Nephrology Flashcards
(87 cards)
What are UTIs?
Infections anywhere along the urinary tract pathway including the urethra, bladder, ureters and kidneys.
What is acute pyelonephritis?
Infection affecting the tissue of the kidney.
It may lead to scarring and consequently a reduction in renal function.
What is cystitis?
Inflammation of the bladder; may be a result of a bladder infection.
What may be the only symptom of a UTI in young children?
Fever.
Always exclude/consider a UTI in a child with a temperature unless clear alternative source of infection.
How may babies present with a UTI?
Non-specific symptoms.
- fever
- lethargy
- irritability
- vomiting
- poor feeding
- urinary frequency
How may older infants and children present with a UTI?
More specific symptoms than babies.
- fever
- abdominal pain (particularly suprapubic pain)
- vomiting
- dysuria
- urinary frequency
- incontinence
What features are required to diagnose acute pyelonephritis?
- temperature >38C
- loin pain or tenderness
What key investigation is required if suspect a UTI?
Urine Dipstick
- clean catch sample, avoiding contamination
- involves parent sat with infant without a nappy and a urine pot held ready to catch the sample if it occurs
Midstream urine (MSU) sample to microbiology to be cultured and have sensitivity testing.
What two aspects of a urine dipstick are important for UTI?
Nitrites
Leukocytes
Why are nitrites used as a marker?
Gram negative bacteria (e.g. E.Coli) break down nitrates (a normal waste product in the urine) into nitrites.
The presence of nitrites on a urine dipstick therefore suggests bacteria in the urine.
Why are leukocytes used as a marker?
There are normally a small number of leukocytes in the urine, however a significant rise may indicate infection or another cause of inflammation.
A urine dipstick tests for leukocyte esterase, an enzyme released by leukocytes (neutrophils, macrophages) giving an indication of the number of leukocytes in the urine.
Which of nitrites and leukocytes is the better indication of infection?
Nitrites.
What should be done if only nitrites or only leukocytes or both are found?
Nitrites - worth treating as UTI.
Leukocytes - do not treat as UTI unless there is clinical evidence they have one.
Nitrites & leukocytes - treat as a UTI.
If either are present, send MSU sample to microbiology.
How should a child <3 months with a fever and UTI be managed?
- immediately start IV antibiotics e.g. ceftriaxone
- full septic screen (blood cultures, bloods, lactate)
- consider lumbar puncture
How should a child >3 months with a fever and UTI be managed?
- oral antibiotics (if otherwise well) e.g. trimethoprim, nitrofurantoin, amoxicillin, cefalexin
- features of sepsis or pyelonephritis requires inpatient treatment with IV abx
- Treat pyelonephritis with IV cephalosporin
What investigations can be used for recurrent UTIs?
1) Abdominal USS
2) DSMA Scan
3) MCUG (micturating cystourethrogram)
When should an USS be done for children?
- do abdo USS within 6 weeks in all children <6 months with first UTI (or during illness if recurrent UTIs or atypical bacteria)
- abdo USS within 6 weeks in children with recurrent UTIs
- abdo USS during illness in children with atypical UTI
What is a DMSA scan used for, how does it work, and when should it be done?
Assesses renal scarring (static function).
Use 4-6 months after illness to assess for damage from recurrent or atypical UTIs.
Inject radioactive material (DMSA); use a gamma camera to assess how well the material is taken up by the kidneys.
Where there are patches of kidney that have not taken up the material, this indicates scarring that may be the result of previous infection.
Gives a split function of kidneys - normal would be 50% in each kidney (accept 45-50%)
What is vesico-ureteric reflux (VUR)?
Where urine has a tendency to flow from the bladder back into the ureters.
What does VUR predispose patients to?
Developing upper urinary tract infection and subsequent renal scarring.
How is VUR diagnosed?
Micturating cystourethrogram (MCUG).
How is VUR managed?
Depends on severity.
- avoid constipation
- avoid excessively full bladder
- prophylactic abx
- surgical input from paediatric urology
What can micturating cystourethrograms be used to investigate?
- atypical or recurrent UTIs in children <6 months
- family history of VUR
- dilatation of the ureter on ultrasound
- poor urinary flow
What is involved in a micturating cystourethrogram?
- catheterise child
- inject contrast into the bladder
- take series of xray films to determine whether contrast is refluxing into the ureters (diagnose VUR)
- give prophylactic abx for 3 days around time of investigation