Pyelonephritis

Introduction

Urinary tract infections are very common especially in women. It is more common in women who are older or who are sexually active. In males occurrence of UTI is very rare after infancy. As men get older and have increasing prostatic disease UTI’s become much more common.

 

UTI is a non-specific term and may refer to a number of conditions including asymptomatic bacteriuria, urethritis, cystitis, and pyelonephritis (infected kidney). Patients with pyelonephritis are at risk of bacteraemia and sepsis and therefore need rapid treatment with appropriate antibiotics

 

Causative Agents = GI Organisms

·      E.coli (commonest), Klebsiella, Proteus, Enterobacter, Pseudomonas spp

Clinical Features

 

Symptoms

  • Chills and rigors are common. Fatigue. Malaise

  • Pain

    • usually in the affected flank or costovertebral angle +/- suprapubic. Pelvic or Perineal dysuria.

  • GU Symptoms

    • dysuria, frequency, urgency, passing small volumes

  • GI Symptoms

    • Nausea + Vomiting is common, diarrhoea

  • Elderly patients

    • May present with non specific signs e.g. decreased appetite, decreased mobility, increase confusion, lethargy etc

Signs

  • Signs of Sepsis

    • Fever, Tachycardia, Hypotension, tachypnoea

  • Abdomen

    • Flank, costovertebral or suprapubic tenderness

  • Sexually active women – may warrant a pelvic exam if ? PID.

    • PV discharge, adnexal tenderness, cervical excitation

  • Men may warrant PR exam

    • looking for tender prostate = prostatitis

 

Differential Diagnosis

 

Urinary

  • cystitis

  • renal colic

  • infected obstructed kidney

 

Bowel

  • Diverticulitis

  • Colitis

  • Appendicitis

  • Inflammatory bowel disease

Female

  • Pelvic Inflammatory Disease

  • Septic abortion

  • Ovarian cyst

  • Tubo-ovarian abscess

 
 

Biliary

  • Cholecystitis

  • Cholelithiasis

  • Choledocholithiasis

  • Cholangitis

Male

  • Prostatitis

 
 
 

Respiratory

  • Lower lobe pneumonia

  • Empyema

  • PE

 

Clinical Investigations

 
IMG_5491.jpg

Bedside

  • Urinalysis

    • Presence of leucocytes = PPV 50%, NPV 92%,

    • Nitrites = +ve if Gram Negative infection. High PPV. Low NPV as nitrites not produced by Gram +ve bacteria, enterococcus + pseudomonas

  • Urinary BHCG in all women of child bearing age

  • VBG – if concerned re sepsis.

  • POCUS – experienced operator. Looking for hydronephrosis or signs of pyelonephritis

 
IMG_5608+%281%29.jpg

Laboratory

  • MSU

    • WCC > 10,000 = Pyuria

    • Urine Culture

  • Blood Culture if concerned for Sepsis

  • FBC – High WCC,

  • CRP – elevated

  • U&E -? AKI if dehydrated, septic, obstructed

  • LFT + Amylase – out rule other causes

pyelonephritis-2.jpg

Radiology

  • Imaging not indicated in mild cases

  • Renal Ultrasound

    • normal in 75% cases of pyelonephritis but useful in showing complications e.g. abscess, hydronephrosis, renal infarction

  • CT

    • more sensitive especially if concerned regarding stone or obstruction

Management and Disposition

** Don’t forget the Sepsis 6 within 1 hour of presentation

 

Initial Resuscitation

  • IV Fluids as clinically indicated

    • If evidence of sepsis titrate to U/O, BP and lactate.

  • Consider IV vasopressor if severe sepsis and no response to initial fluid resuscitation

 

Specific Treatment

  • Antibiotics as per local guidelines

    • E.g.

      • Uncomplicated Cystitis = Nitrofurantoin 50mg QDS PO x 1/52

      • Recent Treatment/Hospitalisation = Co-amoxiclav 625mg PO TDS x 1/52

      • Pyelonephritis = Co-amoxiclav 1.2g IV TDS + Amikacin 15mg/kg IV

Symptomatic Treatment

  • IV Analgesia and anti-emetic as indicated

  • Antipyretic if patient significantly symptomatic with fever

 
 

Disposition

  • Mild cases of pyelonephritis can be managed in the community with PO antibiotics.

  • If vomiting or systemically unwell/signs of sepsis patient needs to be admitted medically for intravenous antibiotics and IV fluids

References

1.    Cameron et al. Textbook of Adult Emergency Medicine 4th Edition. Chapter 9.4 Urinary Tract Infections

2.    https://radiopaedia.org/articles/acute-pyelonephritis-1?lang=us

3.    SJH Prescribers Capsule. Empiric antimicrobial guidelines. Genitourinary

4.    Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 28838

This blog post was written by Dr Deirdre Glynn and was last updated in October 2020

 Before you go have another look at the clinical case and see have your answers to any of the questions changed and if so how?