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
What are the investigations for nephrotic syndrome?
Urine protein - test strips, dipstick FBC, ESR Urea, electrolytes, creatinine and albumin Complement levels - c3, c4 Antistreptolysin O, anti-DNAse Urine microscopy and culture Urinary sodium conc Hep B and C, malaria
What is steroid sensitive nephrotic syndrome and its features?
The proteinuria resolves with corticosteroid therapy
Do not progress to renal failure
Age between 1-10 No macroscopic haematuria Normal blood pressure Normal complement levels Normal renal function
What is the management of steroid resistant nephrotic syndrome?
Referral to paediatric nephrologist
Management of oedema with diuretic therapy, salt restriction, ACE inhibitors
Sometimes NSAIDs to reduce proteinuria
What are some of the complications of nephrotic syndrome?
Hypovolaemia - complains of abdominal pain and feels faint, peripheral vasoconstriction and urinary sodium retention.
Thrombosis due to urinary losses of antithrombin
Can be exacerbated by steroid therapy
Infection - children in relapse at risk of infection with capsulated bacteria esp. pneumococcus
Spontaneous peritonitis may occur
Vaccinations needed
Chickenpox and shingles treated with aciclovir
Hypercholesterolaemia
What are the causes of haematuria?
Non glomerular -
Infection (bacteria, viral, TB, schistosomiasis)
Trauma to genitalia, urinary tract or kidneys
Stones, tumours, sickle cell
Bleeding disorders
Renal vein thrombosis
Hypercalciuria
Glomerular -
Acute glomerulonephritis, with proteinuria
Chronic glomerulonephritis with proteinuria
IgA nephropathy
Familial nephritis e.g. Alport
Thin basement membrane disease
What is the most common cause of haematuria in paeds?
Urinary tract infection
When might a renal biopsy be indicated?
Significant persistent proteinuria
Recurrent macroscopic haematuria
Renal function abnormal
Complement levels persistently abnormal
What are the investigations for haematuria?
Urine microscopy with phase contrast, culture
Protein and calcium excretion
Kidney and USS urinary tract
Plasma urea, electrolytes, creatinine, calcium, phosphate, albumin
FBC, platelets, clotting, sickle cell
If indicative of glomerular haematuria: ESR, complement, anti-DNA Throat swab Hep B and C Renal biopsy if indicated Test mother's urine for blood if alport syndrome suspected, and test hearing
What are the causes of acute nephritis?
Post infections, including streptococcus
Vasculitis - Henoch-Schonlein purpura or rarely SLE, Wegener’s
IgA nephropathy
Anti glomerular basement membrane disease - Goodpasture’s
When might glomerular haematuria be more likely?
Brown urine, the presence of deformed red cells and casts, and proteinuria
What is post strep and post infectious nephritis?
Usually follows strep throat or skin infection
Evidence of recent strep infection
Low complement C3 returns to normal after 3-4 weeks
Hx of e.g. tonsillitis, positive throat swab, anti-streptolysin antibody titres
Management is supportive,
may need antihypertensives and diuretics if e.g. hypertension and oedema
What is Henoch-Schonlein purpura?
Characteristic skin rash - buttocks, extensor surfaces of arms and legs, ankles
Joint pain and swelling
Abdominal pain - haematemesis and malaena, intussusception
Renal - microscopic/macroscopic haematuria, nephrotic syndrome, glomerulonephritis
What is nephritis?
Inflammation within the nephrons of the kidney
Reduction in kidney function
Haematuria - visible, invisible
Proteinuria
Most common
Post-strep
IgA - Berger’s disease
What occurs in IgA nephropathy?
Henoch-Schonlein purpura - IgA vasculitis
IgA nephropathy is Berger’s
IgA deposits and glomerular mesangial proliferation
Management is supportive treatment and immunosuppressant medications
What are causes of hypertension?
