Kidney and Urinary Tract Disorders Flashcards
Why are UTI’s important in children?
Up to half of patients have a structural abnormality of their urinary tract.
Pyelonephritis may damage the growing kidney by forming a scar, predisposing to hypertension and to chronic renal failure if the scarring is bilateral
What are some GU anomalies detectable on antenatal US screening?
Absence of both kidneys (renal agenesis) Multicystic dysplastic kidney Pelvic kidney Bladder exstrophy Obstruction to urine flow
What would you see on US if there was absence of both kidneys?
As amniotic fluid is mainly derived from fetal urine, there is severe oligohydramnios resulting in Potter syndrome, which is fatal.
What is multicystic dysplastic kidney?
It results from the failure of union of the ureteric bud (which forms the ureter, pelvis, calyces and collecting ducts) with the nephrogenic mesenchyme. It is a non-functioning structure with large fluid-filled cysts with no renal tissue and no connection with the bladder.
What are some causes of large cystic kidneys?
Multicystic dysplastic kidney
Autosomal recessive polycystic kidney disease
Autosomal dominant polycystic kidney disease
Tuberous sclerosis
How would you assess renal function in children?
Plasma creatinine concentration (main test)
Estimated GFR
Inulin or EDTA GFR
What is Potter syndrome?
Bilateral renal agenesis or bilateral multicystic dysplastic kidney.
Reduced fetal urine excretion.
Oligohydramnios causing fetal compression
What are the clinical features of Potter syndrome?
Facially - low set ears, beaked nose, prominent epicanthic folds and downward slant to eyes.
Pulmonary hypoplasia causing respiratory failure
Limb deformities
What is autosomal recessive polycystic kidney disease?
There is diffuse bilateral enlargement of both kidneys
What is autosomal dominant polycystic kidney disease?
There are separate cysts of varying size between normal renal parenchyma. The kidneys are enlarged
What is pelvic kidney?
When the lower poles are fused in the midline. The abnormal position may predispose to infection or obstruction to urinary drainage
How do you postnatally manage children with antenatally diagnosed anomalies?
Start prophylactic antibiotics, most of them are stopped unless it is a male with bilateral hydronephrosis and/or dilated lower urinary tract after 48h of life, in which case they may require surgery
How come some UTI’s are accompanied by fever?
UTI may involve the kidneys (pyelonephritis) when it is usually associated with fever and systemic involvement, or may be due to cystitis, when there may be no fever
How does a UTI present in infants?
Fever Vomiting Lethargy or irritability Poor feeding/failure to thrive Jaundice Septicaemia Offensive urine Febrile convulsions >6 months old
How does a UTI present in children?
Dysuria and frequency Abdominal pain or loin tenderness Fever with or without rigors Lethargy and anorexia Vomiting, diarrhoea Haematuria Offensive/cloudy urine Febrile convulsion Recurrence of enuresis
What are the main causes of dysuria alone?
Usually due to cystitis, or vulvitis in girls or balanitis in uncircumcised boys.
How can urine be collected in children in nappies?
A clean-catch sample into a waiting clean pot when the nappy is removed.
An adhesive plastic bag applied to the perineum after careful washing, although there may be contamination from the skin
Is a nitrate stick urine test useful in children?
Yes, a positive result useful as very likely to indicate a true UTI
What are the methods of dipstick testing in children?
Nitrate stick testing
Leucocyte esterase stick testing (for WBCs)
What is the likely infected organism in children’s UTI and where does it come from?
It is usually the result of bowel flora entering the urinary tract via the urethra, except in the newborn when it is more likely to be haematogenous.
The commonest organism is E.coli followed by Klebsiella, Proteus an Pseudomonas and Strep. faecalis.
What does Proteus UTI infection predispose to?
To the formation of phosphate stones by splitting urea to ammonia and thus alkalinising the urine
What may Pseudomonas UTI indicate?
It may indicate the presence of some structural abnormality in the urinary tract affecting drainage
What are some contributing factors to incomplete bladder emptying in children?
Infrequent voiding, resulting in bladder enlargement
Vulvitis
Incomplete micturition with residual post-micturition bladder volumes
Obstruction by a loaded rectum from constipation
Neuropathic bladder
Vesicoureteric reflux
What is vesicoureteric reflux?
A developmental anomaly of the vesicoureteric junctions. The ureters are displaced laterally and enter directly into the bladder rather than at an angle, with a shortened or absent intramural course.
What are the causes of vesicoureteric reflux?
It is familial (30-50% of cases)
It may also occur in bladder pathology (neuropathic bladder or urethral obstruction or temporarily after a UTI)
Is vesicoureteric reflux severe?
Its severity varies from reflux into the lower end of an undilated ureter during micturition to the severest form with reflux during bladder filling and voiding, with a distended ureter, renal pelvis and clubbed calyces
Why is vesicoureteric reflux important?
