27) Urinary tract infections. Urolithiasis. Flashcards
age of onset for UTI ?
bimodal - one peak in the first year of life and another peak at between 2 and 4 years of age which corresponds to the age of toilet training
what are the pathogens which causes UTI?
Escherichia coli accounts for 80 to 90% - gram negative bacilli
followed by proteus mirabilis,
pseudomonas aeriginosa
Other organisms include Enterobacter aerogenes, Klebsiella pneumoniae, , Citrobacter,, Enterococcus spp., and Serratia spp
what is the pathogenesis of UTI in children?
UTI 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
Incomplete bladder emptying - Obstruction by a loaded rectum from constipation
Infrequent voiding
Vulvitis
neurogenic bladder
structural anomality
vesicoureteric reflux and obstruction
catheterization
increased susceptibility of girls to UTI might be explained by the relatively shorter length of the female urethra and the regular heavy colonization of the perineum by enteric organisms
actors that increase colonization of the female perineum include high vaginal pH, douching
clinical manifestation of UTI ?
neonatal period, : nonspecific fluctuating temp lethargy, irritability apnea, febrile convulsion >6mo or metabolic acidosis poor sucking, vomiting, DIARRHEA suboptimal weight gain Foul-smelling urine is an uncommon, but more specific symptom of UTI
remain nonspecific throughout infancy
Unexplained fever - esp over 39 degrees (WITHOUT RIGOR)
discomfort with urination
ABDOMINAL PAIN or loin pain
After the second year of life : more specific
pyelonephritis : fever, chills, rigor
vomiting,
flank pain,
back pain, and costovertebral angle tenderness
Since fever is usually absent in lower UTIs, the presence of fever and flank pain should be taken as a sign of more serious infection, e.g., pyelonephritis.
Lower tract symptoms and signs : suprapubic pain and tenderness Hematuria dysuria, urinary frequency, urgency, cloudy urine, malodorous urine, daytime wetting,
cystitis, when fever is absent or low grade
dysuria alone is usually due to cystitis
diagnosis of UTI?
chilld with nappies - absorbent pads with naps
urinalysis and urine culture - GOLDENS STANDARD
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how to collect urine samples
attaching a sterile bag to the perineum
A clean-catch midstream urine specimen obtained after proper cleansing of the external genitalia is satisfactory in children who can void on demand
Suprapubic aspiration is a useful method to obtain a clean urine sample from infants
method of choice in the severely ill infant under 1 year old
catheterization is for specific situations such as a febrile child in poor general health or appears severely ill
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Microscopy should be performed to detect bacteriuria and pyuria
(Urinary white cells are not a reliable features of UTI, as they may lyse during storage and may be present in febrile children without a UTI and in children with balanitis and vulvovaginitis)
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growth o mixed organisms in culture - represent usually contamination
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dipstick
leukocyte esterase dipstick test demonstrates the presence of pyuria
nitrite test (non-nitrate-reducing bacteria, Pseudomonas spp., Enterococcus spp., Staphylococcus saprophyticus)
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us
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DMSA can be used to detect acute pyelonephritis and renal scarring . Decreased renal uptake of the isotope suggests acute pyelonephritis or renal scarring
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if urtheral obstruction suspected - MCUG
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the diagnosis of UTI in children 2 to 24 months requires positive dipstick test (leukocyte esterase and/or nitrite test), microscopy positive for pyuria or bacteriuria, and the presence of ≥ 50,000cfu/ml of a uropathogen in a catheterized or suprapubic aspiration specimen / positive urine culture of a single uropathogen ≥ 100,000cfu/ml in a midstream urine specimen
In toilet-trained children, a clean-catch midstream urine specimen rather than a catheterized or a suprapubic aspiration
what is the treatmnet of UTI ?
Children should be instructed to void about every 1.5 to 2hr and never to hold the urine to the last minute
Meticulous genital hygiene and adequate fluid intake should be encouraged
The empiric antibiotic chosen should provide adequate coverage for Gram-negative rods notably E. coli and Gram-positive Cocci (enterococci)
orally or parenterally is equally efficacious
Parenteral antibiotic therapy is recommended for infants ≤ 2 months
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outpatient and oral suspension therapy -
amoxicillin clavulanate
>3 months
25-50mg/kg/day q12h
adolescents
(>10 or more )
250-500mg bid
cefixime
12/mg.kg/day q12 for 1 day
then 8mg/kg.day q12h thereafter
TMP- SMX / co - trimoxazole
>2months 8-10mg/kg.day bid
adolescents - 160mg bid
3-7 days
oral cephalosporins may be appropriate - but ineffectiveness for an enterococcal infection.
