UTIs Flashcards by Elizabeth Stevens

What host factors are there which allow for infection?

Shorter urethra in females
Obstruction due to stones, enlarged prostate, pregnancy or tumours
Neurological - incomplete emptying
Ureteric reflex

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What are the normal UTI tract defence mechanisms?

Regular flushing during voiding to remove organisms from distal urethra
Antibacterial secretions into urine and urethra
Urine osmolality (high)
High urine pH

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Why does incomplete emptying increase chance of infection?

Residual urine is left in the b,added and some can be forced back up the ureters

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What bacterial factors allow for infection?

Ability to adhere to epithelial cells - determines degree of virulence

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How do E. coli get into and adhere to the urinary tract?

Have flagellae for motility
Aerobactin for iron acquisition in an iron-poor environment
Haemolysin - pore forming
Adhesins on fimbrae and on cell surface

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What are the more cellular urinary tract defence mechanisms?

Neutrophils which are activated by adhesions. Found on mucosal surfaces
Complement activation with IgA production by urothelium
Commensal organisms
Urothelium has proteins in the mucus which interfere with bacterial binding

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What predisposes people to a UTI?

Trauma - due to catheterisation, sex because it affects the urothelium

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Define dysuria

Painful/difficult urination

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Define pyuria

Pus in urine

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What is pyelonephritis?

Infection of the kidneys

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What are the symptoms of pyelonephritis?

Fever
Loin pain
Tenderness
Significant bacteriuria

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What can be seen with imaging in pyelonephritis?

CT scan shows wedge shaped areas of inflammation
Small renal cortical abscesses and streaks of pus in the renal medulla
Focal infiltration of polymorphonuclear leukocytes and polymorphs in tubular lamina

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Complications of acute pyelonephritis if left untreated?

Significant permanent kidney damage (rare)

Inflammation in renal cortex

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How does reflux nephropathy occur?

Combination of vesicoureteric reflux and infection acquired in infancy and early childhood
Vesicoureteric valve normally prevents reflux of urine when bladder empties but in some children, the mechanism can be void
Secondary consequence is incomplete emptying as urine returns to bladder - predisposes to infection and kidney damage

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How is reflux nephropathy diagnosed?

CT scan showing irregular renal outlines and a reduction in renal size
Can be unilateral or bilateral
Affect all or part of the kidney

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When does urine reflux normally stop?

Around puberty

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What can occur if damage persists from reflux nephropathy?

Progressive renal fibrosis
Further loss of function in severe cases
Predisposed to hypertension in later life

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Who does reflux nephropathy normally affect?

Children

Suspect it if they ‘fail to thrive’

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What is chronic interstitial nephritis?

Renal impairment following chronic inflammation

Can be caused by infection or an adverse reaction to drugs

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What is bacterial cystitis?

Inflammation of the bladder caused by bacteria

Common in women as a result of sexual intercourse

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Symptoms of bacterial cystitis?

Frequency and dysuria
Smelly urine
Pyuria
Haematuria

What is prostatitis?

Inflammation of the prostate gland

Symptoms of prostatitis?

Fever
Dysuria
Frequency
Perineal and lower back pain

Symptoms of an upper UTI?

Loin pain
Fever
Oliguria
Systemic symptoms

Symptoms of a lower UTI?

Frequency and dysuria Smelly urine Polyuria Haematuria

Define oliguria

Production of abnormally small amounts of urine

What are possible complications of UTIs?

Long term renal damage | Common source of life threatening Gram negative bacteraemia

What is covert bacteriuria?

Asymptomatic bacteria in the urine

When is covert bacteriuria important to detect and how is it detected?

Children and pregnancy | Culture

Common organisms responsible for UTIs?

Gram negative rods Particularly coliforms - E. coli In young women and hospitalised patients can also be caused by coagulase negative staphylococci

Risk factors for a UTI?

``` Female Sexual intercourse Spermicide in females Pregnancy Menopause Immunosuppression Urinary tract obstruction Catheterisation Constipation ```

What is an uncomplicated UTI?

A UTI where the anatomy of the urinary react is normal and renal imaging will be normal. There is no underlying condition contributing to the infection Unlikely to result in serious kidney damage

Who would have an uncomplicated UTI?

Women of child-bearing age and healthy

What is a complicated UTI?

Infection of the lower urinary tract with an associated condition such as structural or functional abnormalities of the urinary tract or the presence of an underlying disease, which increases the risk of acquiring an infection or failing therapy

What can complicated UTIs lead to?

Severe and rapid kidney damage | Risk of Gram negative septicaemia

How to diagnose a UTI?

Midstream specimen of urine Dipstick - Gram negative bacteria will reduce nitrates to nitrites however many false positives -> low sensitivity Leuokocyte esterase may be present -> pyuria Test for haematuria and proteinuria

When is dipstick testing not useful to diagnose UTIs?

Acute uncomplicated UTI Men with typical/severe symptoms Catheterised patients Older patients with asymptomatic bacteriuria

How do you collect a sample in small children?

Adhesive bag | Unreliable

Now do you collect a sample from a catheterised patient?

Needle up a special tube in the catheter

What is a suprapubic aspiration?

Put a needle through the abdominal wall to take a urine sample

How is a urine sample transported?

4*C | Boric acid

When is microscopy done with UTIs?

``` Suspected kidney disease Suspected endocarditis Children under 6 Schistosomiasis Suprapubic aspirates ```

What is sterile pyuria?

When a UTI is present but unable to be cultured

Why might you get sterile pyuria?

Patient has already been treated with antibiotics Infected with difficult bacteria to isolate or culture eg chlamydia, TB Appendicitis

What is urethral syndrome?

When women present with symptoms of a UTI but not due to a bacetrial cause

What can cause urethral syndrome?

Vaginal infection STI Mechanical, physical or chemical causes

Treatment of uncomplicated UTIs? (Cystitis)

3 day course of trimethoprim

Treatment of complicated UTI?

Trimethoprim, nitrofurantoin or cephalexin for 7 days

Treatment of pyelonephritis and septicaemia?

14 day course of co-amoxiclav or ciprofloxacin | IV

How does ciprofloxacin work?

It is a quinolone | Inhibits bacterial DNA gyrase, preventing bacterial supercoiling

How do you treat prostatitis?

Ciprofloxacin

When would you give a patient prophylaxis for UTIs and what would you give?

If they have had 3 or more episode in one year and there is no treatable underlying condition Trimethoprim/nitrofurantoin - 1 at night