Urinary Tract Infections.pptx

Infection

1. Dr Mashanga Urinary Tract Infections

2. Outline Introduction Clinical Presentation – Signs and Symptoms Bacterial and Host Factors Clinical Evaluation-History and Examination Diagnosis and Therapy Special Investigations What is a complicated UTI Treatment Summary

3. INTRODUCTION UTI is best defined as significant bacteriuria of a clinically relevant uropathogen in a symptomatic patient. Most patients with UTI also have pyuria , although there are exceptions Once the diagnosis of UTI is made, it is classified according to location and severity tissue invasion Acute pyelonephritis is an infection which involves the bacterial invasion of renal parenchyma Acute cystitis is an infection limited to superficial invasion of the bladder The term ‘‘asymptomatic bacteriuria’’ refers to the presence of infected urine which produces no clinical symptoms

4. INTRODUCTION UTIs are relatively common in infants and young children The risk before puberty is 3–5% in girls and 1–2 % in boys In young febrile infants aged less than 24 months the prevalence is 3–5 % Prevalence is different depending on age and gender

5. INTRODUCTION Subgroup Risk Males younger than 1 year 3% males older than 1 year 2% Females younger than 1 year 7% females older than 1 year 8% Data show a strong risk reduction among circumcised males: the prevalence of UTI among febrile male circumcised infants is 0.2%.

6. INTRODUCTION UTIs may serve as an important marker of structural or functional urinary tract abnormalities. Vesico ureteral reflux (VUR) is the most common abnormality heralded by UTIs UTIs may be the first symptom of obstructive uropathy or bladder dysfunction

7. CLINICAL PRESENTATION……signs and symptoms (YOUNG CHILD) In infants and young children, UTI usually presents with nonspecific symptoms and signs ( eg , fever, irritability ) Fever may be the sole manifestation of UTI in infants and children <2 years of age In observational studies, UTI is more common among infants and young children with maximum temperatures ≥39°C than in those with lower fevers 16 versus 7% for infants ≤60 days and 4 versus 2% for children <2 years

8. Specific Clinical Signs of UTIs in Neonates and Infants They include Fever Poor feeding failure to thrive Abdominal pain, Haematuria malodorous urine Jaundice may be an early diagnostic sign of UTI in infancy Garcia et al . found UTIs in 7.5% of asymptomatic, afebrile jaundiced infants younger than 8 weeks old UTI should be considered in all infants and young children 2 months to 2 years of age with unexplained fever All UTIs in this age group (particularly with high fever) should be considered as pyelonephritis until proven otherwise .

9. CLINICAL PRESENTATION……signs and symptoms……….Older children Symptoms and signs of UTI in older children include Fever Urinary symptoms (dysuria, urgency, frequency, new-onset incontinence) Abdominal pain Suprapubic tenderness Costovertebral angle tenderness The constellation of fever, chills, and flank pain is suggestive of pyelonephritis in older children

10. Bacterial and host factors that predispose to infection Infecting organism Infecting organisms other than E. coli are more likely to be associated with structural abnormalities of the renal tract UTI is usually the result of bowel flora entering the urinary tract via the urethra , except in the newborn, when it is more often haematogenous The commonest organism to do this is E. coli, followed by Proteus and Pseudomonas sp. The virulence of E. coli is determined by factors including its cell wall antigens , and possession of endotoxin and cell wall appendages called P-fimbriae , which allow the organism to attach to the ureter and ascend to the kidney

11. Bacterial and host factors that predispose to infection Infecting organism Proteus infection is more commonly diagnosed in boys than girls, possibly because of its presence under the foreskin, and predisposes to the formation of phosphate stones by splitting urea to ammonia and thus alkalinizing the urine. Pseudomonas infection may indicate a structural abnormality in the urinary tract affecting drainage.

