Urinary: UTIs Flashcards
What is the prevalence of UTIs by age?
Spike in infancy: early presentation often indicates abnormality of the urinary tract
Spike in late teens - 30’s: called honeymoon cystitis and related to sexual activity
Increase in old age: cause in men is mostly obstruction via an enlarged prostate
What are the defence mechanisms of the urinary tract against UTIs and how can they go wrong?
Long urethra (more UTIs in females) The ability to pass urine to clear bacteria - goes wrong when there is: - obstruction eg prostate, pregnancy, stones - neurological problems which mean there is incomplete emptying and residual urine
The ureteric reflex which prevents back flow of urine back up the ureters - this can be faulty, presents especially in children
What are some bacterial factors that make them more likely to colonise host:
- Haemolysins which damage host membranes
- Fimbriae allow attachment to host epithelium
- Urease which breaks down urea and creates a favourable environment for growth
- Polysaccharide capsule which resists host defence
What are the most common bacteria that cause UTIs?
Coliforms such as E. Coli
They are aerobic gram negative rods which are part of the normal bowel flora
What is cystitis and what are the symptoms?
A lower UTI
Symptoms are frequency, urgency, dysuria and sometimes a low grade fever
What is pyelonephritis?
What are the symptoms?
An upper UTI - Can be acute or chronic
Symptoms are febrile, loin pain which is usually unilateral, dysuria and frequency
What is the difference between an uncomplicated and complicated UTI?
Uncomplicated UTI: Infection by a usual organism in a pt with a normal urinary tract and normal urinary function.
(but in reality is women on child bearing age that isnt pregnant)
Complicated UTI: factors present that predispose a pt to persistent, recurrent and hard to treat infection.
(but in reality males, children, elderly and PREGNANT)
How are UTIs diagnosed?
In uncomplicated UTIs the diagnosis is made purely on presentation and near pt testing eg turbidity and dipstick testing
In complicated UTIs the urine is cultured
How do you assess the turbidity of urine?
Look at the urine, if it is cloudy then there is white cells and most likely an infection
What does dipstick testing measure?
Leukocyte esterase: a marker of leukocytes
Nitrite: break down of nitrate by bacteria
Haematuria
Proteinuria: marker of abnormality of urinary tract rather than UTI
What is urethral syndrome?
Irritation and inflammation of the urethra that presents similarly to UTIs.
It is treated the same as UTIs and the majority of pts recover
When is imaging of the urinary tract considered?
Considered in all children with a UTI.
Valuable in septic pts to identify renal involevement
Females with vesico-ureteric reflux
What are some causes of sterile pyuria? (pus in the urine but no bacteria present)
- antibiotics have suppressed bacterial growth
- urethritis
- vaginal inflammation
- TB (bacilli wont grown on the medium)
- appendicitis which pushes on the bladder
In what situations does asymptomatic bacteriuria need treatment?
Only requires action in pregnancy and urological surgery
How are UTIs treated?
Increase fluid intake to naturally flush out bacteria
Address underlying cause eg DM, enlarged prostate
Uncomplicated: 3 day course of trimethoprim or nitrofurantoin
Complicated: 5-6 day course of trimethoprim, nitrofurantoin or cephalexin
