Renal Flashcards
What is oedema?
Increase in interstitial fluid
Swelling, pitting oedema, facial puffiness, ascites, pleural effusions, pulmonary oedema
What can cause oedema?
Lymph drainage problems (lymphoedema) - congenital/blockage
Venous drainage and pressure problems - venous obstruction (eg venous thrombosis)
Lowered oncotic pressure - low albumin/protein
Salt and water retention
What can cause lowered oncotic pressure?
Malnutrition
Decreased production - liver
Increased loss - gut/kidney (nephrotic syndrome)
What can cause salt and water retention?
Kidney impaired GFR
Heart failure
What is nephrotic syndrome?
Damaged podocytes leading to loss of protein through podocyte processes
What is the classic triad of symptoms in nephrotic syndrome?
Heavy proteinuria (frothy urine)
Hypoalbuminaemia
Oedema
How is protein level determined in nephrotic syndrome investigations?
Urine dipstick - semi-quantitative levels
First morning urine protein:creatinine
What levels of protein show nephrotic syndrome?
No definite level that is nephrotic
- Normal < 20mg/mmol
- > 600mg/mmol likely to produce hypoalbuminaemia but occurs at lower levels
What is hypoalbuminaemia?
Normal range 35-45g/L
Fluid retention and oedema usually with albumin < 25-30g/L but not strict cut off
Serum albumin linked to fluid retention
Other protein losses responsible for other complications eg infection, thrombosis
What is the oedema in nephrotic syndrome like?
Pitting oedema
Gravitational
What are the 3 types of nephrotic syndrome?
Congenital NS < 1 year
Steroid sensitive NS
Steroid resistant NS
What are the symptoms of steroid sensitive NS?
Normal BP No macroscopic haematuria Normal renal function No features to suggest nephritis Respond to steroids Minimal change on histology
In whom is steroid sensitive NS more common?
Peak age of onset 2-5
M > F
Higher incidence in those from African sub-continent
What causes steroid sensitive NS?
? Immunological aetiology
What is the prognosis of steroid sensitive NS?
Recurrent relapses in 80%
- Of these 50% have frequent relapses - problems associated with steroid usage over prolonged periods of time
5% continue into adult life
Normal renal function if steroid responsive
How is steroid sensitive NS treated?
Standard course of prednisolone for first episode - 60mg/m2 for 4 weeks, then 40mg/m2 on alternate days for 4 weeks
Other considerations - Na and water moderation, diuretics, penicillin as can get very unwell with infection, measles and varicella immunity and pneumococcal immunisation
What are the symptoms of steroid resistant NS?
Elevated BP Haematuria Impaired renal function Features may suggest nephritis Failure to respond to steroids Histology - various underlying glomerulopathy, basement membrane abnormalities
What is acute glomerulonephritis?
Inflammation of kidneys
Haematuria (macroscopic), proteinuria (varying degree), impaired GFR, salt and water retention
What does impaired GFR lead to?
Rising creatinine
Salt and water retention
What does salt and water retention lead to?
Hypertension
Oedema
What often causes acute glomerulonephritis?
Post-streptococcal infection
Often nasopharnygeal or skin infection
Group A beta-haemolytic strep nephritogenic strains
Antigen-antibody complexes form in glomerulus causing complement activation and glomerular injury
When does nephritis happen post infection?
Around 10 days
What are the signs of clinical nephritis?
Haematuria - swelling, decreased urine output
Oedema, hypertension, signs of CVS overload
How is acute glomerulonephritis managed?
Fluid balance - measurement of input and output, fluid moderation, diuretics, salt restriction
Correction of other imbalances - K+, acidosis
Dialysis if needed (uncommon)
Penicillin - treatment of strep infection
What is the prognosis of glomerulonephritis?
95% full recovery
Not recurrent
No long term implication of renal function if full recovery
What investigations should you do for acute glomerulonephritis?
