Acute Pyelonephritis
08.05.13
Dr Andrew Stein
Consultant in Acute and Renal Medicine
Clinical Commissioning Director
Coventry 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% communityacquired 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
Quiz
1. 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
Thankyou
andrew.stein@uhcw.nhs.uk
Acutemed.co.uk Renalmed.co.uk