth - single organism \>105 orgs/ml
29
mixed growth
* (≥2 organisms)
* even if \>105 is probably not significant
30
what is the distribution like of infection in the kidney
patchy
31
pathogenesis of pyelonephritis
* most commonly an ascending infection from a lower UTI
* present in conjunction with cystitis
* bacteria from bowel, perineal skin of lower end of urethra
* blood borne spread
* rarely occurs in septicemia, infective endocarditis or post surgery
32
which organisms are often implicated in a pyelonephritis from blood borne spread
S aureus
also E coli
33
what is the most common organism in a UTI
E coli
34
organisms implicated in UTI
* **E coli**
* Other aerobic Gram negatives e.g. *Enterobacteriaceae*, *Pseudomonas**, Proteus*
* *Enterococcus (**faecalis** and faecium)*
35
where does E coli reside in cells
in the LPS layer of gram negatives and activates the immune response from here
36
give 2 reasons as to why E coli is the most common cause of UTI
* most common aerobe in the bowel
* has fimbriae which allow it to ascend up the urinary tract
37
what precautions must be taken for a E coli infection
no extra needed - standard gloves and apron
38
infection with which organism causes the development of renal stones
* proteus
* produces urease which breaks down urea to form ammonia, which increases urinary pH
* this causes precipitation of salts
* - renal stones
39
which type of stones does proteus cause
* struvite stones- triple phosphate stones
* cause staghorn calculi
40
describe the culture of proteus
swarming
41
what is the odour of proteus culture described as
burnt chocolate
42
what is pseudomonas assoicated with
catheters and instrumentation
43
which ABx cover pseudomonas
resistant to most oral ABx, except ciprofloxacin
44
what gram positives cause UTI
* enterococcus
* enterococcus faecalis is the main concern
* and also Enterococcus faecium
* staph saphrophyticus
45
in which context are UTI infected with Enterococcus usually seen
hospital acquried infections
46
what type of coagulase is *Staphylococcus saphrophyticus*
negative
47
who is infections with *Staphylococcus saphrophyticus* usually seen in
women of child bearing age
48
name 2 anatomical reasons as to why females are more likely to get UTI
* shorter, wider urethra
* proximity of urethra to anus
49
how does pregnancy increase risk of UTI
* ureteric dilatation due to hormones causes a slower flow of urine - inc risk of infection
* weight of uterus on bladder
50
vesico-ureteric reflux
normally the ureters prevent reflux:
* enter the bladder in an infero-medial direction
* the last part is detrusor muscle, which contracts with the bladder
1y or 2y problems with this
* 2y - bladder outlet obstruction can increase pressure in the bladder and distort the valve
51
congenital causes of vesico ureteral reflux
* In congenital cases, the ureters are displaced laterally, entering the bladder in a more perpendicular fashion than at an angle, therefore the intramural course of the ureter is shortened.
52
how does diabetes increase risk of UTI
* poor circulation dampens down inflammatory response
* high glucose levels in urine
* bladder doesnt empty as well as it should
53
other factors that increase risk of UTI
* urinary tract obstruction
* sex
* indwelling catheter
* incomplete bladder emptying
* thrush
54
name 4 specific risk factors for pyelonephritis
* HIV/AIDS
* diabetes
* IS
* congenital/acquired urodynamic abnormalities
55
clinical signs of cystitis
* Urinary frequency
* Dysuria
* Nocturia
* Suprapubic pain
* Haematuria is not a usual symptom
56
clinical signs of pyelonephritis
* Fever, loin pain and rigors suggest involvement of the upper urinary tract. The patient will be significantly more unwell
* Vomiting, tachycardia
* Leukocytosis – increased WBC in blood
57
ideal ABx for treatment of lower UTI
* excreted in urine in high concentration
* oral
* inexpensive
* few side effects
58
how long are ABx required for to treat uncomplicated lower UTI in women
3 days
59
how long are ABx required to treat a lower UTI in males
7 days
60
what is an alternative to ABx that can be used in those with cystitis that may be just as good
anti inflammatories
61
what is abacterial cystitis also known as
urethral syndrome
62
abacterial cystitis
* the patient has symptoms of a UTI, there are pus cells present in the urine but there is not signifcant growth on culture
63
reason for abacterial cystitis
* early phase of UTI
* urethral trauma - honey moon cystitis
* urethritis caused by STI
64
what can be done to the urine to provide symptomatic relief of UTI symptoms
alkalinze it
65
asymptomatic bacteriuria
* Significant bacteriuria (\>105 orgs/ml) but the patient is asymptomatic
* there are no pus cells in the urine
66
are ABx required for *Asymptomatic Bacteriuria*
* usually no!
