Regarding urinalysis in patients with dysuriafrequency syndrome, which ONE of the following statements is TRUE?
Answer: B: A positive u-dipstix for nitrites is caused by bacteria that convert nitrates to nitrite, usually coliform bacteria like E.coli, Enterococcus, Pseudomonas species and Acinetobacter (usually responsible for complicated UTIs) do not convert nitrates and therefore 204 CHAPTER 7 Renal Emergencies usually yield a negative nitrate test. Although nitrate reaction by dipstix has a very high specificity (90%) and a positive result is useful in confirming diagnosis of UTI, it has a low sensitivity (about 50%) so it is not always useful as a screening exam because a negative test does not exclude the diagnosis of UTI.
Visual inspection and assessment of the odour of urine is generally not helpful in determining infection. Cloudiness in fresh urine is usually not due to white blood cells or bacteria, but rather due to large amounts of protein or amorphous phosphate crystals. Malodour of urine may be caused by diet or medications and is not a reliable sign if infection.
The absence of pyuria and bacteriuria in a patient with clinical suspicion of UTI mandates the exclusion for an obstructed, infected kidney and an ultrasound and/or CT is therefore indicated. In males <50 years of age, the symptoms of dysuria or urinary frequency are usually due to sexually transmitted disease-related infection of the urethra or prostate. Withholding urination may enhance the likelihood of a positive result on urethral swab testing in a male patient with minimal discharge. Obtaining a first void specimen rather than midstream stream specimen is helpful to diagnose urethritis.
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Which ONE of the following statements is TRUE regarding asymptomatic bacteriuria?
Answer: D: Asymptomatic bacteriuria is diagnosed in the presence of >105 CFU/mL of a single bacterial species, ideally on two successive urine cultures, in patients without symptoms. It is uncommon (5%) in healthy, non-pregnant, sexually active women aged 18–40 years but occurs in up to 30% of pregnant women and up to 40% of female nursing home residents. It is also common in patients with indwelling urinary catheters.
Screening and treatment is only indicated in pregnant women and patients before urological procedures. Complications that may result from untreated bacteriuria in pregnancy include premature labour, perinatal mortality, maternal anaemia and maternal pyelonephritis. In all other cases, antibiotic treatment does not decrease symptomatic episodes but will lead to the emergence of more resistant organisms.
Regarding a UTI diagnosis, which ONE of the following statements is TRUE?
Answer: B: The presence of gross haematuria in patients with a UTI (hemorrhagic cystitis) occurs in 30–40% of female cases, most often young adults. It is unusual in males and a more serious cause must be considered. Gross haematuria is more common with lower UTI (haemorrhagic cystitis) and occurs infrequently with pyelonephritis. When present, the differential should include calculi, cancer, glomerulonephritis, tuberculosis, trauma and vasculitis.
Flank pain, costovertabral angle tenderness and renal tenderness to deep palpation may also be associated with cystitis because of referred pain. When it occurs in association with fever and chills, nausea, vomiting and prostration, the clinical diagnosis is pyelonephritis. Internal dysuria is more associated with UTI than external dysuria. In females, external dysuria or a history of vaginal discharge or irritation is more associated with vaginitis, cervicitis or PID than with UTI.
Clinical findings cannot reliably differentiate between upper and lower tract infections. About 30–50% of women with signs and symptoms restricted to the lower urinary tract have silent (or subclinical) infection of the kidney.
Regarding the epidemiology of UTI in children, which ONE of the following is TRUE?
Answer: B: Children with UTI are more likely to have a family history of UTI in first-degree relatives than children without UTI. This may be explained by a genetic predisposition to risk factors such as VUR and the presence of specific blood-group antigens which, when expressed on the surface of urinary epithelium, promote adherence of bacteria.
Up to 10% of girls will have had a UTI by adulthood, with most cases occurring after the age of 2 years. Only 2–3% of boys will be diagnosed with a UTI during childhood and more than 60% of these occur before the age of 2 years. UTIs are an uncommon occurrence in boys older than 4 years of age.
VUR is present in at least 20–30% of children having their first UTI, compared with only 1–3% of the general paediatric population. A single UTI has a relatively high risk of recurrent infections, with various studies showing rates of 15%–40%. Most recurrences occur within 2 years of the initial UTI. Factors REFERENCES 205 associated with recurrence include young age at first UTI, urinary tract abnormalities including VUR, and voiding dysfunction.
Regarding the diagnostic evaluation of a first UTI in children, which ONE of the following statements is TRUE?
Answer: A: Guidelines referring to the appropriate investigations that should be performed in children with a first UTI remain controversial.
It is generally recommended that renal ultrasound should be performed in all young children after an initial febrile UTI, mainly to detect anatomical abnormalities, ureteral and calices dilation and to exclude obstruction. This should ideally be performed within 6 weeks of diagnosis. It is recommended that a renal ultrasound be performed at the time of UTI in the presence of:
MCUG (to detect VUR and posterior urethral valves) may be necessary but the decision to perform this invasive and sometimes distressing investigation needs to be individualised. The value of demonstrating vesicoureteric reflux in assisting future management is controversial. It is currently a matter of clinician preference and can be discussed with the parents at follow-up. It may be done in children under 6 months of age (especially boys), and may be necessary for older children according to circumstances. A DMSA scan is not routinely recommended in all patients. If performed, it should be done after 3–6 months of the UTI to detect renal scarring, as acute pyelonephritis is also associated with photopenia on DMSA scanning. SPA is a simple and safe procedure. It can be performed in children under 2 years of age, as a full bladder in this age group normally sits above the bony pelvis.
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