Nephrology Flashcards
How can renal function in children be assessed?
Plasma creatinine conc eGFR Inulin Creatinine clearance Plasma urea conc
What radiological investigations can be done?
USS for anatomical assessment
DMSA scan - static scan of renal cortex, detects functional defects e.g. scars but very sensitive
So wait after UTI for 2 months to avoid diagnosing false scars
Micturating cystourethrogram - detects vesicoureteric reflux VUR and urethral obstruction
High radiation dose
MAG3 renogram - dynamic scan, isotope labelled substance excreted
Measures drainage
Plain abdominal x-ray
Identifies unsuspected spinal abnormalities, may identify renal stones
What are the symptoms of a UTI?
Infants - poor feeding, vomiting, irritability
Younger children - abdominal pain, fever, dysuria
Older children - dysuria, frequency, haematuria
Fever, abdo pain, suprapubic pain
Who are UTIs more common in in children?
Boys until 3 months of age due to congenital abnormalities, after which incidence higher in girls
What are the NICE guidelines for checking a urine sample in a child?
If there are any symptoms or signs suggestive of UTI
Unexplained fever of 38 degrees or higher - test urine after 24 hours at latest
With an alternative site of infection but remain unwell
What urine collection methods should be used for a UTI?
Clean catch
If not possible; urine collection pads
Cotton wool balls, gauze, sanitary towels not suitable
Invasive methods e.g. suprapubic aspiration only used if non-invasive methods not possible
What is the management of UTI?
Infants less than 3 months refer to paediatrician
> 3 months with pyelonephritis consider admission to hospital
If not - cephalosporin or co-amoxiclav for 7-10 days
> 3 months with lower UTI treat with oral abx
trimethoprim, nitrofurantoin, cephalosporin, amoxicillin
All children <3 months with fever start immediate IV abx e.g. ceftriaxone and full sepsis screen
Consider LP
How can recurrent UTIs be investigated?
USS
<6 months with first UTI, have abdo USS within 6 weeks or during illness if recurrent/atypical bacteria
Recurrent UTIs - USS within 6 weeks
Atypical UTIs - Abdo USS during the illness
DMSA scan used 4-6 months after illness to assess for damage, inject radioactive material and gamma camera to see how well it is taken up
What is vesico-ureteric reflux?
Where urine flows from bladder back into ureters
Predisposes to upper UTI and subsequent renal scarring
Diagnosed with micturating cystourethrogram
What are the causes of hydronephrosis in children?
Vesicoureteral reflux
Blockage or obstruction at UPJ, UVJ, posterior urethral valves within the urethra, incorrect attachment of the ureter to the bladder - ureterocele or ectopic ureter
Idiopathic, usually resolves on its own before or after birth
What are the symptoms of hydronephrosis in children?
Newborns and infants usually asymptomatic
Pain in side or abdomen
Blood in urine
Older children more likely to present with UTI and symptoms of UTI
What is the management of hydronephrosis?
Close observation before and after birth
Antibiotics
Surgery
Prenatal surgery - place drainage tube in baby’s bladder
What are the symptoms of acute pyelonephritis?
Temperature greater than 38
Loin pain or tenderness
What is nephrotic syndrome?
Basement membrane becomes permeable to protein
What is the presentation of nephrotic syndrome?
Low serum albumin
High urine protein content
Oedema
Frothy urine
Generalised oedema
Pallor
Deranged lipid profile - high cholesterol, triglycerides, low density lipoproteins
High BP
Hyper-coaguability
Most common between the ages of 2-5
What are the causes of nephrotic syndrome?
Most common is minimal change
Secondary to intrinsic kidney disease - focal segmental or membranoproliferative
Secondary to underlying systemic illness - Henoch schonlein purpura, diabetes, infection e.g. HIV, hepatitis, malaria
What is seen in minimal change disease?
Renal biopsy and standard microscopy usually does not detect any abnormality
Urinalysis will show small molecular weight proteins and hyaline casts
What is the management of nephrotic syndrome?
