9 Flashcards
What are the clinical syndromes of lower UTI?
- bacterial cystitis
- Abacterial cystitis
- prostatitis
What is bacterial cystitis?
- frequency and dysuria often with pyuria and haematuria
- cloudy urine
- nocturia or frequency
- urgency
- suprapubic tenderness
- mild Pyrexia
What is abacterial cystits?
-same as bacterial cystitis but without significant bacteriuria
What is prostatits?
-fever, dysuria, frequency with perineal and low back pain
What are common clinical syndromes of upper UTI?
- acute pyelonephritis
- chronic interstitial nephritis
What is acute pyelonephritis?
-symptoms of cystitis plus fever and loin pain
-tenderness
-rigours
Nausea/vomiting
See session 9 UTI slde 12
What is chronic interstitial nephritis?
- renal impairment following chronic inflammation
- infection is one of many causes
What is a clinical syndrome of asymptomatic UTI?
-covert bacteriuria
What is covert bacteriuria?
-detected only by culture important in children and pregnancy
What is a common source of Gram-negative septicaemia?
UTI
What major defences does the urinary tract have in order to protect it from UTI?
- regular flushing during voiding which removes organisms
- antibacterial secretions into urine and urethra
- vesico-urethral valves
- immunological factors
- mucosal barriers
- urine acidity (prevents bacteria from multiplying)
- one way flow
What host factors promote UTI?
- shorter urethra: more infections in females
- obstruction: enlarged prostate, pregnancy, stones, tumours
- neurological: incomplete emptying, residual urine
- ureteric reflux: ascending infection from bladder especially in children
- ascending colonization from bacteria from perineum
What bacterial factors promote UTI?
- faecal flora: potential urinary pathogens colonies periurethral area
- adhesion: fimbriae and adhesions allow attachment to urethral and bladder epithelium
- K antigens: allow some E.coli to resist host defences by producing polysaccharide capsule
- Haemolysins: damage membranes and cause renal damage
- Urease: produced by some bacteria (ex. Proteus)
- Cystitis: colonization in bladder
- Pyelonephritis: colonization in kidney
See session 9 UTI slide 6-7, 9
What are some risk factors that will cause UTI?
- obstructive causes: stones, enlarged prostate, retroperitoneal fibrosis
- neurological conditions affecting bladder emptying: multiple sclerosis, stroke
- pregnancy: enlarged uterus, hormonal effects on relaxation of musculature, can’t contract bladder as effectively
- abnormal renal tract: vesico-ureteric reflux in children, indwelling urinary catheter
- impaired host defence: diabetes mellitus, immunosuppressive
- patients with kidney disease
- patients on dialysis or with kidney transplants
Describe the virulence factors of E.coli
- flagellar: movement
- pili: attachment
- capsular polysaccharide: colonization
- haemolysin, toxins: damages host membranes and causes renal damage
See session 9 UTI slide 10
What other causes of urethral inflammation (urethritis) will lead to dysuria?
- STI
- post sexual intercourse
- contact with irritants
- symptoms of menopause, strophic vaginitis or vaginal atrophy
What is uncomplicated UTI?
- infection by a USUAL organism in a patient with a NORMAL URINARY TRACT AND NORMAL URINARY FUNCTION
- may occur in males and females of any age
What is a complicated UTI?
- 1 or more factors that predispose to persistent infection, recurrent infection or treatment failure
- abnormal urinary tract
- virulent organism (i.e. staph aureus)
- impaired host defence (immunosuppression, poorly controlled diabetes mellitus)
- impaired renal function
What is the difference between complicated and uncomplicated UTI?
- infections in kids and men and some cases of pyelonephritis may meet the definition of uNCOMPLICATE
- BUT in practice most cases in children, men and pregnant women, are investigated and managed as “complicated”
See session 9 UTI slide 15
In what instances would you use a urine culture to investigate for UTI?
-in complicated UTI (i.e. pregnancy, treatment failure, recurrent infections, suspected pyelonephritis, complications, male, children)
How would you collect the specimen for urine culture?
- Mid-stream urine (MSU): cleansing not required, ideally holding labia apart in women so it doesn’t infect urine
- clean catch in children (get kids to pee in pot)
- collection bag (20% false positives due to contamination of perineum)
- catheter sample
- supra-pubic aspiration (gold standard, poke needle into bladder through the skin)
- culture urine within 4 hours of collection, refrigerate or use boric acid preservative
What is a urine dipstick and when would you use it?
- Urine dipstick: leukocyte esterase, nitrites (since Coliforms break down nitrics to nitrites), blood, pH, protein
- useful in females <65years with suspected uncomplicated UTI as an aid to diagnosis
- useful in ruling out infection in children >3 months old
- not useful in: patients >65 year old (asymptomatic infection common) and catheterised patients
See session 9 UTI slide 18-20, 22-23
How would you visually inspect a UTI?
In boric acid bottle
- if clear no UTI
- if cloudy then probably a UTI, due to numerous WBCs
See session 9 UTI slide 21
How would you analyze the urine cultures?
- screen it with microscopy
- detects white cells, red cells, epithelial cells and bacteria
See session 9 UTI slides 24-28
Who would get imaging of urinary tract done for UTI?
