Kidneys and Urinary Tract Disorders Flashcards
Define acute glomerulonephritis
Acute inflammation of the kidneys
What is the pathophysiology of acute glomerulonephritis?
o Increased glomerular cellularity (proliferative disease) restricts glomerular blood flow →GFR is decreased
o This leads to
▪ Decreased urine output and volume overload
▪ Hypertension (may cause seizures)
▪ Oedema (usually initially periorbital)
▪ Haematuria and proteinuria
What are the causes of acute nephritis in children?
PAVI
o Post-infectious (including streptococcus)
o Vasculitis
▪ Henoch-Scholein purpura
▪ SLE
▪ Wegener granulomatosis
▪ Microscopic polyarteritis
▪ Polyarteritis nodosa
o IgA nephropathy and mesangiocapillary glomerulonephritis
o Anti-glomerular basement membrane disease (Goodpasture syndrome)
Define rapidly progressive glomerulonephritis.
Rarely you may get rapid deterioration of renal function
o This can occur with any cause of acute nephritis
o If untreated, this could lead to CKD
What are the signs and symptoms of glomerulonephritis?
- presence of risk factors
- haematuria
- oedema
- hypertension
- oliguria
- anorexia
- nausea
- malaise
- group A beta-haemolytic Streptococcus
- respiratory infections
- gastrointestinal infections
- hepatitis B
What are the investigations for glomerulonephritis?
- urinalysis and urine microscopy
- comprehensive metabolic profile
- glomerular filtration rate (GFR)
- full blood count
- erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)
- complement levels
- rheumatoid factor
- anti-neutrophil cytoplasmic antibody
How do you manage acute glomerulonephritis?
-
Mild:
- Treat the underlying cause
- Supportive tx with close monitoring
- May need abx, if post-strep GN
- Phenoxymethylpenicillin
-
Moderate:
- ACE inhibitor or ARB
- May need abx, if post-strep GN
- Phenoxymethylpenicillin
- Furosemide
-
Severe:
- Corticosteroids + immunosuppressants (e.g. Rituximab)
-
With nephrotic syndrome:
- Prednisolone +/- immunosupressant
- Prophylactic Trimethoprim - for early phases of tx due to immunosuppression
How do you manage Rapidly progressive glomerulonephritis?
-
Manage existing CV RFs:
- Lifestyle
- Blood
- BP control
- Aspirin
-
For Anti-GBM
- Plasmapheresis + prednisolone + cyclophosphamide
- Prophylactic Trimethoprim: for early phases of treatment due to immunosuppression
-
For immune complex - not SLE:
- Prednisolone
- Phenoxymethylpenicillin
-
For immune complex - SLE:
- Cyclophosphamide +/- prednisolone
- Prophylactic Trimethoprim: for early phases of treatment due to immunosuppression
-
For Pauci-immune:
- Methylprednisolone + cyclophosphamide
- Prophylactic Trimethoprim: for early phases of treatment due to immunosuppression
Define post-streptococcal and post-infectious nephritis.
• Usually follows streptococcal sore throat or skin infection
o Characteristically occurs 4-6 weeks following group A beta-haemolytic streptococcus (GAS) infection (skin or throat) (Strep pyogenes)
What is the pathophysiology of post-streptococcal/post-infectious nephritis?
• Thought to be due to deposition of immune complexes in glomeruli
o Type III hypersensitivity reaction→immune complex deposition (IgG, IgM) in glomerular membrane→leads to inflammatory reaction in glomerulus
o Involves C3 complement activation and depletion
Note: to differentiate between this and IgA nephropathy – think how long after pharyngitis, they have had symptoms of glomerulonephritis
Common in developing countries
What are the clinical features of post-streptococcal/post-infectious nephritis?
- Coca-cola coloured urine (Dark)
- Peripheral oedema
What are the ix for post-streptococcal/post-infectious GN?
o Evidenceofrecentstreptococcalinfection
▪ Culture of the organism
▪ Anti-streptolysin O titre
• Detects most strains of group A streptococcus
▪ Anti-DNAse B titres
• Also detects group A beta-haemolytic streptococci
o Low complement (C3) levels
▪ Return to normal after 3-4 weeks
What is the mx of post-streptococcal/post-infectious GN?
Same as acute nephritis.
Define IgA nephropathy.
Defined by the presence of mesangial IgA immune deposits, often accompanied by C3 and IgG. Also known as Berger’s disease.
Common
Involves type III hypersensitivity reaction (IgA-IgG complex)
Usually occurs 5-7 days following an upper RTI (pharyngitis) or GI infection
Prognosis in children better than in adults
What are the clinical features of IgA nephropathy?
• Presents with MACROSCOPIC HAEMATURIA (urine appears red) in association with upper respiratory tract infection
What are the ix for IgA nephropathy?
Urinalysis: RBCs, protein
C3 and C4 complement levels: normal
Renal biopsy: diffuse mesangial IgA deposition (same as HSP)
What is the Mx of IgA nephropathy?
Same as HSP.
