Makindo Medical Notes

Related Subjects: |Pyelonephritis and Urosepsis (UTI) |Pyonephrosis |Perinephric abscess |Acute Kidney Injury (AKI) / Acute Renal Failure |Renal/Kidney Physiology |Chronic Kidney Disease (CKD)

Acute pyelonephritis is a bacterial infection of the renal parenchyma that often leads to renal scarring

Quick Guide

• Simple UTI in women needs 3 days of antibiotics. Give 7 days for men, pregnancy or catheter (also change catheter)
• Do not treat asymptomatic bacteriuria in non-pregnant patients as it does not reduce morbidity or mortality
• Do not treat patients over the age of 65 based on a positive dipstick alone. Need other symptoms
• If pregnant send a urine culture and treat asymptomatic bacteriuria

About

• 33% of Women experience a UTI at some time but is uncommon in men and requires investigation
• Acute pyelonephritis is a bacterial infection needing treatment with an antibiotic that reaches therapeutic concentrations in the kidney.
• Shorter urethra in women facilitates colonization by faecal flora such as E. coli.

Definitions

• Bacteriuria : bacteria in urine. Pyuria: pus in urine
• Asymptomatic Bacteriuria : No Symptoms and normal bloods and urine culture Bacteria > 10⁵ colony forming units per ml in urine
• UTI: Symptoms/abnormal bloods and urine culture Bacteria > 10⁵ colony forming units per ml in urine

Urinalysis

• Nitrites: suggests gram negative bacteria and more useful than leucocytes
• Leucocytes: measures leucocytes esterase. Usually present but significant rise suggests infection
• If both positive send MSU
• Correlate with symptoms

Aetiology

• Usually passage of local perineal bacteria up the urethra. It may be related to sexual intercourse or low-volume urine
• Renal stones, Stasis in the renal system e.g. bladder diverticula
• Poor bladder emptying e.g. prostatism, neurological disease, Urethral catheterisation, Pregnancy, Diabetes, Immunosuppression

Typical Organisms

• Escherichia Coli 60-80%
• Proteus mirabilis 15% (MAP renal stones)
• Klebsiella aerogenes 20%
• Enterococcus faecalis
• Staphylococcus saprophyticus: seen in young sexually active
• Staphylococcus aureus

Clinical

• Cystitis/Urethritis: Dysuria, smelly urine, frequency, suprapubic tenderness, Haematuria, malaise, flu like symptoms, nausea, delirium
• Pyelonephritis: Flank pain, Renal angle tenderness, Fever, Rigors
• Urosepsis: Tachycardia, Pyrexia, Low BP, Dyspnoea, Fast AF, Delirium

Complications of acute pyelonephritis include impaired renal function or renal failure, sepsis and preterm labour in pregnancy.

Investigations

• FBC: elevated WCC, High CRP
• U&E: may have AKI
• Lactate : elevated in sepsis
• Urinalysis: Blood, leucocytes and nitrites
• Urine culture
• Blood Culture
• Renal USS: exclude stones and abscess and obstruction. Imaging with ultrasound or CT to rule out perinephric abscess should be considered if‚ there is no clinical improvement after 48 hours of‚ appropriate treatment

Complications

• Bacteraemia, sepsis
• Renal abscess
• Renal papillary necrosis
• Chronic pyelonephritis causing scarring and chronic kidney disease

Consider kidney stones as a potential diagnosis if prior colicky pain radiating to the groin, haematuria, or history of‚ stones is present

Management of Pyelonephritis/Urosepsis

• Admit to the hospital if symptoms or signs suggesting a more serious illness or condition e.g. sepsis. Consider specialist advice for admission for people with acute pyelonephritis if significantly dehydrated or unable to take oral fluids and medicines, pregnant, risk of complications e.g. known or suspected structural or functional abnormality of the genitourinary tract or underlying disease (such as diabetes mellitus, or immunosuppression).
• If unwell then ABC. IV fluids and commence IV antibiotics and treat as for sepsis pathway
• Paracetamol IV or PO for pain. Alternative Ibuprofen if required.
• Drink sufficient fluids to avoid dehydration.
• Commence Antibiotics usually for 7-10 days except Trimethoprim
  • Cefalexin 500mg BD or TDS for 7-10 days.
  • Co-amoxiclav (if appropriate in line with culture and sensitivity results) 625 mg TDS for 7-10 days.
  • Trimethoprim (only if appropriate in line with culture and sensitivity results) 200mg BD for 14 days.
  • Ciprofloxacin 500 mg BD for 7 days.
  • Pregnant women not admitted: Cefalexin 500mg BD or TDS for 7-10 days. Higher doses may be given
• Antibiotics if vomiting or severely unwell or sepsis. IV antibiotics should be reviewed by 48 hours and stepped down to oral antibiotics where possible, for a total of 7 days
  • Co-amoxiclav 1.2 g TDS
  • Ciprofloxacin 400 mg BD or TDS
  • Ceftriaxone 1 to 2 g OD
  • Gentamicin 5-7 mg/kg OD
  • Amikacin 15 mg/kg OD
  • Pregnant: Cefuroxime 750 mg TDS or QDS
• If catheter - see catheter-related UTI
• Referral for Men, following a single episode without an obvious cause and Women with recurrent pyelonephritis.
• Refer urgently using a suspected cancer pathway referral for an appointment within 2 weeks for those with haematuria and possible cancer. See NICE
• Consider non-urgent referral for bladder cancer in people aged 60 years and over with recurrent or persistent unexplained UTI.

References

• Pyelonephritis (acute): antimicrobialprescribing NICE guideline Draft for consultation, May 2018