FBC - mild, normochromic normocytic anaemia
U&Es - increased urea and creatinine, hyperkalaemia, acidosis
Immunology - raised ASOT/anti-DNAse B titre, low C3/4
Throat/other swabs
Urinalysis - haematuria (macroscopic), proteinuria, microscopy (RBC cast)
What are the different causes of AKI?
Pre-renal
Renal
Post-renal
What is Henoch-Schonlein purpura?
Clinical diagnosis based on rash - purpuric rash - red raised rash over legs and/or buttocks
Vasculitis affecting several organs
What organs does HSP affect?
Skin
Joints
Gut
Kidneys
What are the symptoms of HSP?
Rash - purpuric Arthritis Abdominal pain Faecal blood Proteinuria and haematuria
What affect can HSP have on the kidneys?
Haematuria/proteinuria Nephrotic syndrome Acute nephritis Renal impairment Hypertension
Why does HSP caused nephritis?
IgA deposition
What type of nephrotic syndrome can HSP cause?
Either steroid sensitive/resistant
If resistant then may need alternative immunosuppression and/or other anti-proteinuric measures
What is the prognosis of HSP?
Variable
May be ESRD
What should you do with a child who has had HSP?
Monitor bloods and urine after diagnosis to check for kidney problems
What is a UTI?
Infection of the urinary tract with growth of bacteria within the urinary tract 10^5 organisms/ml growth on culture
2 types - acute pyelonephritis (upper), acute cystitis (lower)
How common are UTIs in children?
3-5% girls and 1-2% boys Can cause significant acute illness 50% rate of recurrence 50% structural abnormality presenting symptom Heavy burden on NHS and families
What are the long term complications of UTI in children?
Kidney scarring
Hypertension
CKD
What are the common symptoms and signs in infants < 3 months with UTI?
Fever, vomiting, lethargy, irritability
Less commonly - poor feeding, failure to thrive
Even less commonly - abdominal pain, jaundice, haematuria, offensive urine
What are the common symptoms and signs of UTI in preverbal children > 3 months?
Fever
Less commonly - abdominal pain, loin tenderness, vomiting, poor feeding
Even less commonly - lethargy, irritability, haematuria, offensive urine, failure to thrive
What are the common symptoms and signs of UTI in verbal children?
Frequency, dysuria
Less commonly - dysfunction voiding, changes to continence, abdominal pain, loin tenderness
Even less commonly - fever, malaise, vomiting, haematuria, offensive urine, cloudy urine
When should you take a urine sample from a child?
With S&S of UTI
With unexplained fever > 38
With alternative site of infection but who remain unwell
All infants < 3 months with suspected UTI referred to paediatric specialist care and urine should be sent for M & C
How do you collect a urine sample from a child?
MSU if able to urinate on command
Clean catch recommended method
Urine collection pads
Catheter sample/suprapubic aspiration - before SPA need USS guidance to demonstrate presence of urine in bladder
Don’t delay treatment to seriously ill children for urine sample
Need to specify how urine was collected
How can you do urine analysis?
Visual inspection
Dipstick - nitrites, leucocyte esterase
M, C & S
How do you interpret microscopy results?
Bacteruria and pyuria positive - regarded as having UTI
Bacteruria positive, pyuria negative - regarded as having UTI
Bacteruria negative and pyuria positive - antibiotic treatment only commenced if clinically UTI (could be partially treated UTI)
Bateruria and pyuria negative - UTI excluded
10^5 organisms/ml of single bacteria on clean catch/MSU OR any growth on SPA
What is the most common type of bacteria causing UTI?
E coli
Proteus - more common in boys
What bacteria may indicate structural abnormality?
Pseudomonas
Which children need admission for IV antibiotics?
< 3 months - any child
Systemically unwell
Significant risk factors
How do you treat an infant < 3 months that is systemically well?