- considered in all children with UTI
- valuable in septic patients to identify renal involvement (i.e. pyelonephritis)
- Males: posterior urethral valves
- Females and kids: vesicles-ureteric reflux
What is sterile pyuria?
-WBC in urine but no UTI Can be caused by: -prior antibiotics -urethritis (chlamydia/gonococci) -vaginal infection/inflammation -TB (need prolonged incubation) -appendicitis -fastidious organisms (organisms that are very slow-growing but they are rare)
What is asymptomatic bacteriuria?
- significant levels of bacteria in urine with no UTI symptoms
- high prevalence in elderly, indwelling catheters
- screened for and treated only in pregnancy (untreated leads to higher risk of premature labour and pyelonephritis)
- that’s why no urine dip sticks for old people since they have asymptomatic bacteria
How can we treat UTI?
- increase fluid intake
- regular analgesia (i.e. paracetamol/ibuprofen)
- no good evidence that cranberry products work
- address underlying disorders
- 3 day courses for uncomplicated UTI
- 5-7 day course for complicated lower UTI (i.e. pregnant, male, underlying disorders)
- CSU: only treat if systemically unwell
How do you treat simple cystitis?
- uncomplicated infections can be treated with nitrofurantonin, trimethoprim, pivmecillinam or fosfomycin
- 3 days course as effective as 5 or 7 days
- limiting prescription to 3 days reduces the selection pressure for resistance
See session 9 UTI slide 34
How do you treat complicated lower UTI?
- ex. Male, pregnant women, catheter associated UTI
- nitrofurantonin, trimethoprim, pivmecillinam, fosfomycin or cefelexin (for pregnant women) may be used (review susceptibility report)
- 5 to 7 day course
How would you treat pyelonephritis (upper UTI)/septicaemia?
- Pyelonephritis 7-10 days course
- use agent with systemic activity (NOT nitrofurantonin, fosfomycin)
- possibly IV initially unless good PO absorption and patient well enough/tolerating orally: Co-amoxiclave, ciprofloxacin (effective as a 7 day course), gentamicin NB IV only; nephrotoxic
Who would you give prophylaxis to in regards to a UTI?
- these are long term low-does antibiotics
- give them to pt’s who have had >3 episodes in one year
- despite behavioural and personal hygiene measures
- no treatable underlying condition
- choice of antibiotics according to recent culture and susceptibility results (i.e. trimethoprim or nitrofurantonin as a single nightly dose)
- ensure all breakthrough infections documented
What is a urinary tract caliculi?
- stone formed from calcium
- made up of calcium oxalate and calcium phosphate
- calcium is 80% of the stones
- uric acid makes up about 9%
- struvite (magnesium ammonium phosphate hexahydrate, from infection by bacteria that have urease) makes up 10%
- 1% makes up the rest: cystine, drug stones, ammonium acid irate
How often do urinated tract caliculi occur?
- incidence of acute renal colic is 1-2cases/1000/year
- important cause of morbidity
- high recurrence rate 60-80%
- most small stones pass spontaneously within 1–2 months
- stones>6mm likely to require intervention
What is the aetiology of urinary tract caliculi?
- metabolic: secondary hypercalcuria (causes salt to crystallize in the urine)
- urinary infection: proteus, pseudomonas, klebsiella
- diet: high in table salt, obesity, ketogenic diet
- medication: furosemide, diuretics
- genetic: primary hyperoxaluria, cystinuria (mainly in kids)
How do you diagnose urinary tract caliculi?
- hydronephrosis (dilation of kidney if it’s blocked)
- loin to groin pain, haematuria
- CT KUB diagnostic accuracy >95%
- identify stone size and position associated obstruction/complication
- identify alternative diagnosis (ex. Ruptured AAA, appendicitis)
See session 9-stones slide 4
How would a large renal calculus appear on a US?
-US wave cannot penetrated beyond the stone so there is a shadow below it
See session 9-stones slide 5
What is the likelihood of passage of ureteric stones?
- kidney stones <5mm in diameter have a chance of being passed
- 5-7mm have 50% chance
- > 7mm needs urological intervention
See session 9-stones slide 7
How are kidney stones categorized?
Staghorn: filling numerous major or minor calices
Non-staghorn: calyceal or pelvic in location
Ureteral: proximal, middle or distal
How do we treat urinary caliculi stones?
- depends on stone size, location and composition
- extracorporeal shock-wave lithotripsy- ESWL
- Percutaneous nephrolithotomy- PCNL (more invasive, make a hole through skin into kidneys to remove stone), see session 9-stones slide 11-14
- Ureteroscopy: camera into ureter, apply laser treatment to remove stone, invasive
- open surgery/nephrectomy
- urinary tract sepsis related to stones is highly morbid
How does ESWL work and what are the indications?
- non invasive treatment to fragment urinary calculi
- utilizes shock waves from a lithotripter
- stone localized with fluoroscopy or US (gets shattered by shockwaves)
- fragments pass out over several weeks
Indications
- suitable: <2cm can be localized with imaging
- unsuitable: large renal calculus >2cm, in lower pole calyx, radiolucent, resistant to ESWL, body habitus, weight
See session 9-stones slide 9-10
What is paediatric cystinuria?
- children it is different
- recurrent infections, failure to thrive
- cystinuria is a hereditary condition
What is DMSA split function?
-looking at function of each kidney separately
See session 9-stones slide 16-19