Empiric use of amoxicillin and trimethoprim/sulfamethoxazole (TMP-SMX) has limited use due to potential resistance of E coli
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combination IV ampicillin 100-200mg/kg/day q6h and intravenous/ intramuscular gentamycin 5 mg -7.5mg/kg/day q8h
or
ampicillin in combination with a third-generation cephalosporin, such as
IV cefotaxime 100 to 150mg/kg/day q8 eight hours intravenously,
IV ceftriaxone 50- 75mg/kg/day q12h
total of 10-14 days
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cephalosporins less nephrotoxic than gentamycin
Ampicillin is important to cover Enterococcus
Antibiotic resistance to nitrofurantoin is low . However, the inability to achieve high tissue levels limits its use in infants and young children with febrile UTI
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after 48–72 hours of antibiotic therapy suggest possible complicated cystitis
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what is the treatment more than 3 months wit upper UTI or acute pyelonephritis ?
oral suspension - 10 days
cephalosporin ,
trimethoprim or co amoxiclav
or
> 1 yr
ciprofloxacin
what are the complications of UTI ?
pyelonephritis
renal abcess
especially if the UTI is recurrent or causes permanent renal damage and scar!!!!
: important cause of renal scarring is renal hypodysplasia which is often congenital
or urinary tract anomalies such as high-grade vesicoureteric reflux or urinary tract obstruction
renal scar develop after first symptomatic episode of pyelonephritis
10% of children with a renal scar will develop hypertension in adolescence
renal scar - hypertension and chronic renal failure
Bacteremia :prematurity, young age (< 1 year), and high serum creatinine
renal insufficiency : due to pyelonephritis
use of nephrotoxic antibiotics
prevention of UTI with severe vesicoureteric reflux or frequent recurrence?
used in under 2 years of age
Continuous prophylaxis with either low-dose nitrofurantoin (1 to 2mg/kg)
or TMP-SMX (1 to 2mg of TMP and 5 to 10mg of SMX/kg) once a day orally is effective
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generally
high fluid intake
regular voiding
double micturition - to empty bladder
prevention and treatmnet of constipation
lactobacillus acidophilus - politic to encourage colonisation of the gut
what causes renal stones in paediatrics ?
recurrent UTI
neurogenic bladder,
bladder surgeries,
obstructive anomalies
low salt
potassium supplements - reduce urinary calcium
bicarb supplements - increase urinary citrate
genitourinary anomalies duplex ureter, posterior uretheral valves,
bladder exstrophy are found in approximately 30% of children with urolithiasis
metabolic abnormalities include:
1) hypercalcemic hypercalciuria - Hyperparathyroidism Hypervitaminosis D adrenal insufficiency sarcoidosis malignant neoplasma
2) hypocalcemic hypercalciuria
hypoparathyroidism
autosomal dominant hypocalcemic hypercalciuria
3) Normocalcemia hypercalciurea:
idiopathic hypercalciuria!
Furosemide
Topiramate - anticonvulsant
Ketogenic diet
genetic :
dent disease - X-linked inherited condition (characterized by low-molecular-weight proteinuria, nephrocalcinosis, hypercalciuria, nephrolithiasis, and chronic kidney disease, defect is in proximal tubular function, and occasionally glucosuria, aminoaciduria, metabolic acidosis, and hypophosphatemia)
Bartter syndrome
autosomal recessive condition characterized by renal salt wasting, hypokalemia, metabolic alkalosis, hypercalciuria, and normal serum magnesium levels. Children younger than 6 years typically present with salt craving, polyuria, dehydration, emesis, constipation, and failure to thrive.
