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ICD 10 definition of urinary tract infections – infections affecting structures participating in the secretion and elimination of urine : the kidneys , ureters , urinary bladder and urethra.
Hw common ? UTI’s are common in pregnancy – they are the most common bacterial infection in pregnancy It may be asymptomatic UTI in pregnancy has been associated with ○ prelabour rupture of membranes ○ preterm labor and delivery ○ clinical and subclinical chorioamnionitis ○ postpartum fever in mother and neonatal infection Pyelonephritis can be life threatening ○ ↑ risk of perinatal and neonatal morbidity ○ preterm delivery and low birth weight
Cause –Pregnant ♀ are at ↑ ed risk of UTIs Beginning in week 6-7 and peaks during weeks 22-24 Physiological alterations in the urinary tract ○ dilatation of the ureters and renal pelvis ○ decreased ureteral peristalsis ○ bladder tone decreases –> increased urinary capacity ○ ↑ urinary statsis and uretrovesical reflux ○ blood volume expansion ↑ GFR and urinary output ○ glycosuria Other factors which may contribute include ○ anatomical changes for eg bladder displacement mechanical obstruction of ureters ○ hyperestrogenism ○ gestational bacterial virulence factors
As per site of infection –Urethra ( urethritis ) Bladder ( cystitis ) Kidney ( pyelonephritis ) Blood stream ( urosepsis ) OR Upper or Lower urinary tract where the kidneys are the threshold between the two levels
Pathogen –E Coli is the commonest cause ~ 80 % – other pathogens include Klebsiella pneumoniae Proteus mirabilis Enterobacter species Staphylococcus saprophyticus Group B beta-hemolytic streptococcus & genital mycoplasm Ureaplasma urealyticum ( rarely causes UTI , but of significance particularly in pregnancy due to association with chorioamnionitis )
Terminology –Asymptomatic bacteriuria ○ positive culture without declared symptoms ○ culture from a single MSU specimen yeilds the same bacterial strain in any trimester in quantitative counts of > 100,000 colony forming units / ml Acute cystitis ○ involves only the lower urinary tract ○ inflammation of the bladder due to bacterial or non-bacterial causes ○ signs and symptoms include hematuria , dysuria , suprapubic discomfort , frequency , urgency and nocturia Pyelonephritis ○ most common UTr complication in pregnant ♀ ○ fever , flank pain and tenderness and sig bacteriuria ○ other symptoms may include nausea , vomiting , frequency , urgency and dysuria
History-Fetal well-being Current symptoms ( urinary and systemic ) Previous h/o UTI –> recurrent episodes more common if previous history Co-existing vaginal discharge ( r/o STI – may have similar symptoms ) Medical history Predisposing factors ( see next box ) Frequency of sexual intercourse New sexual partner Spermicide use Low socioeconomic status
Risk factors – Closely associated with socioeconomic status- UTI occurs in up to 20 % of pregnancies in disadvantaged groups ( Vasquez 2003 ) Diabetes mellitus Recurrent UTI Anatomical abnormalities of the urinary tract Higher parity Sickle cell disease Age less than 15 yrs at first UTI
Examination –Check ○ temp ○ pulse ○ blood pressure ○ respiratory rate ○ oxygen saturation Abdominal examination Try and distinguish between upper and lower UTI – patients with pyelonephritis are ○ sicker ○ may be febrile ( > 38° ) , tachycardic and have renal angle as well as suprapubic tenderness Auscultate fetal heart rate ○ can be done from 12th week Procalcitonin has been shown to be better at predicting acute pyelonephritis than WBC/ CRP
Asymptomatic Bacteriuria – Asymptomatic bacteriuria increases the risk of pyelonephritis in pregnant women- untreated 20-40 % of pregnant women may develop pyelonephritis later in pregnanct Treatment of asymptomatic bacteriuria in pregnancy is indicated and considered an accepted and recommended strategy CKS NHS suggests ○ screen for asymptomatic bacteriuria on the 1st ante-natal visit by sending urine for culture ○ if asymptomatic bacteriuria is found –> send a 2nd urine sample for culture If the 2nd urine culture confirms asymptomatic bacteriuria ○ treat with 7 days with a sensitive antibiotic ○ options when sensitivities are known Amoxicillin 250 mg tds * 7 days Nitrofurantoin 50 mg qds or 100 mg bd MR * 7 days Trimethoprim 200 mg bd for 7 days ( see caution about folate ) Cefalexin 500 mg bd or 250 mg 6 hrly for 7 days Send urine for culture at every antenatal visit until delivery If group B streptococcus is isolated- inform antenatal services
testing –Send urine for culture and sensitivity –> all pregnant women with a suspected UTI ○ before starting treatment ○ seven days after treatment ( test of cure ) Dipstick ○ Nitrite accurately predicts UTI ○ Highly specific but not highly sensitive ○ Leukocyte esterase – is produced by neutrophils and may happen in pyuria ○ Chlamydia and ureaplasma urolyticum may be associated with pyuria and negative urine cultures Negative nitrite and leucocyte esterase can be used to r/o UTI in pregnancy