* it may recur even if ABx treatment is given
* give in pregnancy
67
when are pregnant women screened for bacteriuria
1st antenatal visit
68
Asymptomatic Bacteriuria in pregnancy
treated with ABx, as if left untreated there is a risk of pyelonephritis
69
risk of pyelonephritis in pregnancy
* intra uterine growth retardation
* premature labour
70
which ABx are given for *Asymptomatic Bacteriuria* in pregnancy (GP setting)
* trimethoprim is contraindicated in 1 st trimester
* nitrofurantoin is contraindicated in 3rd trimester
* cefalexin may be used!
71
why is Trimethoprim contraindicated in 1st trimester
inhibits folic acid synthesis
72
why is Nitrofurantoin contraindicated in 3rd trimester
can cause neonatal haemolysis
73
does a catheter increase the risk of UTI
yes, it is the most common cause hospital acquired infection
74
when should you give ABx to someone with a catheter
* \>105 orgs/ml AND supporting evidence of UTI
* as the longer the catheter is in situ, the more likely it is to be colonised with bacteria
75
what will giving unnecessary ABx in someone with a catheter cause
catheteter to become colonised with resistant organisms
76
empirical treatment of female lower UTI in GP setting
trimethoprim or nitrofurantoin orally for 3 days
77
empirical treatment of uncatheterised male with UTI
* get cultures
* trimethoprim or nitrofunratoin orally for 7 days
78
empirical treatment of complicated UTI/pyelonephritis in the GP setting
co-amoxiclav or co-trimethoprim for 14 days
79
empirical treatment of complicated UTI/pyelonephritis in the hospital setting
* amoxcillin and gentamicin for 7 days
* co-trixomazole if penicillin allergic
80
which 2 important organisms is the ABx coverage of amoxicillin and gentamicin covering
* Coverage of Gram positives (E facealis is the most important) and coliforms (E.coli) respectively
81
chronic pyelonephritis
recurrent episodes of acute causes scarring of the kidney
82
presentation of chronic chronic pyelonephritis
* often there is no previous history of UTI and present with vague symptoms
* can present wth hypertension and uraemia
83
what is seen on renal imaging with chronic pyelonephritis
coarse cortical scarring, distortion of calyces
84
management of chronic pyelonephritis
* tight control of blood pressure
* intermittent ABx
85
ureteritis/cystitis cystica
* chronic reactive inflammatory reaction that occurs in the setting of chronic irritation of the bladder mucosa
* multiple small fluid cysts project out into the lumen, canr esmeble tumours
86
causes of cystitis cystica
chronic irritation to urothelium
* chronic bladder outlet obstruction
* chronic infection
* bladder calculi
87
pathology of cystitis cystica
* Chronic irritation results in metaplasia of the urothelium, which proliferates into buds
* These develop into cystic deposits
88
clinical features of cystitis cystica
frequency, dysuria, urgency, haematuria, suprapubic pain
89
how is TB Pyelonephritis usually acquired
can spread haematogenously, usually from the lung
90
clinical features of TB Pyelonephritis
* None are specific, so have a high index of suspicion in those with **sterile pyuria** and risk factors (e.g. HIV/AIDS)
* Weight loss, fever, loin pain, dysuria
91
what must be asked in the history of someone with suspected genitourinary TB
Ask about past lung TB, although often there is no history
92
pathology of TB pyelonephritis
* formation of caseous foci (casating granulomatous inflammation), these grow slowly with progressive renal destruction
* classically a cold abscess
93
what is a cold abscess
lacks intense inflammation associated with infection, commonly seen in TB
94
investigation of TB pyelonephritis
acid fast bacilli may be seen on ZN staining - absence doesnt exclude TB however
95
what is schistosomiasis caused by
Schistosoma haematobium
96
what is Schistosoma haematobium
a trematode (fluke) caught from fresh water exposure in tropical countries eg sub saharan africa
97
acute and chronic signs of schistosomiasis
* acute - swimmers itch
* chronic - hepatomegaly, liver fibrosis, portal hypertension
98
Schistosomiasis in renal disease
* in established disease, there are adult worms which lay eggs
* these migrate to the veins around the bladder and ureters
* initially cause haematuria
* later cause fibrosis - obstruction, hydronephrosis and kidney failure
99
what does Schistosomiasis predispose one to
urothelial malignancy (Squamous carcinoma)
