Urinary Tract Infection (UTI) Overview

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Questions and Answers

What is the prevalence of urinary tract infections (UTIs) in girls and boys during early childhood?

UTIs occur in 1-3% of girls and 1% of boys.

Which bacteria are responsible for the majority of urinary tract infections in girls?

75-90% of UTIs in girls are caused by Escherichia coli.

What are the common clinical manifestations of pyelonephritis in infants?

Common manifestations include abdominal or flank pain, fever, malaise, and nausea.

What differentiates cystitis from pyelonephritis?

Cystitis typically does not cause fever and does not result in renal injury. Signup and view all the answers

What is asymptomatic bacteriuria and how does it manifest?

Asymptomatic bacteriuria is a positive urine culture without symptoms of infection. Signup and view all the answers

Why are uncircumcised boys at higher risk for UTIs during the first year of life?

Uncircumcised boys have higher risks due to bacterial flora beneath the prepuce. Signup and view all the answers

What are the three basic forms of urinary tract infections?

The three basic forms are pyelonephritis, cystitis, and asymptomatic bacteriuria. Signup and view all the answers

What symptoms are typically associated with cystitis?

Symptoms of cystitis include dysuria, urgency, frequency, and suprapubic pain. Signup and view all the answers

How does the male to female ratio of UTIs change with age?

In infants, the ratio is approximately 2.8-5.4:1, shifting to 1:10 by 1-2 years. Signup and view all the answers

What is the primary route of infection for urinary tract infections?

All UTIs are ascending infections from the fecal flora infecting the bladder via the urethra. Signup and view all the answers

What are the two most significant consequences of chronic renal damage caused by pyelonephritis?

Arterial hypertension and chronic renal insufficiency. Signup and view all the answers

What initial treatment is suggested for acute cystitis to prevent its progression to pyelonephritis?

Prompt treatment with appropriate antibiotics is suggested. Signup and view all the answers

What conditions warrant the immediate collection of a specimen of bladder urine for culture in UTI cases?

Severe symptoms or uncertainty in the diagnosis. Signup and view all the answers

What is the recommended regimen for trimethoprim-sulfamethoxazole in treating UTIs if started before culture results?

A 3-5 days course at a dosage of 10 mg/kg trimethoprim and 40 mg/kg sulfamethoxazole per 24 hours. Signup and view all the answers

Why is nitrofurantoin considered advantageous in treating certain UTIs?

It is effective against Klebsiella and Enterobacter organisms. Signup and view all the answers

How should treatment change in cases of acute febrile infection suggesting pyelonephritis?

A 10-14 days course of broad-spectrum antibiotics is preferable. Signup and view all the answers

What urine colony count indicates the need for a repeated culture if results are uncertain?

A colony count between $10^4$ and $10^5$ colonies of Gram-negative organisms. Signup and view all the answers

In treating UTIs, which antibiotic has no clear advantage over sulfonamide or nitrofurantoin?

Amoxicillin. Signup and view all the answers

What are the four conditions under which children may require urgent intervention for UTIs?

Dehydration, vomiting, inability to drink fluids, and severe symptoms. Signup and view all the answers

What is the therapeutic dose range for nitrofurantoin in treating UTIs in children?

5-7 mg/kg per day in 3-4 divided doses. Signup and view all the answers

Why are blood cultures recommended in cases of pyelonephritis, especially in infants?

Blood cultures are recommended because sepsis is common in pyelonephritis, particularly in infants. Signup and view all the answers

What are the primary purposes of obtaining a renal sonogram in children with clinical pyelonephritis?

A renal sonogram is used to demonstrate an enlarged kidney, rule out hydronephrosis, and detect structural abnormalities. Signup and view all the answers

What does a significant difference in renal length suggest in a child with acute pyelonephritis?

A significant difference in renal length may indicate renal growth impairment. Signup and view all the answers

What is the significance of performing a DMSA scan in patients with febrile UTIs?

A DMSA scan displays parenchymal involvement and is useful for assessing renal scarring, particularly in cases of vesicoureteral reflux. Signup and view all the answers

List two host risk factors that can increase the likelihood of developing UTIs in children.

Two host risk factors include vesicoureteral reflux and obstructive uropathy. Signup and view all the answers

Why might excretory urography be considered less sensitive than DMSA scans for detecting renal scarring?

Excretory urography is less sensitive than DMSA scans for renal scarring due to suboptimal visualization and a slight risk of contrast allergy. Signup and view all the answers

How can voiding dysfunction in toilet-trained children contribute to UTIs?