Urine returning to the bladder after voiding results incomplete bladder emptying, which encourages infection.
The kidneys may become infected (pyelonephritis)
Bladder voiding pressure is transmitted to the renal papillae; this may contribute to renal damage
What are the features of an abnormal UTI?
Seriously ill/septicaemia Poor urine flow Abdominal or bladder mass Raised creatinine Failure to respond to suitable antibiotics within 48 hours Infection with non-E.coli organisms
What investigations should you perform in a first UTI?
US of kidneys and urinary tract
DMSA to check for renal scars 3 months after UTI
MAG3 or MCUG to detect obstruction and vesicoureteric reflux
How would you manage UTI in an infant <3 months old?
Refer to hospital immediately where they require IV antibiotics such a cefotaxime
How would you manage an infant >3 months and children with acute pyelonephritis/upper UTI?
Usually treated with oral antibiotics with low resistance patterns (co-amoxiclav for 7-10 days)
How would you manage children with cystitis/lower UTI?
Oral antibiotics for 3 days
What are some medical measures for prevention of UTIs?
High fluid intake to produce a 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 (a probiotic)
How should you follow up children with recurrent UTIs, renal scarring or reflux?
Urine culture with any non-specific illness
Long term, low dose antibiotic prophylaxis can be used
Circumcision in boys may sometimes be considered.
Anti-reflux surgery may be indicated if there is progression of scarring with ongoing reflux.
Blood pressure should be checked annually
Regular assessment of renal growth and function
What is daytime enuresis?
Lack of bladder control during the day in a child old enough to be continent (3-5 years). Nocturnal enuresis is also usually present.
What may cause daytime enuresis?
Lack of attention to bladder sensation Detrusor instability (sudden, urgent order to void induced by sudden bladder contractions) Bladder neck weakness A neuropathic bladder UTI Constipation An ectopic ureter
What is a neuropathic bladder?
The bladder is enlarged and fails to empty properly, irregular thick wall and is associated with spina bifida and other neurological conditions
What is likely to be the cause of girls who are dry at night but wet on getting up?
Pooling of urine from an ectopic ureter opening into the vagina
What may you see on investigated daytime enuresis?
Urine sample: UTI
US: bladder pathology (imcompltete emptying or thickening of the bladder wall)
Spinal XR: vertebral anomaly
MRI: confirm or exclude a non-bony spinal defect such as tethering of the cord
How would you treat daytime enuresis?
Treat any causes. Other children may benefit from star charts, bladder training and pelvic floor exercises
What is secondary enuresis?
The loss of previously achieved urinary continence
What may cause secondary enuresis?
Emotional upset (common)
UTI
Polyuria from an osmotic diuresis in DM or a renal concentrating disorder (sickle cell or chronic renal failure)
When might transient proteinuria be physiological?
During febrile illnesses or after exercise
How should persistent proteinuria be quantified?
By measuring the urine protein/creatinine ratio in an early morning sample.
What are the causes of proteinuria?
Commonest: orthostatic (postural) proteinuria
Others:
Glomerular abnormalities - minimal change disease, glomerulonephritis, abnormal glomerular basement membranes
Increased glomerular filtration pressure
Reduced renal mass
HTN
Tubular proteinuria
What is nephrotic syndrome?
Heavy proteinuria results in a low plasma albumin and oedema.
What are the causes of nephrotic syndrome?
The cause is unknown but a few cases are secondary to HSP and other vasculitides (SLE or malaria)
What are the clinical signs of nephrotic syndrome?
Periorbital oedema (particularly on waking, the earliest sign)
Scrotal or vulval, leg and ankle oedema
Ascites
Breathlessness due to pleural effusions and abdominal distention
What investigations are performed at presentation of nephrotic syndrome?
Urine protein (dipstick)
FBC and ESR, U&E, creatinine, albumin
Complement levels - C3, C4
Antistreptolysin O and anti-DNAase B titres and throat swab
Urine microscopy and culture
Urinary sodium concentration
Hep B and C and possible malaria screen
What are the features suggesting the nephrotic syndrome is steroid sensitive?
Age between 1-10 years No macroscopic haematuria Normal BP Normal complement levels Normal renal function
How would you treat nephrotic syndrome?
Oral corticosteroids (prednisolone) that is gradually tapered. If no response, renal biopsy is required.
What severe complications are children with nephrotic syndrome susceptible to?
Hypovolaemia
Thrombosis
Infection
Hypercholesterolaemia
What are the clinical features of hypovolaemia secondary to nephrotic syndrome?
Abdominal pain and feeling faint. There is peripheral vasoconstriction and urinary sodium retention.
What are the investigation results in hypovolaemia secondary to nephrotic syndrome?
A low urinary sodium and a high packed cell volume of RBC
How would you treat hypovolaemia secondary to nephrotic syndrome?