12. Bacterial and host factors that predispose to infection Incomplete bladder emptying Is the most important cause of UTI and may be due to : Infrequent voiding, resulting in bladder enlargement Vulvitis or balanitis Hurried micturition Obstruction by a loaded rectum from constipation VUR

13. Bacterial and host factors that predispose to infection Vesicoureteric reflux (VUR) Retrograde passage of urine from the bladder into the upper renal tract Primary VUR is a developmental anomaly of the vesicoureteric junction (VUJ) Secondary VUR may be due to or associated with bladder pathology, e.g. a neuropathic bladder or urethral obstruction or occur temporarily after a UTI. High-pressure VUR in this situation, with or without infection, may damage the kidneys.

14. CLINICAL EVALUATION….History The history of the acute illness should include documentation of The height and duration of fever Urinary symptoms (dysuria, frequency, urgency, incontinence) Abdominal pain Suprapubic discomfort Back pain Recent illnesses and antibiotics administered Sexual activity (where applicable)

15. CLINICAL EVALUATION….History The past medical history should include risk factors for UTI, including: Chronic urinary symptoms – Incontinence, lack of proper stream, frequency, urgency , withholding maneuvers (suggestive of bladder dysfunction) Bowel and bladder dysfunction, including chronic constipation Previous UTI or previous undiagnosed febrile illnesses in which urine culture was not obtained Vesicoureteral reflux ( VUR) Family history of frequent UTI, VUR, and other genitourinary abnormalities Antenatally diagnosed renal abnormality

16. CLINICAL EVALUATION….Examination Important aspects of the physical examination in the child with suspected UTI include: Documentation of blood pressure and temperature Temperature ≥ 39°C is associated with acute pyelonephritis that may cause renal scarring Elevated blood pressure may be an indication of renal scarring Growth parameters Poor weight gain may be an indication of chronic kidney disease due to renal scarring Abdominal and flank examination Suprapubic and costovertebral angle tenderness is associated with UTI Enlarged bladder or kidney may indicate urinary obstruction and palpable stool in the colon may indicate constipation, both of which predispose to UTI

17. CLINICAL EVALUATION….Examination Examination of the external genitalia for anatomic abnormalities Phimosis,hypospadias or labial adhesions and signs of vulvovaginitis , vaginal foreign body, or sexually transmitted infections, which may predispose to UTI Evaluation of the lower back for signs of occult myelomeningocele which may be associated with a neurogenic bladder and recurrent UTI Midline pigmentation , lipoma , vascular lesion, sinus, tuft of hair, Evaluation for other sources of fever Another source of fever decreases the risk of UTI but does not eliminate it altogether

18. Diagnosis and Therapy of Childhood UTIs There are four main steps in the clinical management of UTIs in childhood: Diagnosis of UTI Determination of the site of the infection Search for the cause of the UTI Treatment

19. Diagnosis of UTI Definitive Diagnosis is cardinal to avoid complications or unnecessary Tratment False-positive diagnoses are frequent in infants and small children because reliable collection of urine specimens without contamination is difficult False negative diagnosis dramatically increases the risks of renal scarring and its attendant morbidity: Hypertension Complications of pregnancy in women ESKD

20. How to Obtain a Urine Sample Children who are not toilet trained Catheterization Suprapubic aspiration Urine obtained in a sterile collection bag should not be used for culture Children who are Toilet Trained Clean-catch mid-stream urine (can be as accurate as Supra-pubic aspirate if done properly) Preferred for collecting urine for dipsticks and M/C/S

21. Relative Risk of Contamination based on method of collection Method of Urine Collection Risk of urine culture contamination Suprapubic aspiration (SPA) (Gold Standard) 1% Transurethral bladder catheterization (TUBC) 6-12% Clean catch voided urine (stimulation technique or bag specimen) 16-63%

22. Result Interpretation Dipstick analysis Dipstick tests are convenient, inexpensive, and require little training for proper usage ( 88% sensitive ) Parameter Result Significance Leukocyte Esterase Positive suggestive of UTI but is nonspecific Nitrite Positive UTI is likely

