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

Thankyou

andrew.stein@uhcw.nhs.ukAcutemed.co.uk Renalmed.co.uk