IV albumin.
Assess clinically peripheral oedema and daily weight
How would nephrotic syndrome causes thrombosis?
A hypercoagulable state, due to urinary losses of antithrombin, thrombocytosis which may be exacerbated by steroid therapy, increased synthesis of clotting factors and increased blood viscosity from the raised haematocrit , predisposes to thrombosis
What is the prognosis of steroid-sensitive nephrotic syndrome?
1/3 resolve directly
1/3 infrequent relapses
1/3 frequent relapses - steroid dependent
What haematuria suggests glomerular haematuria?
Brown urine, the presence of deformed red cells (which occurs as they pass through the basement membrane) and casts, and is often associate with proteinuria
What is the most common cause of haematuria?
UTI
When would a renal biopsy be indicated in haematuria?
There is significant persistent proteinuria
There is recurrent macroscopic haematuria
Renal function is abnormal
The complement levels are persistently abnormal
What are the causes of haematuria?
Non-glomerular - infection, trauma, stones, tumours, sickle cell disease, bleeding disorders, renal vein thrombosis, hypercalciuria
Glomerular - acute glomerulonephritis, chronic glomerulonephritis, IgA nephropathy, familial nephritis, thin basement membrane disease
What investigations of haematuria should all patients have?
Urine microscopy and culture
Phosphate ad calcium excretion
Kidney and urinary tract US
Plasma urea, electrolytes, creatinine, calcium, phosphate, albumin
FBC, platelets, clotting screen, sickle cell screen
What investigations should be performed if there is haematuria suggestive of glomerular haematuria?
ESR, complement levels and anti-DNA antibodies
Throat swab and antistreptolysin O/anti-DNAse B titres
Hep B and C screen
Renal biopsy if indicted
What are the causes of acute nephritis?
Post-infectious (including strep)
Vasculitis (HSP, or rarely SLE, Wegener granulomatosis, microscopic arteritis and polyarteritis nodosa
IgA nephropathy and mesangiocapillary glomerulonephritis
How does acute nephritis affect the kidney?
Increased glomerular cellularity restricts glomerular blood flow and therefore filtration is decreased.
What are the clinical features of acute nephritis?
Decreased urine output and volume overload
HTN, which may cause seizures
Oedema, characteristically around he eyes
Haematuria and proteinuria
How would you manage acute nephritis?
Attention to both water and electrolyte balance and the use of diuretics when necessary
What are the clinical features of HSP?
Characteristic skin rash Arthralgia Periarticular oedema Abdominal pain Glomerulonephritis
What age and sex is HSP most common?
Between 3 and 10 years, more common in boys
When (season) is HSP most common?
It peaks during the winter.
What is the pathophysiology of HSP?
Genetic predisposition and antigen exposure increased circulating IgA and disrupt IgG. IgA and IgG interact to produce complexes that activate complement and are deposited in affected organs, precipitating an inflammatory response with vasculitis
Where does the rash in HSP present?
It is symmetrically distributed over the buttocks, the extensor surfaces of the arms and legs, and the ankles. The trunk is spared unless lesions are induced by trauma
What are the feature of the rash in HSP?
The rash may be initially urticarial, rapidly becoming maculopapular and purpuric, is characteristically palpable and may recur over several weeks.
Which joints are especially effects by HSP?
Knees and ankles
What are the abdominal complications that may occur with HSP?
Haematemesis and melaena, intussusception may occur
What are some risk factors for progressive renal disease with HSP?
Heavy proteinuria, oedema, HTN and deteriorating renal function
Does HSP need follow up?
All children who have renal involvement need follow up for a year to detect those with persisting urinary abnormalities
How does IgA nephropathy present?
Episodes of macroscopic haematuria, commonly is associated with URTI
What is Alport syndrome?
The commonest familial nephropathy. It is usually an X-linked disorder that progresses to end-stage renal failure by early adult life in males and is associated with nerve deafness and ocular defects
What are some characteristic symptoms of haematuria due to vasculitis?
Fever, malaise, weight loss, skin rash and arthropathy with prominent involvement of the respiratory tract in Wegener disease.
How does you diagnose haematuria due to vasculitis?
ANCA (antineutrophil cytoplasm antibodies) are present and diagnostic.
How do you treat haematuria due to vasculitis?
Steroids, plasma exchange and IV cyclophosphamide, which may need to be continued for months.
What are the causes of HTN in children?
Renal - renal parenchymal disease, renovascular (renal vein thrombosis), PCKD, renal tumours
Coarctation of the aorta
Catecholamine excess - phaeochromocytoma, neuroblastoma
Endocrine - congenital adrenal hyperplasia, Cushing syndrome, hyperthyroidism
How does HTN in children present?
Vomiting, headaches, facial palsy, hypertensive retinopathy, convulsions or proteinuria. Failure to thrive is common in infants.