Voiding dysfunction can lead to infrequent urination and incomplete bladder emptying, increasing the likelihood of bacteriuria. Signup and view all the answers

In what way does constipation increase the risk of UTIs in children?

Constipation can cause voiding dysfunction, leading to incomplete bladder emptying and increased UTI risk. Signup and view all the answers

What distinguishes the incidence of UTIs in breastfed babies from those fed formula?

The incidence of UTIs is lower in breastfed babies compared to those fed formula. Signup and view all the answers

Why might renal scanning be important after a child experiences pyelonephritis?

Renal scanning is important to detect nephronia, local pyelonephritis, and assess kidney damage from the infection. Signup and view all the answers

What can cause vesico-ureteral reflux, and how does it lead to acute pyelonephritis?

Vesico-ureteral reflux can be caused congenitally or acquired due to cystitis and dysfunction of the detrusor muscle, leading to bacteria reaching the kidney and causing acute pyelonephritis. Signup and view all the answers

What are the criteria used to diagnose a UTI in a toilet-trained child?

For a UTI diagnosis in a toilet-trained child, a culture must show greater than 100,000 colonies of a single pathogen, or 10,000 colonies if the child exhibits symptoms. Signup and view all the answers

What steps should be taken for urine collection in uncircumcised males?

In uncircumcised males, the prepuce must be retracted before collecting a urine specimen to prevent contamination. Signup and view all the answers

What indicates a possible UTI in infants using a catheterized sample?

A catheterized sample indicating a UTI shows more than 50,000 colonies of a single pathogen or 10,000 colonies if the infant is symptomatic. Signup and view all the answers

How is pyuria related to urinary tract infection diagnosis?

Pyuria, the presence of leukocytes in the urine, suggests infection, though infection can occur without it, making it confirmatory rather than diagnostic. Signup and view all the answers

What laboratory findings might indicate renal involvement in urinary tract infections?

White blood cell casts in urinary sediment suggest renal involvement during urinary tract infections. Signup and view all the answers

What general inflammatory markers may increase in cases of acute renal infection like pyelonephritis?

In acute renal infections, leukocytosis, neutrophilia, increased ESR, and C-reactive protein may all increase as nonspecific markers of inflammation. Signup and view all the answers

What are the implications of finding microscopic hematuria in acute cystitis?

Microscopic hematuria is common in acute cystitis, indicating potential bladder inflammation or irritation. Signup and view all the answers

In the case of renal abscess, what white blood cell counts are commonly observed?

In a renal abscess, white blood cell counts can commonly increase to between 20,000 and 25,000/mm³. Signup and view all the answers

Why is it important to obtain urinalysis from the same specimen that is cultured?

It is important to obtain urinalysis from the same specimen as the cultured sample to ensure accurate correlation between symptoms and infection diagnosis. Signup and view all the answers

Study Notes

Urinary Tract Infection (UTI) Prevalence

UTIs occur in 1-3% of girls and 1% of boys.
In girls, the first UTI typically occurs by age 5, peaking during infancy and toilet training.
In boys, most UTIs occur during the first year of life.
UTIs are significantly more common in uncircumcised boys, particularly during the first year.
The male-to-female ratio for UTIs during the first year is 2.8-5.4:1.
After 1-2 years, females are more prone to UTIs, with a 1:10 ratio.

UTI Etiology

Colonic bacteria cause 75-90% of UTIs in girls.
Escherichia coli is the most common culprit, followed by Klebsiella spp. and Proteus spp.
In boys over 1 year old, Proteus spp is as common as E. coli.
Other pathogens include gram-positive organisms like Staph saprophyticus, enterococcus and adenovirus (cystitis).
These pathogens affect both sexes.

UTI Clinical Manifestations

Pyelonephritis
Cystitis
Asymptomatic bacteriuria (ABU)
Focal nephronia
Renal and perirenal abscess

Clinical Pyelonephritis

Symptoms may include abdominal/flank pain.
Often accompanied by fever and malaise.
Nausea, vomiting, and diarrhea are possible.
Infants may show nonspecific symptoms like poor feeding, jaundice, irritability and weight loss.
Fever without a focus of infection is common in infants under 24 months, with pyelonephritis being the most common serious bacterial infection.
Acute pyelonephritis can lead to renal injury and scarring.

Cystitis

Symptoms suggest bladder involvement.
Include dysuria, incontinence, malodorous urine, urgency, frequency and suprapubic pain.
Cystitis does not cause fever or renal injury.
Malodorous urine is not specific for a UTI.