Most cases will resolve spontaneously within 4 weeks
Admit if inability to maintain adequate hydration with oral intake, severe abdominal pain, severe renal involvement etc
o If dehydrated→IV fluids
o If significant anaemia→may need RBC transfusion
Joint pain can be managed using paracetamol or ibuprofen
If there is scrotal involvement or severe oedema or severe abdominal pain, oral prednisolone may be given - also rest, hydration, and elevation of affected area
IV corticosteroids are recommended in patients with nephrotic-range proteinuria and those with declining renal function
In rapidly progressive nephritis: IV corticosteroid + oral prednisolone + cylophosphamine - renal transplant and dialysis may be considered.
Renal transplant may be considered in end-stage renal disease
Follow up for BP and renal function
Define Familial Nephritis.
Alport syndrome is the MOST COMMON familial nephritis
X-linked recessive disorder
Leads to progressive end-stage chronic kidney disease in early adult life
Associated with sensorineural deafness and ocular defects
Thin basement membrane disease is a differential
Define AKI.
Acute kidney injury (AKI) is a sudden, potentially reversible, reduction in renal function. Oliguria (<0.5 ml/kg per hour) is usually present.
How are AKIs stratified in terms of level of severity?
It is stratified into levels of severity by the pRIFLE and KDIGO criteria, two of the most widely used diagnostic criteria for AKI. pRIFLE uses changes in estimated creatinine clearance (eCCl), KDIGO uses serum creatinine (SCr) and changes in urine output.
What are the causes of AKIs?
The cause(s) of acute kidney injury may be:
prerenal: the most common cause in children
renal: there is salt and water retention; blood, protein, and casts are often present in the urine; and there may be symptoms specific to an accompanying disease (e.g. haemolytic uraemic syndrome [HUS])
postrenal: from urinary obstruction.
What are the pre-renal causes of AKIs?
- Hypovolaemia:
- gastroenteritis
- burns
- sepsis
- haemorrhage
- nephrotic syndrome
- Circulatory failure
- Heart failure
This is suggested by hypovolaemia. The fractional excretion of sodium is very low as the body tries to retain volume.
What are the renal causes of AKIs?
- Vascular:
- haemolytic uraemic syndrome
- vasculitis
- embolus
- renal vein thrombosis
- Tubular:
- acute tubular necrosis
- ischaemic
- toxic
- obstructive
- Glomerular
- Glomerulonephritis
- Interstitial
- Interstitial nephritis
- Pyelonephritis
If there is circulatory overload, restriction of fluid intake and challenge with a diuretic may increase urine output sufficiently to allow gradual correction of sodium and water balance. A high-calorie, normal protein diet will decrease catabolism, uraemia, and hyperkalaemia
What are the post-renal causes of AKI?
Obstruction:
congenital, e.g. posterior urethral valves
acquired, e.g. blocked urinary catheter, renal and ureteric stones
When is acute-on-chronic renal failure suggested?
Acute-on-chronic renal failure is suggested by the child having faltering growth, anaemia, and disordered bone mineralization (renal osteodystrophy).
What are the clinical features of AKI?
Non-specific symptoms such as sepsis, hypotension, decreased urine output, lower urinary tract symptoms or oedema
Acute-on-chronic renal failure is suggested by:
o Growth failure
o Anaemia
o Disordered bone mineralisation (renal osteodystrophy)
What are the investigations for AKI?
Serum creatinine
Urine output
GFR
KDIGO criteria or pRIFLE
What are the investigations for AKI?
Serum creatinine
Urine output
GFR
KDIGO criteria or pRIFLE
What is the management of an AKI?
- Use STOP AKI
- Sepsis - perform a septic screen
- Toxins - identify and stop nephrotoxic drugs (e.g. NSAIDS, amino glycoside. iodine based contrast agents)
-
Optimise volume status and BP
- Hypovolaemic - give bolus saline
- Withhold diuretics
-
Prevent harm
- Treat reversible causes e.g. urinary tract obstruction
- Treat life threatening complications e.g. acidosis and hyperkalaemia
Pre-renal failure
o Due to hypovolaemia, decreased sodium excretion because the body is trying to retain it
o Hypovolaemia should be urgently addressed with fluid replacement and circulatory support
o Dopamine/adrenaline in severe hypotension
o Furosemide if volume overloaded
What is the prognosis of AKI?
AKI in childhood generally has a good prognosis unless it is complicating a more serious condition (e.g. severe infection, following cardiac surgery)
How do you manage metabolic abnormalities in a renal-AKI?
How common are UTIs?
Affects 3-7% of girls and 1-2% of boys before age of 6 years
o More common in boys until 3 months of age (dye to congenital abnormalities) and then much more common in girls
12-30% of them have recurrence within a year
What systems are involved in UTIs?
May involve kidneys (pyelonephritis) - fever and systemic involvement
or cystitis - no fever
Why are UTIs important in childhood?