What are the causes of a unilateral palpable kidney?
Multicystic kidney Compensatory hypertrophy Obstructed hydronephrosis Renal tumour (Wilms tumour) Renal vein thrombosis
What are the causes of bilateral palpable kidneys?
PCKD (both recessive and dominant)
Tuberous sclerosis
Renal vein thrombosis
What are some predisposing causes of renal calculi (stones)?
UTI
Structural abnormalities of the urinary tract
Metabolic abnormalities
Are phosphate or calcium stones more common and what are they associated with?
Phosphate stones are most common, and associated with infection, especially with Proteus
What are the causes of calcium-containing stones?
Deposition of calcium in the parenchyma may occur with hypercalciuria, hyperoxaluria and distal renal tubular acidosis
How would renal calculi present?
May be with haematuria, loin or abdominal pain, UTI or passage of a stone
How would you manage renal calculi?
Stones that are not passed spontaneously should be removed, either by lithotripsy or surgery. A high fluid intake is recommended.
What are the causes of generalised proximal tubular dysfunction (Fanconi syndrome)?
Idiopathic
Secondary to inborn errors of metabolism - glycogen storage disorders, galactosaemia, fructose intolerance, Wilson disease
Acquired - heavy metals, drugs and toxins, vitamin D deficiency
What are the presenting features of Fanconi syndrome?
Polydypsia and polyuria Salt depletion and dehydration Hyperchloraemic metabolic acidosis Rickets Failure to thrive/poor growth
How can you classify acute kidney injury?
Prerenal - most common in children
Renal - salt and water retention; blood, protein and casts are often present in the urine
Postrenal - urinary obstruction
What are the prerenal causes of AKI?
Hypovolaemia - gastroenteritis, burns, sepsis, haemorrhage, nephrotic syndrome
Circulatory failure
What are the renal causes of AKI?
Vascular - haemolytic uraemia syndrome, vasculitis, embolus, renal vein thrombosis
Tubular - acute tubular necrosis, ischaemic, toxic, obstructive
Glomerular - glomerulonephritis
Interstitial - interstitial nephritis, pyelonephritis
What are the post-renal causes of AKI?
Obstruction - congenital (posterior urethral valves), acquired (blocked urinary catheter)
How would you investigate AKI?
Monitor circulation and fluid balance.
US may identify cause
How would you treat prerenal failure cause of AKI?
Hypovolaemia is most likely cause, so treat with fluid replacement and circulatory support if needed
How would you treat renal failure cause of AKI?
Circulatory overload so restrict fluid intake and challenge with a diuretic. A high-calorie, normal protein feed will decreased catabolism, uraemia and hyperkalaemia
How would you treat post renal failure of AKI?
Surgery can performed once fluid volume and electrolyte abnormalities have been corrected
When is dialysis in AKI indicated?
Failure of conservative management Hyperkalaemia Severe hypo- or hypernatraemia Pulmonary oedema or HTN Severe acidosis Multisystem failure
How would you treat metabolic acidosis?
Sodium bicarbonate
How would you treat hyperphosphataemia?
Calcium carbonate
Dietary restriction
How would you treat hyperkalaemia?
Calcium glutinate if ECG changes Salbutamol Calcium exchange resin Glucose and insulin Dietary restriction Dialysis
What is haemolytic uraemic syndrome?
A triad of acute renal failure, microangiopathic haemolytic anaemia and thrombocytopaenia. Typically, it is secondary to GI infection. It usually follows a prodrome of bloody diarrhoea
How would you treat haemolytic uraemic syndrome?
Early supportive therapy, including dialysis. Follow up is necessary as there may be persistent proteinuria and the development of HTN and declining renal function in subsequent years
What are some causes of chronic renal failure in children?
Structural malformation Glomerulonephritis Hereditary nephropathies Systemic diseases Miscellaneous/unknown
What are the clinical features of CKD in children?
Anorexia and lethargy Polydipsia and polyuria Failure to thrive/growth failure Bony deformities from renal osteodystrophy HTN Acute-on-chronic renal failure Incidental findings of proteinuria Unexplained normochromic, normocytic anaemia
How would you manage CKD?
Prevent the symptoms and metabolic abnormalities of CKD, to allow normal growth and development and to preserve residual renal function. Diet and GI feeding, phosphate restriction and activated vitamin D, salt supplements and free access to water, bicarbonate supplements, erythropoietin, growth hormone and dialysis and transplantation
How does diet need to change in children with CKD?
Anorexia and vomiting are common so calorie supplements and NG feeding is often necessary. Protein intake should be sufficient to maintain growth and a normal albumin, whilst preventing the accumulation of toxic metabolic byproducts
What hormonal abnormalities are linked with CKD?
Growth hormone resistance with high growth hormone levels but poor growth.
