Nephrology and genitourinary 2 Flashcards
Incidence of UTI
3-7% of girls
1-2% of boys
Will have at least one symptomatic UTI by age 6yrs
Importance of UTI in childhood
up to 50% have a structural abnormality of their urinary tract
Pyelonephritis may damage the growinf kidney by forming a scar - if bilateral, it predisposes to HTN and chronic renal failure
Which organisms commonly cause UTI in childhood
Usually bowel flora that enters the urinary tract via the urethra (except newborn - haematogenous)
E.coli is commonest
Klebsiella
Proteus
Pseudomonas (may indicate presence of structural abnormality)
Strep. faecalis
Proteus is commonly in boys - predisposes to phosphate stones
Differentials of haematuria
UTI (bacterial, viral, schistosomiasis, TB)
Glomerular (post-infectious glomerulonephritis, HSP, IgA nephropathy, thin basement membrane or Alport syndrome)
Urinary tract stones (eg. hypercalciuria)
Trauma
Other renal tract pathology (renal tract tumour, polycystic kidney disease)
Vascular (renal vein thrombosis)
Haematological (coagulopathy/sickle cell disease)
Drugs (cyclophosphamide)
Exercise induced
Presenting features of UTI in infants (<3 months)
Non-specific
Commonest to least common:
Fever usually
Vomiting
Lethargy
Irritability
Poor feeding/failure to thrive
Jaundice
Septicaemia
Offensive urine
Haematuria
Presentation of a child with UTI
Dysuria and frequency Abdominal pain or loin tenderness Fever with or without rigors Lethargy Anorexia Vomiting and diarrhoea Haematuria Offensive/cloudy urine Febrile convulsion Recurrence of enuresis
How can urine be collected in a child with nappies?
“clean-catch” sample - into waiting clean pot when nappy is removed. Recommended
Adhesive plastic bag applied to the perineum after careful washing (BUT contamination from the skin)
Urethral catheter if there is urgency in obtaining the sample
Suprapubic aspiration (SPA): fine needle inserted just above the symphysis pubis under US guidance - in severely ill, requiring urgent diagnosis and treatment
Urine sample in an older child
Midstream sample with careful cleaning and collection (white cells and bacteria may contaminate from foreskin)
Relevance of urinary white cells
Not a reliable feature of UTI
May lyse (not present) may be present in febrile children, balanitis or vulvovaginitis
Interpret the results of a urine culture
> 105 colony-forming units of a single organism per milliltre gives 90% chance of infection
Growth of mixed organisms usually indicates contamination
Samples that are taken from catheter or suprapubic aspirate, that show a single organism growth are diagnostic of infection
Interpret dipstick test results
Nitrite stick testing:
positive result is very likely to be UTI
Negative may be false
Leucocyte esterase testing:
May be positive or negative with a UTI
Also positive in febrile illness, balanitis and vulvovaginitis
Action if leucocyte and nitrite both positive
regard as UTI
Action if leucocyte negative and nitrite positive
Start antibiotic treatment
Diagnosis then depends on urine culture
Action if leucocyte positive and nitrite negative
Only start antibiotic treatment if clinical evidence of UTI
Diagnosis depends on urine culture
Action if leucocyte and nitrite both negative
UTI unlikely
Repeat or send urine for culture if history suggests