Renal Parenchymal disease Renal artery stenosis PCKD Renal tumours
Coarctation of the aorta
Catecholamine excess e.g. phaeochromocytoma
Endocrine
Congenital adrenal hyperplasia
Cushing’s, hypothyroid
Essential HTN
Diagnosis of exclusion
What can be the presentation of hypertension?
Vomiting Headaches Facial palsy Hypertensive retinopathy Convulsions Proteinuria Failure to thrive and cardiac failure most common in infants
What are causes of palpable kidneys?
Unilateral Multicystic kidney Compensatory hypertrophy Obstructed hydronephrosis Renal tumour - Wilm's
Bilateral
Polycystic kidneys
Tuberous sclerosis
Renal vein thrombosis
What can cause renal stones in childhood?
Uncommon
Predisposing factors e.g. UTI, structural abnormalities, metabolic abnormalities
Commonest are phosphate stones associated with infection
Calcium in idiopathic hypercalciuria
What is Fanconi syndrome?
Generalised proximal tubular dysfunction
Vulnerable to cellular damage
Due to accumulation of cystine, fructose intolerance, Wilson’s, heavy metals, drugs, toxins, Vit D deficient
Leads to excessive urinary loss of amino acids, glucose, phosphate, bicarbonate, sodium, potassium, calcium urate.
What is the presentation of Fanconi syndrome?
polydipsia, polyuria salt deposition, dehydration hypercholraemic met acidosis rickets failure to thrive
What is oliguria?
<0.5ml/kg per hour
What are the causes of AKI?
Sudden potentially reversible reduction in renal function
Prerenal
Hypovolaemia - gastroenteritis, burns, sepsis, nephrotic syndrome
Circulatory failure
Renal
Vascular - haemolytic uraemic syndrome, vasculitis, embolus
Tubular - acute tubular necrosis, ischaemia, obstruction
Glomerular - glomerulonephritis
Interstitial - interstitial nephritis, pyelonephritis
Postrenal
Obstruction - congenital e.g. posterior urethral valves, acquired e.g. blocked catheter
What is the management of prerenal failure?
Correct hypovolaemia
Fractional excretion of sodium will be low as body tries to retain fluid
Correct with fluids
What is the management of renal failure?
If circulatory overload, restrict fluid intake and challenge with diuretic
Renal biopsy to identify any glomerulonephritis as may need immediate treatment with immunosuppression.
What is the management of postrenal failure?
Assessment of site of obstruction
Relief by nephrostomy or bladder catheterisation
What are the indications for dialysis?
Failure of conservative management Hyperkalaemia Severe hypo or hypernatraemia Pulmonary oedema or HTN Severe acidosis Multisystem failure
What is the treatment of metabolic acidosis?
Sodium bicarbonate
What is the treatment of hyperphosphataemia?
Calcium carbonate
Dietary restriction
What is the management of hyperkalaemia?
Calcium gluconate if ECG changes Salbutamol nebulised or iV Calcium exchange resin Glucose and insulin Dietary restriction Dialysis
What is the triad in haemolytic uraemic syndrome?
Acute renal failure
Haemolytic anaemia
Thrombocytopenia - low platelet count
There is thrombosis within small vessels throughout the body
Also reduced urine output Haematuria, dark brown urine Abdominal pain Lethargy and irritability Confusion Oedema HTN Bruising
What is the cause of haemolytic uraemic syndrome?
Bacterial toxin shiga toxin
Most commonly e coli 0157
Antibiotics and anti-motility medications e.g. loperamide to treat gastroenteritis caused by these pathogens increases the risk
Toxin enters gastrointestinal mucosa, localises to endothelial cells of kidney causing intravascular coagulation
Normal clotting cascade, platelets consumed, RBCs damaged - so haemolytic anaemia
What is the treatment of HUS?
Medical emergency
Self limiting and supportive management
Urgent referral for dialysis if needed
Antihypertensives, fluid, blood transfusions if required
What is the threshold of chronic renal failure?