Up to half of those affected have a structural abnormality of the urinary tract
Pyelonephritis
o Involves kidneys
o Associated with fever and systemic involvement
o May damage the growing kidney and form a scar, predisposing to hypertension and progressive CKD if scarring is bilateral
What are the causative organisms of UTIs?
o Escherichia coli–most common (80%)
o Klebsiella
o Proteus
▪ More common in boys
▪ Predisposes to formation of phosphate stones (as it alkalises urine)
o Pseudomonas
▪ Suggests that there may be some structural abnormality in urinary tract
▪ More common in children with plastic catheters or ureteric stents
o Enterococcus faecalis
What are the RFs of getting a UTI?
o Antenatally diagnosed renal or urinary tract abnormality
o Incomplete bladder emptying due to infrequent voiding, vulvitis, hurried micturition, obstruction by a loaded rectum via constipation, neuropathic bladder
o Vesicoureteric reflux (found in 35% of children presenting with UTI)
o Poor hygiene e.g. not wiping from front to back in girls
What are the clinical features of UTIs in infants?
Infants: non-specific symptoms
o Fever
o Vomiting
o Lethargy/irritability
o Poor feeding/faltering growth
o Jaundice
o Septicaemia
o Offensiveurine
o Febrile seizure (> 6 months)
What are the clinical features of UTIs in children?
o Dysuria, frequency, urgency
o Abdominal pain or loin tenderness
o Fever+/-rigors
o Lethargy and anorexia
o Vomiting, diarrhoea
o Haematuria
o Offensive/cloudy urine
o Febrile seizure
o Recurrence of enuresis
What are the immediate investigations used for a UTI?
• Test urine sample in any infant/child presenting with
o Unexplained fever > 38 degrees
o An alternative site of infection who remain unwell despite treatment o Symptoms and signs suggestive of UTI
o Collection of urine samples
▪ Children in nappies
BEST METHOD: a ‘clean-catch’ sample into a waiting clean pot when nappy is removed
If not possible, use urine collection pad
Adhesive plastic bag applied to perineum after careful washing (possible contamination)
Urethral catheter if urgent, and no urine is passed
Suprapubic aspiration (fine needle attached to syringe inserted directly into a bladder under US guidance) if severely ill and non-invasive methods not possible
▪ Older children
• MIDSTREAM SAMPLE, with careful cleaning and collection to avoid contamination
o Send sample for microscopy and culture
▪ A bacterial culture of > 105 colony-forming units (CFU) of a single organism per millilitre in a properly collected specimen gives a 90% probability of infection
▪ If mixed growth of organisms→suggests contamination
Urine dipstick
o Can be used as screening test
o Culture should still be performed unless both leucocyte esterase and nitrite are negative, or is clinical symptoms and dipstick tests do not correlate
o Assess risk of serious illness (ABCDE)
▪ Temperature
▪ Respiratory rate
▪ Heart rate
▪ Do not delay treatment in a child with high risk of serious illness if urine sample cannot be obtained
▪ Capillary refill time
▪ Check for signs of dehydration
What further investigations would you do for a UTI?
The extent of further investigation beyond urine sample is controversial as they can be invasive
o There has been a move away from extensive investigation of all children with UTIs to those with atypical or recurrent UTIs
o Atypical UTIs include
▪ Seriously ill or septicaemia
▪ Poor urine flow
▪ Abdominal or bladder mass
▪ Raised creatinine
▪ Failure to respond to suitable antibiotics within 48 hours
▪ Infection with atypical organisms
o An initial ultrasound will identify serious structural abnormalities and urinary obstruction and renal defects
o If urethral obstruction is suspected, MCUG should be performed promptly
o NOTE: functional scans should be deferred for 3 months after a UTI, unless the ultrasound is suggestive of obstruction, to avoid missing a new scar and because false-positive results may be produced due to transient inflammation o NICE guidelines on further investigations:
▪ Infants and children with atypical UTI should have an ultrasound of the urinary tract to identify structural abnormalities
▪ DMSA and MCUG may also be performed in children < 6 months presenting with atypical or recurrent UTI
DMSA to check for renal scars 3 months after UTI
MCUG or MAG3 to detect obstruction and VUR
How do you interpret a urine dipstick and how does this change your management (in <3 yrs and ≥3yr old)?
If both leucocyte esterase + nitrite positive: treat as UTI (+ send urine for culture if < 3 years, suspicion of pyelonephritis, no response to treatment etc)
If both leucocyte esterase + nitrite negative: UTI unlikely, consider DDx
If leucocyte esterase positive + nitrite negative:
o Send urine sample for microscopy and culture
o If < 3 years: start antibiotic treatment
o If > 3 years: only start abx if good clinical evidence of UTI
• If leucocyte esterase negative + nitrite positive: treat as UTI
o Start abx if dipstick was with a fresh urine sample
o Send urine for culture to confirm
Summarise the investigations and management of UTIs (taking into account age)
What abx and for how long do we use for UTIs (special consideration for age)
Define enuresis.
Definition: normal micturition occurring at an inappropriate or socially unacceptable time or place, occurring after a developmental age when bladder control should be established (~5 years)
At what age do we expect children to be dry by:
- Day and night
- By day only
- Day and night: 5 yr
- Day only: 4 yrs
Define primary nocturnal enuresis.
nocturnal enuresis in which the child has never had a period of dryness longer than 6 months
What is the management of minimal change disease?
Describe Stage 1 to 5 CKD.
What are the 1st line, 2nd line and additional treatments for CKD?