Asymptomatic Bacteriuria (ABU)

A positive urine culture without any visible signs or symptoms of infection.
More prevalent in girls, especially in pre-school or school-aged children (1-2% in girls and 0.03% in boys).
Incidence decreases with age.
Benign condition, and not associated with renal injury.

UTI Pathogenesis and Pathology

UTIs are ascending infections; bacteria originate from fecal flora, colonize the perineum, and ascend to the bladder through the urethra.
In uncircumcised boys, bacteria originating from beneath the foreskin (prepuce) are a common source.
Vesico-ureteral reflux (VUR) is a common cause of UTIs, particularly in children with congenital or acquired reflux.
Urine can backflow from the bladder to the kidney in VUR; this introduces bacterial pathogens to the kidney, potentially leading to pyelonephritis.
Kidney infections can rarely develop from blood-borne bacteria.
Certain papillary structures in the kidneys allow urine to flow into the collecting tubes; if infected, this can result in an inflammatory/immunologic response that leads to damage and scarring of the kidneys.

UTI Diagnosis

Suspicion of UTI based on symptoms or urinalysis results.
Urine culture is essential for confirming a UTI.
For toilet-trained children, a mid-stream urine sample is collected.
Urine sample culture should show >100,000 colonies of a single pathogen or >10,000 colonies and symptoms for UTI diagnosis.
Uncircumcised males require prepuce retraction.
Infants require sterile collection bags after skin disinfection.
Positive urinalysis results coupled with symptoms and >100,000 colonies in culture suggest a UTI.
If criteria aren't met, cultures from suprapubic or catheterized samples may be used to confirm or rule out a UTI.

UTI Urinalysis

Pyuria (leukocytes in urine) indicates possible infection.
An absence of pyuria doesn't exclude the presence of urine infection.
White blood cells in the urine (hematuria) or casts often accompany acute cystitis.
White blood cell casts in the urinary sediment suggest kidney involvement.
If a child with symptoms has negative urinalysis, a UTI could still be present.
Lab tests like leukocytosis, neutrophilia, increased ESR, and C-reactive protein (nonspecific inflammatory markers) are possible findings in acute kidney infection (pyelonephritis), elevated to 20-25,000/mm³ in cases of renal abscess.
Blood cultures are often done to rule out sepsis in pyelonephritis, particularly in infants or children with urinary tract abnormalities.

Imaging Studies

Renal sonogram is common for clinical pyelonephritis (febrile UTI) to assess kidney size, rule out renal scarring, hydronephrosis, and structural problems.
Large disparity in kidney size may signify growth impairment.
DMSA scans assess parenchymal involvement; used to evaluate for kidney scarring in febrile UTIs.
Vesicoureteral reflux (VUR) is assessed using a voiding cystourethrogram (VCUG) in cases of recurrent febrile UTIs or atypical symptoms, such as failure to respond to antibiotics, abnormal ultrasound results (hydronephrosis, enlarged bladder wall thickness), severe lower UTI symptoms with multiple episodes.

Host Risk Factors

Vesicoureteral reflux (VUR).
Obstructive uropathy leading to urinary stasis.
Urethral instrumentation during procedures.
Toilet training difficulties or refusal to use the bathroom.
Voiding dysfunction, especially in young girls.
Neurogenic bladder.

UTI Complications

Pyelonephritis: an acute kidney infection.
Renal scarring and/or damage.
Chronic kidney disease/insufficiency
Sepsis (blood poisoning).

UTI Treatment

Acute cystitis and pyelonephritis should be treated promptly.
Mild or uncertain cases might delay confirmation with a urine culture.
Initial treatment often includes antibiotics, such as trimethoprim-sulfamethoxazole or nitrofurantoin.
If the infection is severe or in infants or small children, IV antibiotics are necessary. Also important to observe for worsening symptoms, or if symptoms worsen, immediate evaluation of severe infection in children.
Alternative or additional options include broad-spectrum antibiotics (oral 3rd generation cephalosporins).
A urine culture performed 1-2 weeks following treatment ensures sterility.

UTI Treatment for Children Requiring Hospitalization

Dehydration, vomiting or inability to drink fluids, less than 1 month of age, or if sepis is suspected, hospitalization is indicated.
Intravenous fluids and antibiotics.

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Description

This quiz explores the prevalence, etiology, and clinical manifestations of urinary tract infections (UTIs) in children. Understanding these components is essential for identifying and managing UTIs effectively in both genders. Test your knowledge on the statistics and pathogens associated with UTIs.