Choice of antibiotics –Prescribe antibiotics to all women with a suspected UTI during pregnancy- also check local guidance Nitrofurantoin 50 mg qds or 100 mg ( MR ) bd for 7 days ○ avoid in term and breastfeeding ( risk neonatal haemolysis ) It has been used extensively and is considered safe in pregnancy Not appropriate for treating pyelonephritis Trimethoprim 200 mg bd for 7 days ( off label use )- good evidence to support use in pregnancy is lacking – used commonly ○ give folic acid 5 mg daily – first trimester ○ avoid use if folate deficient or taking a folate antagonist ○ avoid in first trimester ( teratogenic ) ○ Breast feeding- safe in short term Cefalexin 500 mg bd or 250 mg 6 hrly for 7 days ○ safe in all stages of pregnancy and breast feeding Amoxicillin 500 mg tds for 7 days ○ safe in all stages of pregnancy and breast feeding ○ increasing resistance Co-amoxiclav 625 mg tds Fosfomycin 3g single dose ( BNF says use only if potential benefit outweighs risk )
Advice / admit –Suspected pyelonephritis –> admit Specialist advice ○ symptoms that fail to respond to appropriate antibiotic Rx guided by urine culture ○ recurrent UTIs
Follow-up-Follow up results in case resistant pathogens are found Repeat urine culture seven days after finishing antibiotic treatment If group B streptococcus is isolated- inform antenatal services If no bacterial growth- consider an alternative cause of symptoms
Why important –UTI in pregnancy is associated with adverse outcomes for the mother and the baby Association with pre-eclampsia Chrioamnionitis -GBS bacteriuria strong association Pre-term delivery ↑ ed risk UTI and neonatal GBS disease Maternal UTI and neonatal UTI – some evidence to show association
LINKS AND RESOURCES
INFORMATION FOR PATIENTS
Health Navigator New Zealand PIL UTI in pregnancy –https://www.healthnavigator.org.nz/health-a-z/u/uti-in-pregnancy/
Baby centre UK https://www.babycentre.co.uk/a536353/urinary-tract-infections-in-pregnancy
American Pregnancy Association https://americanpregnancy.org/pregnancy-complications/urinary-tract-infections-during-pregnancy/
RESOURCES FOR CLINICIANS
Antibiotic and dosage guide from Goucestershire Hospitals NHS Trust https://www.gloshospitals.nhs.uk/gps/antimicrobial-resources/adult-antibiotic-treatment-guidelines-site-infection/urinary-tract-infection-pregnancy/
Management of UTIs in pregnancy in Primary Care from Oxfordshire Commissioning Group https://www.oxfordshireccg.nhs.uk/professional-resources/documents/clinical-guidelines/gynaecology/UTIs-in-pregnancy-january-15.pdf
An article from CDC on choice of antibiotics Ailes EC, Summers AD, Tran EL, et al. Antibiotics Dispensed to Privately Insured Pregnant Women with Urinary Tract Infections — United States, 2014. MMWR Morb Mortal Wkly Rep 2018;67:18–22. DOI: http://dx.doi.org/10.15585/mmwr.mm6701a4external icon.
Western Australia North Metropolitan Health Service Women and Newborn Health service Infections: Urinary Tract infection in pregnant women guideline https://www.kemh.health.wa.gov.au/~/media/Files/Hospitals/WNHS/For%20health%20professionals/Clinical%20guidelines/OG/WNHS.OG.InfectionsObstetricGynaeAntibioticTreatmentUrinaryTractInfection.pdf
World Health Organisation on asymptomatic bacteriuria in pregnancy https://extranet.who.int/rhl/topics/preconception-pregnancy-childbirth-and-postpartum-care/antenatal-care/who-recommendation-antibiotics-asymptomatic-bacteriuria
References
- A likely urinary tract infection in a pregnant woman BMJ 2017 ;357:j1777
- Urinary tract infections in adults NICE guidance QS90 June 2015
- Urinary tract infections ( lower ) – women CKS NHS
- Management of suspected bacterial urinary infection in adults SIGN 88 July 2012
- Treatments for symptomatic urinary tract infections during pregnancy Cochrane Database of Systemic Reviews Juan C Vazquez , Edgardo Abalos January 2011
- Urinary-tract infections BNF May 2017
- Renal Disease in Pregnancy Patient UK
- Guideline on urological infections European Association of Urology- EAU March 2013
- Primary Care Antimicrobial Guidelines All Wales Medicines Strategy Group September 2015
- Urinary Tract Infections During Pregnancy Am Fam Physician. 2000 feb 1;61 (3) :713-720
- Mandell , Douglas and Bennett’s Principles and Practice of Infectious Diseases Updated Edition January 2015
- Urinary Tract Infections in Pregnancy Medscape Emilie Katherine Johnson et al Jul 2016
- Health Protection Agency : uncomplicated urinary tract infections audit in primary care
- BPAC NZ Managing urinary tract infections in pregnancy
- Oxford Maternal and Perinatal Health Institute – Urinary Tract Infections in Pregnancy accessed via https://www.gfmer.ch/omphi/maternal-infections/pdf/UTI-in-pregnancy.pdf