GFR < 15ml/min/1.73m
Congenital and familial causes most common in childhood
What are the clinical features of chronic renal failure?
Anorexia, lethargy
Polydipsia, polyuria
Failure to thrive
Bony deformities from renal osteodystrophy
Hypertension
Acute on chronic renal failure - precipitated by infection or dehydration
Incidental finding of proteinuria
Unexplained normochromic normocytic anaemia
What is the management of chronic renal failure?
Diet - improve nutrition because anorexia and vomiting are common
Protein intake sufficient for normal growth
Prevention of ricks
Phosphate retention and hypocalcaemia due to decreased activation of Vit D leads to secondary hyperparathyroidism, so reduce phosphate intake, calcium carbonate as phosphate binder, and activated Vit D supplements
Control of salt and water balance and acidosis
Treatment with bicarbonate
Recombinant human erythropoietin as there is reduced production, and metabolites that are toxic to bone marrow
Recombinant growth hormone to improve growth due to many hormonal abnormalities
Dialysis, renal replacement therapy in end stages
Minimum weight of 10kg to avoid renal vein thrombosis
Ideally child transplanted before dialysis required, immunosuppression with prednisolone, tacrolimus, azathioprine.
What is the management of nocturnal enuresis?
look for possible underlying causes/triggers (e.g. Constipation, diabetes mellitus, UTI if recent onset) advise on fluid intake, diet and toileting behaviour reward systems (e.g. Star charts). NICE recommend these 'should be given for agreed behaviour rather than dry nights' e.g. Using the toilet to pass urine before sleep
NICE advises: ‘Consider whether an alarm or drug treatment is appropriate, depending on the age, maturity and abilities of the child or young person, the frequency of bedwetting and the motivation and needs of the family’.
Generally:
an enuresis alarm is first-line for children under the age of 7 years
desmopressin may be used first-line for children over the age 7 years, particularly if short-term control is needed or an enuresis alarm has been ineffective/is not acceptable to the family
What is a Wilm’s tumour?
Nephroblastoma
One of most common childhood malignancies
Abdominal mass most common presenting feature
Painless haematuria
Flank pain
Anorexia, fever
Unilateral
Mets found commonly in lung in 20% patients
Management - nephrectomy, chemo, radiotherapy
Good prognosis
What is a posterior urethral valve?
There is tissue at proximal end of urethra - closest to bladder
Causes obstruction of urine output
Creates back pressure into bladders, ureters and up to kidneys causing hydronephrosis
What is the presentation of posterior urethral valves?
Difficulty urinating Weak urinary stream Chronic urinary retention Palpable bladder Recurrent urinary tract infections Impaired kidney function
Severe causes can cause obstruction to outflow in developing fetus - bilateral hydronephrosis and oligohydramnios
Can lead to underdeveloped lungs, resp failure
What are the investigations for posterior urethral valves/
Severe cases picked up on scans
Abdominal ultrasound - enlarged thickened bladder, bilateral hydronephrosis
Micturating cystourethrogram - location of extra urethral tissue and reflux of urine into bladder
Cystoscopy to ablate or remove tissue if possible
What is the management of a posterior urethral valve?
Mild cases observed
Temporary urinary catheter whilst awaiting definitive
Ablation, removal of extra urethral tissue during cystoscopy
What are the types of polycystic kidneys?
Autosomal recessive
Autosomal dominant presents in later life
What are the features of ARPKD?
Cystic enlargement of renal collecting ducts Oligohydramnios Pulmonary hypoplasia Potter syndrome Congenital liver fibrosis
What is the presentation of ARPKD?
Oligohydramnios
Polycystic kidneys on scans
Lack of amniotic fluid leads to Potter syndrome and underdeveloped lungs
What other problems can occur in ARPKD?
Liver failure due to fibrosis Portal hypertension - oesophageal varices Progressive renal failure Hypertension due to renal failure Chronic lung disease
1/3 survive to adulthood
Dialysis
