lecture 39: Dysuria: Urinary Tract Infection Flashcards
Dysuria is the cardinal symptom for a urinary tract infection/ What is it?
Pain whilst passing urine, often a burning/stinging sensation.
- Something in the urine that irritates pain fibres and/or
- sensitive mucosa so the pain fibres get stimulated
What other questions do we want to ask?
- Seek evidence that there is bladder dysfunction
- Frequency
- Hesitiancy (need to go but not much comes out)
- Inflammed, boggy, not doing its job
- cramping pain (strangury): suprapubic
- If these are there, very likely cystitis.
- If there is not urgency, it’s likely urethritis
- Contraception?
How do you diagnose cystitis?
-
Mid-stream urine collection ($35): Microscopy, culture, susceptability.
- Urine will become contaminated by colonising bacteria as you pee, so the first part flushes this away, and we collect a more sterile collection more representitive of the bladder
- if they grow anything in a resonable amount they’ll do a susceptable testi (only if it grows at a reasonable amount as it could just be due to contamination)
-
Urine dipstick: WBC/leucocyte esterase. Cheap plastic with chromatograph that measure pH, sugar content8 and leukocyte esterase
- A high amount of leukocyte esterase correllates with a high number of neutrophils in the urine**** so there will be inflammation of the bladder
- IS THERE PYURIA (WBC in urine)
what to do
Answer: A
How common is cystitis
Women > Men
- *Sexually active young women** 2-4%
- *Post menopause:** increases due to the drop of oestrogen, (which usually supports healthy flora), different bacteria can now take place.
Institutionalised (no longer independent): Mostly due to bladder dysfunction 20-50%
What factors can increase the risk of a UTI in both Males and Females?
What is the common sense, cost saving approach to diagnosing and treating UTI?
- Typical SYmptoms? y/n
- Dipstick shows pyuria? y/n
- 96% of people with symptomatic UTI have >10mill WBC/litre
- dipstick sensitivity is >8million WBC/litre so will usually always show
- pyuria in the absence of symptoms does NOT indicate cystitis
- Treat further problems? y/n
- Reassess and send MSU to lab
- microscopic visualisation of bacteria correlates with culture contamination is important issue (w > m)
What are the bacteria that cause Cystitis?
- E coli: 80% of the time!
- also causes most of pylonephritis!
- Staphylococcus saprophyticus: common in young women
- Good at colonising urethra but cannot get to kidneys! can catalase peroxide,
- Therefore never seen in hospital!
Why is E.coli the main causer of cystitis?
- Sequesters Iron (Fe): ones that can’t fo this aren’t as virulent.
- Fimbriae: Mediate attachment to urothelium. Can change from type II (bladder) to type I (renal)
-
Polysaccharide Capsule: resist phago cytosis and opsonisation, also protect bacteria against changing pH and osmolality
- N. gonorreiae: never causes disease as it cannot live in urine
- Alpha haemolysin released that damages epithelial cells
Trimethoprim?
Commonly used anti-folate drug used to treat cystitis!
- Folate is required from bacteria to produce nucleotides (purines)
- Broad spectrum antibiotic!
- INTERFERE with bacterial division: “bacteriostatic”
- Stops dihydroteroic acid → dihydrofolic acid
also sulphonomides discovered earlier and used
How could E. coli bacteria overcome the inhibiting effects of trimethprim
- By making excess enzyme (dihydrofolate synthetase) and saturating the trimethoprim, overwhelming its effects
- Dump this pathway altogether and get the needed folate elsewhere that is around using transporters
- Pump trimethoprim out of themselves via cell membrane pumps!
These all lead to antibiotic resistance
What are the main causitive feature in elderly peopl?
Females:
- post menopause
- Urinary tract abnormalities
- urethrocele, rectocele, bladder diverticula
- Neurological disease
- incomplete bladder emptying (usually we fill to ~400ml and then completely empty)
Males:
- strictures
- stones
- prostatic disease
- Neurological disease
Don’t give anti-folates to….
- pregnant women (obviously)
- high doses for long periods can suppress bone marrow function
-
allergy: rash, can be very severe (***see pic Steven Johnson syndrome)
- SJ syndrome: allergy of both skin and mucosa surfaces, (mouth, face, genitourinary systems). Can be equal to burns, end up in critical care. A second attack will be worse!!!
- mostly the sulfur drugs causing issues
Good options to treat cystitis. WHich one do you use?
- trimethprim (71%)
- nitrofuratoin (98%)
You would use the nitrofuratoin as more effective BUT as it’s needed to be taken 4x a day is a nuisance and decreases compliance.
Use trimethprim at bedtime so you aren’t going to pee the drug out and it can linger in the bladder.
What happens once the urothelium is damaged?
It releases cytokines, these causes symptoms and recruit neutrophils
Neutrophils come to bladder wall and in the urine, and this is when the dysuria, burning pain comes to play once the bladder become boggy and odematous
What is this?
Pylonephritis!
- FEVER with UTI is a way to distinguish
- Bacteraemia (15-30%)
- mortality (10%)
- many patients are admitted and treated in hosptials
- investigate: blood cultures and urine cultures, blood tests to look for organ impairment (eg; renal function)
- Radiological studies (US scan): NOT required to make diagnosis, but if used if suspected abnormaluty of UT (eg; stones) but if people deteriorate despite treatment