Minimum 2-4 days IV antibiotics followed by oral for 3 days
Advice to return if no better at 24-48 hours for reassessment
How do you treat an infant < 3 months that is systemically unwell (fever > 38 +/- loin pain/tenderness)?
Minimum 2-4 days IV antibiotics followed by oral 7-10 days (consider IV according to clinical judgement - use lower threshold for IV antibiotics in younger children, those with significant risk factors and severly ill)
What constitutes an atypical UTI?
Septicaemia/requires IV antibiotics Non-E coli UTI Poor urine flow Abdominal mass/bladder mass Raised creatinine Failure to respond to treatment with suitable antibiotics within 48 hours
What constitutes a recurrent UTI?
2/more UTI episodes at least one episode with systemic S&S
3/more UTI without systemic S&S
When should you investigate further for structural abnormalities or scarring/damage to kidneys?
Atypical or recurrent UTI
What is the first line investigation for a UTI?
USS of renal tract
- Non-invasive
- Observer dependent
- Size and drainage of kidneys and bladder
- Good for ?obstruction
What is the second line investigation after USS for UTI and when do you do it?
Micturating cystourethrogram (MCUG)
- Done if abnormalities detected on USS
- Vesicoureteric reflux - retrograde flow of urine from bladder into ureter/pelvicalyceal system/intrarenal, severity graded on level of reflux and associated dilatation, I-V - IV and V most severe with urine backing up into kidneys, associated with UTI/renal abnormalities
- Bladder
- Posterior urethra
What is the third line investigation for UTI after USS and MCUG?
DMSA scan - dimercaptosuccinic acid
- Radionuclide imaging
- Relative renal function of each kidney
- Renal scarring and extent of scarring
When should you give children a general paediatric follow up appointment?
All children < 3 months
Children of any age systemically unwell
Children with recurrent UTI
Address dysfunctional elimination syndromes and constipation
Include height, weight, BP and routine testing for proteinuria
Name 2 possible causes of UTI
E coli Enterobacter Klebsiella Proteus Pseudomonas Enterococcus
Name 2 antibiotics you could use to treat UTI
Trimethoprim
Amoxicillin
Cephalosporin
(Nitrofurantoin)
What further investigations could you do in a child with UTI?
USS of urinary tract depending on age
DMSA if atypical
MCUG if atypical or doesn’t respond to treatment
What does USS of urinary tract tell you?
Structural abnormalities
What does DMSA scan tell you?
Function and location of kidneys
What does MCUG tell you?
Shows how well bladder functions
What factors affect your choice of investigation in UTI?
Age of child
- < 6 months, 6 months to 3 years, > 3 years
Recurrent/atypical infection
How well responds to treatment
What are the causes of proteinuria in children?
Non-pathological - Transient - Fever - Exercise - UTI Orthostatic - checking at the end of the da and stood upright Pathological - Nephrotic syndrome - CKD - Glomerulonephritis - Tubular interstitial nephritis
What is the diagnostic criteria for nephrotic syndrome?
Heavy proteinuria > 3+
Urine protein/creatinine ratio > 250mg/mmol
Hypoalbuminaemia < 20g/l
What initial investigations do you have for nephrotic syndrome?
BP
Urine dip - protein + blood, protein:creatinine ratio
24 hour urine collection
Urine microscopy
FBC, clotting, ESR, U&E, albumin, cholesterol, blood glucose, bone profile, chicken pox status
What are the possible causes of nephrotic syndrome?
Minimal change disease > 90%
Focal segmental glomerulosclerosis
Membranous glomerular disease
Membranous nephropathy
How would you treat nephrotic syndrome?
Prednisolone 60mg/m2 for 4 weeks then wean Maintenance pred PPI cover Low salt diet Penicillin V + imms Antihypertensives Fluid balance
What is the prognosis of nephrotic syndrome?
Most respond to steroids - 80%
50% recurrent relapse
0.5-1% mortality
