Acute Pyelonephritis08.05.13
Dr Andrew SteinConsultant in Acute and Renal Medicine
Clinical Commissioning DirectorCoventry and Rugby CCGs
Structure of Talk
• Definition
• Clinical Features
• Investigation
• Radiology
• Treatment
• Referrals
• Quiz
Choices
• Renal US/not
• Admit/not
• Renal referral/not
Definition and Diagnosis
• Acute pyelonephritis = ascending bacterial infection of the renal pelvis and the renal parenchyma usually presenting with fever, loin pain and bacteriuria
• 'Pyelonephritis': from Greek πήληξ – pyelum, meaning 'renal pelvis', νεφρός – nephros, meaning 'kidney' and -itis, meaning 'inflammation')
• Clinical diagnosis; no single diagnostic clinical feature or investigation
Risk Factors• DM
• Female sex, pregnancy, intercourse
• Stones, bladder catheter, structural renal tract abnormality
• Chronic liver disease
• IV drug use
• Infective endocarditis
Classification:Complicated vs Non-Complicated UTI
• UTI can be 'complicated' eg acute pyelonephritis
• This can be the first presentation of a (treatable) structural disease of the urinary tract, or diabetes mellitus
• Assume all men, children, pregnant women and ill patients, have a complicated UTI; and exclude a structural cause
• In a man, the diagnosis of UTI should be confirmed with a MSU, as it is an important diagnosis
Structural Renal Disease
Not requiring surgery
•Reflux nephropathy
•Polycystic kidney disease
•Duplex system
Requiring surgery (Obstruction)
•Pelvi-ureteric junction (PUJ) obstruction
•Renal stones
•Prostatism
Organisms• Escherichia coli is the commonest organism (80% community-
acquired but <40% hospital-acquired)
Note: other organisms (below) more associated with structural abnormalities:
• Proteus mirabilis 20%
• Staphylococcus saprophyticus 10%
• Klebsiella 5%
• Other organisms include: Streptococcus faecalis, Enterobacter, Acinetobacter, Pseudomonas aeruginosa, Serratia marascens, Candida albicans, Staphylococcus aureus
Note: TB classically causes a sterile pyuria
Symptoms• 75% have preceding
lower urinary tract symptoms
• Loin pain
• Back pain
• Fever/rigors
• Other manifestation of severe sepsis
Note: symptoms can develop over hours, or a day
Signs• Pyrexia
• Loin tenderness
• Rarely, a palpable loin mass
• Scoliosis concave towards the affected side
• Of severe sepsis
• Of AKI (rare)
Note: in prostatitis, there may be a swollen and tender prostate
Investigations (Blood and Urine)• FBC, ESR, CRP
• U+E, LFT, Bone, Glucose (may be first presentation of DM)
• BC (20% +ve)
• Urinalysis: haematuria, proteinuria and be positive for nitrites and leucocytes; usually but not always positive
• MSU: pure growth of >10x5 is diagnostic (60% +ve); pyuria = > 20 WC, on microscopy
Investigations: Radiology
• CXR (Erect: subdiaphragmatic gas?)
• Renal Ultrasound (not unless male, pregnant, child, recurrent, unclear diagnosis or ill)
• CT (Emphysematous Pyelonephritis)
• CT-KUB (Stone?)
Emphysematous Pyelonephritis• This is rare but life-threatening, mainly seen in patients with
poorly controlled diabetes (90% have DM)
• Necrotising infection of the renal parenchyma and its surrounding areas that results in the presence of gas in the renal parenchyma, collecting system, or perinephric tissue.
• 50% mortality
• 70% E Coli 70%
• Classic finding is gas within the body of the kidney (CT)
• Bilateral nephrectomy may be necessary (really!)
CT abdomen
Investigation – Urinary Dipstick
3 False beliefs•Protein – nil ≠ no proteinuria (= no albuminuria)•Protein + ≠ UTI•‘Pos dip’ = UTI
True belief•Protein ≥ +++ = glomerular/interstial disease, ++ might be
Differential Diagnosis
• Renal colic
• Pelvic inflammatory disease
• Acute appendicitis
• Acute cholecystitis or diverticulitis
• AAA
Treatment: Antibiotics• Uncomplicated: PO TRIMETHOPRIM
200 mg bd
• Complicated: IV GENTAMICIN 5 mg/kg od
+ IV CO-AMOXICLAV 1.2 g tds
• ± Analgesia
Treatment: Other
• ABG/VBG
• Sepsis Six
• ICU
Treatment: In or outpatient
• IV Cetotaxime 1g OD
• Follow-up
• GP
• Renal / not
Who to Refer to Nephrology or Urology
• Complicated (some)
• Recurrent or unclear diagnosis
• Pregnant woman
• Young (child)
• Male
• Unwell
Ie, considering diagnosis structural renal disease .. if doing Renal US, refer
Complications + Indications for Surgery• Renal cortical abscess (renal carbuncle)
• Renal corticomedullary abscess: Incision and drainage, nephrectomy
• Perinephric abscess: Drainage, nephrectomy
• Calculi-related urinary tract infection (UTI): Extracorporeal shockwave lithotripsy (ESWL) or endoscopic, percutaneous, or open surgery
• Renal papillary necrosis: CT guided drainage or surgical drainage with debridement
• Emphysematous pyelonephritis: Nephrectomy
Quiz1. 20% of patients have a positive BC
2. 20% pf patients have a positive MSU
3. Urinalysis: ‘protein – nil’ = no proteinuria
4. All patients need a Renal US
5. Klebsiella is the commonest organism
Summary
• Acute pyelonephritis is relatively easy diagnosis
• 3 Big decisions ..
• Renal US or not
• Out vs Inpatient?
• Refer to Renal/Urology or not
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