High dose steroids e.g. prednisolone Low salt diet Diuretics to treat oedema Albumin infusions if hypoalbuminaemia severe Abx prophylaxis
High dose steroids given for 4 weeks then gradually weaned over next 8 weeks
Many will relapse, become steroid sensitive
Some may be steroid resistant - give ACEis and immunosuppressants e.g. cyclosporine, tacrolimus and rituximab
What are some of the complications of nephrotic syndrome?
Hypovolaemia due to fluid leaks from intravascular space to interstitial space
Leads to oedema and low BP
Thrombosis because the proteins that usually prevent clotting are lost
And liver responds to low albumin by producing pro-thrombotic proteins
Infection as there is leakage of immunoglobulins
Exacerbated by treatment with steroids
Acute or chronic renal failure
Relapse
What is Potter syndrome?
Intrauterine compression of the fetus due to oligohydramnios caused by lack of fetal urine
Causes characteristic facies:
low set ears, beaked nose
Pulmonary hypoplasia causing resp failure
Limb deformities
Due to bilateral renal agenesis or bilateral multicystic dysplastic kidneys
What is the management of antenatally diagnosed urinary tract anomalies?
Start prophylactic antibiotics
If bilateral hydropnephrosis or dilated urinary tract in a male:
USS within 48h of birth to exclude posterior urethral valves
If normal, stop abx, repeat US in 2-3 months
If abnormal, MCUG, surgery
If unilateral in a male, or any anomaly in a female
USS at 4-6 weeks
If abnormal, further investigations
When is it key to test a urine sample in infants?
Any child with an unexplained fever over 38
What medical measures are suggested for the prevention of UTI?
High fluid intake to produce high urine output
Regular voiding
Ensuring complete bladder emptying by encouraging the child to try a second time
Prevention or treatment of constipation
Good perineal hygiene
Lactobacillus acidophilus probiotic
How should children with recurrent UTIs, renal scarring or reflux be followed up?
Urine culture checks with any non-specific illness
Long term low dose antibiotic prophylaxis
Circumcision considered
Anti-reflux surgery if progression of scarring
BP annual checks
Check renal growth and function if bilateral defects
What is daytime enuresis and its causes?
Lack of bladder control in the day in a child (3-5 years) old enough to be continent
Can also occur in the night
Lack of attention to bladder sensation - development or psychogenic problem - too busy to respond to sensation of full bladder
Detrusor instability - sudden urgent urge to void
Bladder neck weakness
Neuropathic bladder - bladder is enlarged, fails to empty properly
UTI, in absence of other symptoms
Constipation
Ectopic ureter causes constant dribbling, child always damp
What could be seen on investigation of daytime enuresis?
Examination may show neuropathic bladder e.g. distended, abnormal perineal sensation, abnormal leg reflexes
Sensory loss in S2, 3, 4
Girls dry at night but wet on getting up - ectopic ureter opening into vagina
Urine sample - MC&S
USS, urodynamic studies
What is the management of daytime enuresis?
If neurological cause excluded; star charts, bladder training, pelvic floor exercises
Alarm bad to alert when lack of attention to sensation
Treatment of constipation
Anticholinergic drugs e.g. oxybutynin to damp down contractions
What can be the causes of secondary (onset) enuresis?
Loss of previously achieved continence
Emotion upset
UTI
Polyuria from osmotic diuresis in diabetes mellitus or renal concentrating disorder e.g. sickle cell or chronic renal failure
What are some of the investigations of secondary enuresis?
Test urine sample - infection, glycosuria, proteinuria
Assessment of urinary concentrating ability - early morning sample
USS of renal tract
What are some causes of proteinuria in paediatrics?
Orthostatic proteinuria - when child is active and upright during the day
Glomerular abnormalities e.g. minimal change, abnormal glomerular basement membrane
Increased glomerular filtration pressure
Reduced renal mass
HTN
Tubular proteinuria
