Nephrology Flashcards
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
What does enuresis mean?
Involuntary urination.
What is the term for bed wetting?
Nocturnal enuresis.
What is the inability to control bladder function during the day called?
Diurnal enuresis.
What is the normal age for children to get control of daytime urination?
2 years.
What is the normal age for children to get control of night time urination?
3-4 years
What is Primary Nocturnal Enuresis?
Where the child has never managed to be consistently dry at night.
What is the most common cause of Primary Nocturnal Enuresis?
Variation on normal development, particularly if the child is <5 years old.
Family history of delayed dry nights.
- important to reassure, no need for further investigations/management
What are other causes of primary nocturnal enuresis?
1) Overactive bladder (frequent small volume urination prevents development of bladder capacity)
2) Fluid intake prior to bedtime (fizzy drinks, juice, caffeine have diuretic effect)
3) Failure to wake due to deep sleep and underdeveloped bladder signals
4) Psychological distress (low self-esteem, pressure/stress at home/school)
5) Secondary causes e.g. chronic constipation, cerebral palsy, learning disability, UTI
How is Primary Nocturnal Enuresis managed?
1) Establish underlying cause - 2 week diary of toileting, fluid intake, bedwetting episodes; good history and examination to exclude physical/psychological causes
2) Reassure parents of children <5 years that likely to resolve without treatment
3) Lifestyle changes e.g. reduce fluid intake in evenings, pass urine before bed, easy access to toilet
4) Encouragement and positive reinforcement (avoid blame/shame/punishment)
5) Treat underlying causes/exacerbating factors e.g. constipation
6) Enuresis alarms (sensor wakes child if wet)
7) Pharmacological treatment
What is Secondary Nocturnal Enuresis?
Where a child begins wetting the bed when they have previously been dry for at least 6 months.
More indicative of underlying illness than primary enuresis.