Congenital abnormalities, UTI & nocturnal enuresis Flashcards
Renal agenesis/Potter syndrome?
1) Absence of both kidneys
2) Since amniotic fluid is mainly derived from foetal urine there is oligohydramnios (amniotic fluid volume less than gestational age) - foetal compression.
3) Characteristic face - low-set ears, beaked nose, limb deformities and lung hypoplasia
4) Infant may be stillborn or die soon after birth from respiratory failure
Multicystic Dysplastic Kidney?
1) Kidney is replaced by cysts of variable sizes with atresia of the ureter, no renal tissue and no connection with bladder
2) No urine produced - Potter syndrome is developed if lesion is bilateral
Polycystic kidney disease?
1) Some or normal renal function is maintained but both kidneys are always affected
2) Autosomal recessive PKD - large cystic kidneys with diffuse bilateral kidney enlargement
Autosomal dominant PKD - large cystic kidneys with separate cysts of varying size between renal parenchyma - HT, haematuria and renal failure in childhood
Pelvic kidney/Horseshoe kidney?
1) When the lower poles of the kidney fuse in the midline (Horseshore)
Or when the kidney is normal but located in the pelvis rather than the abdomen.
2) Abnormal position may predispose to infection or urinary obstruction.
Duplex system?
1) Two ureters from 1 kidney - 1 ureter typically has abnormal drainage and often refluxes whereas the other ay drain ectopically into the urethra/vagina and urine flow may be obstructed
Urinary tract obstruction:
- Antenatal diagnosis of urinary tract abnormalities required PROPHYLACTIC ABx.
1) Unilateral hydronephrosis: Ultrasound at 4-6 weeks - causes include pelvic ureteric obstruction or vesicoureteric obstruction.
2) Bilateral hydronephrosis: Ultrasound within 48 hours of birth to exclude posterior urethral valves
Causes: Bladder neck obstruction due to disruption of nerve supply. Posterior urethral valves - mucosal folds or membrane result in obstruction at the posterior urethra (IN BOYS ONLY)
Unilateral or bilateral hydronephrosis can, at worst, result in dysplastic kidneys - small, poorly functioning and may contain cysts. Severe and bilateral cases will have Potter syndrome (renal genesis)
What is a UTI?
- Growth of bacteria within the upper urinary tract (pyelonephritis) or lower urinary tract (cystitis) or both - usually associated with bacteriuria and pyuria (pus in urine)
- Defined as >10^5 organisms/ml from fresh mid-stream urine.
Epidemiology and aetiology of UTI?
Ex: More common in females, 0-14 years
- If these is fever and systemic involvement - may involve the kidneys
- If no fever - may be due to cystitis
- UTI in childhood is important as half patients have structural abnormality in urinary tract. The development of pyelonephritis may damage growing kidney by forming a scar - predisposing to hypertension - predisposing to chronic renal failure (if scarring is bilateral)
Aetiology: E.coli (MOST COMMON), Klebsiella (2nd), Proteus (more common in boys), Pseudomonas
Risk factors and pathophys of UTI?
1) Antenatally diagnosed urinary tract abnormality
2) Incomplete bladder emptying
3) Obstruction by a loaded rectum from constipation
4) Vesicoureteric reflux (VUR)
Pathophys: UTI can spread up the urinary tract either remaining in the bladder (cystitis) or going further up to the kidney (pyelonephritis) resulting in long term damage in some cases.
Vesicoureteric reflux (VUR)?
- Developmental anomaly of the vesicoureteric junctions
- 30-50% familial link (with first degree relatives), or can be secondary to bladder pathology, or can occur temporarily after UTI.
- Ureters are displaced laterally and enter directly into bladder rather than at an angle.
- Detected by micturating cystourethrogram (MCUG): contrast introduced into bladder via urethral catheter, detects VUR and urethral obstruction.
- Mild reflux - reflux into ureter only, severe reflux - gross dilation of ureter and renal pelvis - predisposes to infrarenal reflux and renal scarring from UTI.
- Infection as a result of VUR may result in renal scarring - shrunken, poorly functioning segment of the kidney (reflex nephropathy) and if scarring is bilateral and severe 0 chronic renal failure can develop.
Presentation of UTI? Ddx?
Infants - non specific: fever, lethargy/irritable, poor feeding/failure to thrive
Children - 1) Classic triad of dysuria, frequency and abdominal/loin pain, 2) haematuria, 3) offensive/cloudy urine (pyuria), 4) fever/nausea + vomiting
Upper tract (pyelonephritis) - fever, malaise, vomiting, loin/abdominal pain (older), failure to thrive and jaundice. Lower tract (cystitis) - dysuria, frequency, lower abdominal pain, urgency, incontinence, haematuria
Ddx? Appendicitis, gastroenteritis
Diagnosis of UTI (urine)?
When to take urine sample:
1) Symptoms and signs of UTI
2) Unexplained fever of 38 degrees C
3) Alternative site of infection but remain unwell
All infants younger than 3 months with suspected UTI should be referred to paediatric specialist and urine should be sent for urgent microscopy (not dipstick) and culture.
Urine sample:
- Mid-stream sample GOLD STANDARD
- Child in nappies - ‘clean catch’ - wait for child to urinate in ‘clean’ pot, OR adhesive plastic bag attached to perineum after careful washing can be used - risk of contamination with skin flora.
- Urethral catheter there is urgency in obtaining sample.
- Suprapubic aspirate (SPA) - fine needle attached to syringe instead directly into bladder just above symphysis pubis under ultrasound guidance. Only in severely ill infants requiring urgent diagnosis and treatment. (invasive)
Urine analysis:
- Analyse as soon as taken, otherwise refrigerate
- Urine dipstick OVER 3 months - nitrite stick testing and leucocyte esterase testing.
- Microscopy + Culture + Sensitivity (MCS):
Pyuria +ve and Bacteria +ve = UTI
Pyuria -ve + Bacteria +ve = UTI
Pyuria +ve + Bacteria -ve = treat for UTI if symptomatic
Both -ve = NO UTI
Diagnosis of UTI (imaging)?
Imaging only warranted for <6m or no response Abx or atypical UTI.
1) Ultrasound - identifies structural defects + obstructions - not commenced if response to Abx within 48hrs unless pt is <6m or has atypical UTI
2) DMSA scan - renal function/presence of renal scarring
3) MCUG - detect VUR or obstruction
4) Atypical UTI - seriously ill/septicaemia, poor urine flow, abdominal/bladder mass, lack of response to Abx within 48hrs, infection with non E.coli organism
Treatment of UTI?
<3m: Immediate hospital admission and Abx e.g. IV Cefotaxime until fever settled.
> 3m and children: Consider hospital admission, upper - - —- UUTI/pyelonephritis (bacteriuria + fever >38degrees or bacteriuria + loin pain without fever): Oral antibiotics e.g. co-amoxiclav
- LUTI/cystitis: Oral antibiotics e.g. Trimethoprim or Nitrofurantoin
Prevention of UTI?
1) High fluid intake (high urine production), regular voiding, good perineal hygiene, prevent/treat constipation
2) Antibiotic prophylaxis in those <2 years with; congenital abnormality of kidneys or urinary tract or upper UTI or severe reflux: Trimethoprim or Nitrofurantoin (Oral)
If renal scarring is present or reflux seen on investigation (MCUG), or recurrent UTI then consider antibiotic prophylaxis + monitor blood pressure, renal growth and function