Severe polyhydramnios, prematurity, and occasionally sensorineural deafness are the hallmark featureautosomal
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis
- AR
childhood with seizures or tetany caused by hypomagnesemia. Other clinical manifestations include frequent urinary tract infections (UTI), polyuria, polydipsia, failure to thrive
Primary distal renal tubular acidosis (dRTA)
systemic acidosis as a result of the inability of the distal tubule to adequately acidify the urine. Failure to thrive, polyuria, polydipsia, hypercalciuria, hypocitraturia, nephrocalcinosis, renal calculi, and hypokalemia are common presenting signs in infancy
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hypocitraturia,
hyperoxaluria
Cystinuria
autosomal recessive disorder
may present as early as infancy with staghorn calculi
poor solubility of cystine in the urine causes precipitation in the collecting system, which, if left untreated, usually results in recurrent episodes of calculi and long-term risk for renal failure
Hyperuricosuria - inherited disorders of purine metabolism , lymphoproliferative disorders, and polycythemia
chemo
familial juvenile hyperurecemic nephropathy
excessive purine intake (animal protein, anchovies, and mussels),
hemolysis,
uricosuric medications (probenecid, salicylates, and losartan)
what are the classification of renal stones and characteristics ?
Calcium oxalate and calcium phosphate stones (~70%):
Magnesium-ammonium-phosphate stones (~15%) :
due to infection of urinary tract with bacteria→urine into ammonium, which
makes it more alkaline → this causes precipitation of magnesium, ammonium and phosphate
Uric acid stones:
◦ X-ray negative
Cysteine stones
what is the clinical presentation of renal stones in pediatrics ?
adult presentation of acute, severe flank pain, which radiates to the groin is uncommon in children, particularly in children younger than 5 years.
pain localized to the abdomen, flank, or pelvis
Macroscopic or microscopic hematuria
dysuria
urinary frequency
in younger children these classic symptoms may not be present, instead: Fussiness and
vomiting may be the only symptoms
anemia
diagnosis of renal stones ?
us
sensitivity for detecting ureteral calculi and smaller calculi (<5 mm) is poor
Noncontrast computed tomography remains the gold standard and is indicated in children with persistent symptoms of urolithiasis and a nondiagnostic US
intravenous pyelogram can be considered
DMSA - inorder to know extend of renal involvement
A 24-hour urine collection should be analyzed for calcium, oxalate, uric acid, sodium, citrate, creatinine levels, volume, pH, and cystine
serum creatinine level is essential to evaluate for possible acute kidney injury or chronic kidney disease.
Serum calcium, phosphorous, bicarbonate, magnesium, and uric acid levels are effective, pth
what is the management of renal stones in pediatrics ?
Pain associated with the passage of a stone is often severe
give promptly narcotic analgesics (morphine sulfate) and/or nonsteroidal antiinflammatory drugs (Ketorolac).
If the patient is vomiting or unable to drink, parenteral hydration should be used to maintain a high urine flow rate
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promote the passage of stones and reduce symptoms (medical expulsive therapy), such as alpha-adrenergic blockers (tamsulosin) and calcium-channel blockers (nifedipine
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Percutaneous nephrostomy may be needed as a temporary measure if there is obstruction to urine flow
completely obstructs the bladder outlet -Foley catheterisation.
urine outflow established, the approach for removal vesicostomy versus cystoscopy versus lithotripsy is usually determined by the pediatric urologist
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Extracorporeal shock wave lithotripsy
preferred for small stones less than 10 mm in size.
this is not good for cystien stones - which are hard
Percutaneous nephrolithotomy is the standard therapy used for large kidney stones greater than 20 millimeters or stones in the lower kidney
ureteroscopic stone extraction - for ureteric stones
open surgery - esp for urteropelvic junction obstruction
how do you prevent future renal stones from forming ?
increase their fluid intake
calcium - paradox of higher calcium intake can actually reduce the calcium stones in recent studies
reduce animal protein
oxalate
reduce oxalate and vit c
diuretics - thiazide diuretic is often required for children with hypercalciuria who do not respond to a restricted sodium diet. hydrochlorothiazide 1 to 2 mg/kg/d
Amiloride can be added for its potassium-sparing effect
alkali agents - treatment with potassium citrate
reduce the recurrence of calcium oxalate stone
Thiol-containing agents
exclusively for patients with cystinuria in which fluid, dietary modifications urinary alkalinization are ineffective in preventing stone recurrences or dissolving preexisting stones. d-penicillamine
Allopurinol
for most children with uric acid calculi Allopurinol 4–10 mg/kg/d
