UTI's Flashcards
What is a Urinary tract infection?
Inflammatory response of urothelium to bacterial invasion
refer to an infection of any part of the urinary system from kidney to the urethra.
How is a UTI diagnosis defined?
presence of characteristic symptoms (e.g. dysuria, frequency) and significant bacteriuria . Significant bacteriuria is defined as > 105 colony forming units (CFU)/ml.
Define the following terms - Upper UTI Lower UTI Uncomplicated UTI Complicated UTI
Upper UTI: infection of the kidney (pyelonephritis) - Renal pelvis, Ureter
Lower UTI: infection of the bladder (cystitis) and urethra (urethritis)
Uncomplicated UTI: if occurring in healthy non-pregnant adult women
Complicated UTI: the presence of factors that increase the risk of treatment failure (e.g diabetes, structural abnormalities, catheter and other devices and all UTIs in men)
Which organism causes 75-90% of UTI’s?
Escherichia coli
List 4 other common microorganisms associated with uncomplicated UTIs?
List 4 assocaited with complicated UTI’s
Uncomplicated
Proteus mirabilis
Klebsiella pneumoniae
Staphylococcus saprophyticus
Streptococcus faecalis
Complicated
Streptococcus faecalis
Staphylococcs aureus
Staphylococcus epidermidis
Pseudomonas
What are extended-spectrum beta-lactamase (ESBL) producing E. coli?
organisms which are highly resistant to most beta-lactam antibiotics,
which includes penicillins and cephalosporins.
What is the Urothelium lining composed of?
- Transitional epithelium in the upper tract and bladder
- Pseudostratified columnar in membranous and spongy urethra
Describe the 3 main routes of UTI infection
Ascending: retrograde ascent of bacteria up urethra
- Bacteria from large bowel colonise perineum and ascend to bladder
- May ascend from bladder to kidney via ureter
Haematogenous: (the blood)
- Uncommon cause of infection
Lymphatic
- inflammatory bowel disease
- retroperitoneal abscess
What is the meaning of the term Pyuria and Bacteriuria
Bacteriuria: presence of bacteria in urine
Pyuria: presence of white bloods cells in urine
What does Bacteriuria with no Pyuria suggest?
Urine is colonized rather than active infection.
Pyuria Implies an inflammatory response of urothelium to bacterial infection
What are the potential causes of Pyuria with no Bacteriuria?
Carcinoma in situ
TB infection
Bladder stone
What is the meaning of the terms isolated, recurrent and unresolved UTI?
Isolated UTI:
◦ at least 6 months between infections
Recurrent UTI:
◦ >2 infections in 6 months or 3 within 12 months
◦ Re-infection: infection by different organism
◦ Persistence: infection by same organism from a focus in urinary tract
(calculi, chronically infected prostate)
Unresolved UTI:
◦ inadequate therapy
◦ May be due to bacterial resistance
Which symptoms are associated with cystitis? How is this condition diagnosed?
frequent small volume voids
urgency
suprapubic discomfort
dysuria
Investigation to confirm diagnosis:
◦ Dipstick mid stream urine:
Presence of leucocytes (indirect testing for pyuria)
75-95% sensitive for UTI
Presence of nitrite (indirect testing for bacteriuria)
Specificity >90%
Sensitivity 35-85%
◦ Urine microscopy
How is Cystitis treated?
Uncomplicated:
Short course antibiotics e.g. Trimethoprim
Nitrofurantoin is also first line for alot of places
◦ Complicated :
7-10 day course e.g. Augmentin and investigate further
Which further investigations may you need to conduct for cystitis?
Abdominal X-ray (Kidney / Ureters / Bladder [KUB])
◦ Renal ultrasound
◦ Possibly intravenous urogram / CT urogram if structural abnormality
What are the symptoms for pyelonephritis and which investigations are conducted for this condition?
Symptoms and signs:
◦Flank / loin pain
◦ Nausea and vomiting
◦ Fever and chills
◦ Lower urinary tract symptoms (LUTS)
Investigations
◦ MSU – dipstick and send for culture
◦ Bloods – FBC, U&E, blood cultures
◦ AXR, Renal USS, CT urogram
How is pyelonephritis treated?
Not systemically unwell consider outpatient management – 10 days oral
antibiotics - oral fluoroquinolone such as ciprofloxacin
◦ systemically unwell – admit for IV co-amoxiclav antibiotics, and consider IV antibiotics at
home -
ceftriaxone may be used for patients with urosepsis or acute severe pyelonephritis.
List 4 organism which mainly cause pyelonephritis
E. Coli
◦ Less commonly Enterococci/Klebsiella/Proteus/Pseudomoas
State the main complication for Pyelonephritis and describe how it is treated
Perinephric abscess (abscess in Gerota’s fascia (perinephric space) ):
infection extends outside parenchyma
Treatment:
drainage of collection (radiologically or formal open incision)
antibiotics until resolution of infection (clinically and radiological evidence)
What are the risk factors for Pyelonephritis complications and which organisms can be responsible for these complication?
Diabetes Obstructing calculus (stone)
Microbiology:
S. aureus
E. coli
Proteus
UTI’s can cause urosepsis - describe the sepsis 6 principal
3 IN
- high flow oxygen (94-98%)
Those at risk of carbon dioxide retention (COPD) should have a target of 88-92%
- IV fluids should be started (crystalloid )
- Antibiotics - piperacillin/tazobactam (tazocin)
3 OUT
- two sets of blood cultures should be taken (before giving antibiotics)
- serum lactate should be obtained from blood gas
- Urine output should be measured ideally with a catheter
Which factor increase your risk of an UTI via the Ascending route?
Increased risk: vesicoureteric reflux/impaired ureteric peristalsis e.g. in patients with stones
List 3 modifiable risk factors for UTI’s?
Contraceptive diaphragm
Recurrent sexual intetocurse
indwelling catheter
What effect does Trimethoprim have in renal function tests?
Causes a rise in creatinine
