Renal and Urinary System Flashcards
By what age are most children dry by day and dry by night?
Dry by day at 2 years
Dry by night at 3 years
What are the two types of enuresis (involuntary urination)? More common in M or F?
Nocturnal - twice as common in males
Daytime (much rarer) - more common in females
What is primary enuresis?
Continence never established
What is secondary enuresis?
Loss of continence after a continuous period of at least 6 months dryness (most likely to have organic cause)
What are some biological causes of nocturnal enuresis?
1) UTI = 5% secondary enuresis
2) Urinary tract abnormalities
- Low bladder capacity
- Incomplete bladder voiding
- Detrusor instability secondary to constipation
3) Lack of ADH during sleep
4) Genetic predisposition
- 70% have FH
5) Diabetes causing polyuria
What are some psychosocial causes of nocturnal enuresis?
1) Inability to wake to full bladder sensation
2) Psychosocial trauma eg distress, bullying, abuse
3) Accidental behavioural conditioning eg child comes to parents bed when wet
4) Developmental delay
What is a major cause of daytime enuresis?
Bacteriuria
Cycle - bacteriuria causes detrusor instability causes urge incontinence causes damp pants and perineal irritation causes bacteriuria
What investigations can be done for enuresis? (4)
1) DM testing - random and fasting blood glucose
2) Urinalysis if symptomatic
- Bacteriuria is common in girls with daytime enuresis
3) Early morning urine sample - assess urine osmolarity to test ability of kidneys to concentrate urine
4) USS to look for GU tract abnormality
5) Consider psychological screening
What is the management of enuresis?
At what age would you start intervening in enuresis?
Intervene from 7 years old
Reassurance and counselling for parents - explain it is beyond child’s conscious control and parents should stop punitive procedures as these are counterproductive
Avoid caffeine and fruit juice
Star charts
Enuresis alarm
Medication
What medications can be given for enuresis?
Desmopressin
- Antidiuretic can be taken as tablets, sublingual or nasal spray at bed time
- Reduces urine output - provides short-term relief from bedwetting for holidays/sleepovers
- Avoid excessive fluid intake for 8hrs after dose
Anticholinergics = if daytime symptoms / unresponsive to desmopressin
Why is a UTI significant in young children?
It may be a marker for urinary tract abnormalities
Half of child UTI pt have renal tract abnormality
When clinically should an upper UTI be assumed?
Fever of 38 or higher + bacteriuria
Fever lower than 38 but with loin pain/tenderness + bacteriuria
When are UTIs considered recurrent?
1) 2 x upper UTI
2) 3 x lower UTI
3) 1 x upper + 2 x lower UTI
What features make a UTI atypical?
1) Seriously ill / septicaemia
2) Poor urine flow - sign of obstruction
3) Presence of abdo / bladder mass
4) Lack of response within 48hrs to treatment with suitable abxs
5) Not caused by E Coli
6) Raised creatinine
Are UTIs more common in boys or girls?
More common in boys up to 6 months
More common in girls after
What are some risk factors for UTI?
- Age < 1 year
- Urinary tract abnormality
- Voiding dysfunction
- Vesicoureteral reflux
- Spinal abnormalities
- Constipation
- Immunosuppression
- Sexual abuse - more likely to cause urinary symptoms than infection
How may a UTI present in infants <3 months?
Presents differently than in older children
Fever Vomiting Lethargy Irritability \+/- poor feeding \+/- FTT
Less commonly: Abdo pain Jaundice Haematuria Offensive urine
More likely to develop urosepsis
Less likely to be due to E coli
What is the most common presentation of a UTI in a preverbal child?
Fever with no apparent cause
How may a UTI present in a child >3yrs?
Urinary symptoms eg freq, dysuria, suprapubic / abdo / lumbar pain
Dysfunctional voiding
Fever, malaise, vomiting, haematuria, offensive / cloudy urine
Ddx for UTI (6)
Vulvovaginitis Urethritis Irritation e.g. soaps Threadworm infestation Balanitis Sexual abuse
What should be included on examination of a child with a UTI?
Temperature
Cervical lymph nodes
Abdomen - constipation, masses, tender / palpable kidney
Back - signs of spina bifida
Genitalia - phimosis, labial adhesions, vulvitis, epididymo-orchitis
How may urine be collected in a child with a UTI?
Clean catch - most ideal
Collection bag attached to clean genitalia - avoid due to contamination
Urine collection pads - avoid due to contamination
Supra-pubic aspirate - gold-standard but only consider if child is very unwell
What may urinalysis show in a UTI?
Nitrites +
Leucocytes +
Haematuria +
Albumin +
Why are nitrites not very sensitive dipstick test in infants?
Not all urinary pathogens reduce nitrate to nitrite
Urine not often held in bladder long enough for conversion to occur
What imaging scans should be done in infants/children with atypical/recurrent UTIs?
< 6 months
6 months-3 years
> 3 years
< 6 months
- USS
- Micturating cystography (MCUG)
- DMSA scintigraphy
6 months-3 years
- USS
- DMSA scan
> 3 years
- USS
What are USS effective and ineffective at visualising when investigating a UTI?
Accurately assess renal size and outline and identify most congenital abnormalities, renal calculi and hydronephrosis or hydroureter (indicating the presence of obstruction or severe reflux)
Less effective in detecting mild or moderate vesico-ureteric reflux
How is micturating cystography (MCUG) carried out? What is it looking for?
Catheterise bladder, fill with radio-opaque dye, watch on X-ray whilst child micturates
Will see urethral abnormalities or vesico-ureteric reflux
What is the gold standard investigation for VUR?
Micturating cystography
Only imaging technique that provides information about the urethra
What DMSA scintigraphy effective at imaging? How does it work?
Gold standard for renal parenchymal defects
- Inject IV radiolabelled isotope and visualise on scintigraphy
- The working renal tissue picks up the isotope so a renal image is seen, then the scars are shown as blank areas
- Rate of excretion is seen as the kidney clears the isotope
When are DMSA used?
4-6 months post infection - show scarring
Which children presenting with a UTI should be immediately referred to specialist care?
Serious illness
3 months or younger
Do not delay treatment if sample cannot be obtained and the child is at serious risk of illness
What is the pharmacological management of a child with a UTI? Lower and upper
< 3 months - refer immediately to hospital for IV abx (cefotaxime)
> 3 months with upper UTI
- Usually PO co-amoxiclav for 7-10 days
or
- IV cefotaxime for 2-4 days followed by PO abx for 7-10 days
If lower UTI, trimethoprim PO for 3 days
What is dysfunctional voiding syndrome?
Abnormality of emptying, due to either a small-capacity, unstable bladder or a large-capacity, poorly emptying bladder
What are potential complications of a UTI in children? (3)
1) Renal scarring - more likely in children with vesico-ureteric reflux
2) Hypertension - associated with renal scarring
What is the diagnosis of infants or children that have:
1) Bacteriuria and a fever of 38 or more
2) Fever <38 associated with loin pain/tenderness and bacteriuria
3) Bacteriuria but no systemic symptoms or signs?
1) Pyelonephritis/upper UTI
2) Pyelonephritis/upper UTI
3) Cystitis/lower UTI
What measures can be adopted to prevent UTI?
Good fluid intake to increase urine output
Practice regular voiding and ensuring bladder completely emptying
Prevention of constipation
Good perineal hygiene
For girls:
- Wipe from front to back
- Avoid perineal irritation from bubble baths or soaps
- Thorough drying of perineum
- Wear loose fitting clothes