23. Significant Bacteriuria by Urine Collection Method Method of Urine Collection Significant Growth for single Uropathagen Significant growth if second uropathogen present Contamination Clean-voided sample ≥100,000 CFU/mL ≥100,000 CFU/mL of one uropathogen and <50,000 CFU/mL of a second uropathogen a second uropathogen with ≥50,000 CFU/mL or growth of >2 organisms Catheter sample ≥50,000 CFU/mL ≥50,000CFU/mL of one uropathogen and <10,000 CFU/mL of a second uropathogen A second uropathogen with ≥10,000 CFU/mL or growth of >2 organisms Suprapubic sample ≥1000 CFU/mL

24. Clinically relevant uropathogens Escherichia coli – accounts for 60-80% of UTIs in paediatrics Other significant uropathogens include: Klebsiella   spp Proteus   spp Enterobacter   spp Citrobacter   spp Serratia marcescens Staphylococcus saprophyticus Enterococcus   spp Streptococcus agalactiae Pseudomonas aeruginosa

25. Clinically irrelevant   uropathogens The following are not considered clinically relevant uropathogens   Lactobacillus   spp Coagulase-negative staphylococci Corynebacterium   spp

26. Pyuria Pyuria is defined by one of the following (irrespective of urine SG): Positive leukocyte esterase (≥trace) on dipstick analysis ≥ 5 WBC/ hpf with standardized or automated microscopy ≥ 10 WBC/mm 3  on a hemocytometer with an enhanced urinalysis The presence of WBC in the urine is not specific for UTI. Causes of pyuria that mimic UTI in children include: Appendicitis Group A streptococcal infection Kawasaki disease

27. Special Investigations Ultrasound Excellent for the detection and measurement of hydroureteronephrosis , renal masses including tumours , renal cystic disease and calculi (including non-radio-opaque calculi) Allows for evaluation of the bladder wall and lumen including measurement of pre- and post-micturition bladder volumes Micturating cystourethrogram Gold standard investigation to detect and grade VUR and posterior urethral valves DMSA ( 99 Tcm dimercaptosuccinic acid) scan The gold standard investigation for the detection of renal cortical scarring. May also be helpful in identifying ectopic kidneys and confirming non-function (e.g. in the MCDK). Information is also generated about differential renal function (the relative contribution of each kidney to total renal function).

28. Special Investigations Dynamic renography ( 99m Tc -DTPA or 99m Tc-MAG3 scans) These scans are used to assess renal blood fl ow , and to detect the presence and site of urinary tract obstruction DTPA is excreted by glomerular filtration and, therefore, gives additional information about GFR. MAG3 is excreted primarily via proximal tubular therefore its clearance is a measurement of tubular cell function.

29. What is Atypical UTI? NICE guidelines define atypical UTI as Seriously ill child. Poor urine fl ow . Abdominal or bladder mass. Raised plasma creatinine level. Septicaemia . Failure to respond to treatment within 48 h. Non- E. coli UTI This is important as the presence of atypical UTI affects the subsequent radiological investigations that are recommended

30. TREATMENT-general measures Treatment is based on the location of the UTI cystitis and pyelonephritis require different treatment A child with a symptomatic UTI should be given antibiotics without delay on empirical basis Before the beginning of the treatment a urine sample must be acquired to isolate the bacteria causing the UTI and to define any antimicrobial resistance A delay in treatment has been identified as a major risk factor in renal scarring with pyelonephritis.

31. Summary UTI diagnosis is important to ensure adequate treatment of the patient Clinical manifestations my be nonspecific in infants and young children Lower Urinary Tract symptoms are seen in older children Identifying the site of infection is important as management of pyelonephritis and cystitis is different UTI might be the initial presentation of renal anatomy abnormalities Atypical UTI is likely to be associated with CAKUT (Congenital Anomalies of the Kidney and Urinary Tract)

32. Reference UpToDate Oxford Handbook of Paediatric Nephrology Paediatric Nephrology 6 th Edition