another bubble of trouble…

the case.

43 year old female is brought into your resuscitation bay by the paramedics.  She has a 2 day history of vomiting and diarrhoea on the background of type 2 diabetes and alcohol abuse.  Her son is concerned that she has become increasingly confused despite drinking her usual amount of alcohol.

As she passes by you notice that she is agitated, appears clinically dry and has some black discolouration around her mouth which her son believes to be red wine.

Her vital signs are:

  • Pulse: 170 regular
  • BP: 136/70
  • SaO2: 100% (room air)
  • RR : 40
  • GCS : 14 (E4V5M6)
  • Temp : 40.0*C

There are no family or friends available to provide a collateral history, however the paramedics inform you that she has a history of chronic right upper quadrant pain for which she takes regular codeine.  She does not appear to currently be in pain, but complains of nausea.

She has multiple drug allergies including: penicillins, cephalosporins and metronidazole.  The severity of these allergic responses is unclear.

On examination:

  • agitated yet cooperative.
  • tachypnoeic with no other chest signs.
  • clinically dry.
  • normal heart sounds.
  • abdomen soft with RUQ tenderness.  no evidence of an peritonism.
  • no blood on PR.
  • mild pitting oedema to the ankles.
  • moving all four limbs with good strength – no obvious focal neurological deficit.

[DDET Here is her arterial blood gas…]

[DDET & the formal Electrolytes]

Ketones = 0.1 mmol/L


[DDET Describe & interpret these results…]

  • Severe metabolic acidosis
    • HCO3 9, BE -14 (pH 7.40)
    • Anion Gap:
      • = Na – (HCO3 + Cl)
      • = 124 – (9 + 88)
      • = 27
      • HAGMA (Multifactorial with urea 20.2 & lactate 5.1)
    • Expected pCO2:
      • = (1.5x HCO3) +8
      • = (1.5 x 9) + 8
      • = 21.5 (±2)
    • Actual pCO2 = 15, ∴ potential concomitant respiratory alkalosis 
      • DDx – fever, pain, salicylate toxicity, VQ mismatch etc..
  • Moderate hyperglycaemia
    • However, ketones normal.
  • Mild hyponatraemia
    • Corrected Na = 131
  • Severe renal impairment
    • Creatinine 333, Urea 20.2.
    • ?Acute, ?2* to sepsis/hypoperfusion/dehydration
  • Moderately elevated lactate
    • ?Sepsis driven
    • ?Metformin-related
  • Mild anaemia


Severe high-anion gap metabolic acidosis with a concomitant respiratory alkalosis and an associated hyperglycaemia, hyponatraemia and mild anaemia.

Likely secondary to sepsis and associated acute kidney injury.



[DDET What are your differential diagnoses in this case?]

  • Sepsis
    • Gastroenteritis
    • Biliary
    • UTI
    • Pyelonephritis
  • Gastrointestinal
    • Pancreatitis
    • GI bleed
  • Metabolic / Endocrine
    • Hyperglycaemic Hyperosmolar State
  • Toxins
    • Ethanol poisoning (or toxic alcohol)
      • or acute withdrawal state
    • Paracetamol poisoning
    • Iron overdose
    • Mixed overdose
    • Metformin-induced lactic acidosis


[DDET Here are the remainder of her results…]

  • Non-specific, slight LFT derangement.
  • NB. Calculated osmolality = 296, ∴ no significant osmolar gap.

  • Again, mild anaemia noted.
    • Macrocytosis (MCV 105) suggestive of chronic alcohol excess, however consider B12 or folate deficiency.
  • Normal WCC with mild lymphopenia.

  • Elevated INR without anticoagulation therapy.
    • Suggestive of mild liver disease or early coagulopathy from sepsis.


[DDET What are your initial resuscitative goals?]

  • Optimise perfusion.
    • IV access
    • Fluid resuscitation
      • 0.9% Saline, 500ml-1000ml boluses
    • Maintain SBP >100 mmHg (MAP >65 mmHg)
      • May require vasopressors to achieve this
    • Aim for lactate clearance (>10% per hour), improved skin perfusion & normalisation of pulse/blood pressure.
    • Strict fluid balance
    • Aim for urine output of 0.5-1 mL/kg/hr.
  • Treat underlying sepsis
    • Early administration of broad-spectrum antibiotics
    • Identification of source
    • Source control if possible
  • Manage hyperglycaemia
    • Observe response to fluid bolus
    • Further control with insulin infusion
    • Cease oral hypoglycaemic agents
  • Detect other underlying illness
    • Screen for toxins: ethanol, paracetamol + salicylate levels requested
    • Further imaging requested: CT Brain plus CT abdomen/pelvis.
  • Supportive care:
    • Antiemetics
    • Antipyretics
    • Analgesia if required
    • Temperature control
    • Gentle sedation if required
    • Update family
  • Referral for ICU bed.


[DDET The case continues…]

An indwelling catheter is placed and a small amount of cloudy urine is collected. Urinalysis demonstrates moderate blood, moderate leukocyte esterase but negative nitrites.

After initial resuscitation, she remains haemodynamically stable and appears to be slightly less confused, however during the wait for further imaging her blood pressure drops to 70/51 which is no longer responsive to fluid administration.

Peripheral inotropes are started whilst central access is obtained under gentle sedation.

Eventually, you obtain an abdominal CT…


[DDET Here is the CT abdomen…]

[DDET & the formal report…]

There is a markedly abnormal appearance of the right kidney. There are extensive bubbly and linear streaks of gas throughout the majority of the renal parenchyma. There is also significant right peri-renal and peri-ureteric stranding. No definite collections can be appreciated on this non-contrast scan. No definite renal calculi are seen.

Appearances are consistent with extensive right emphysematous pyelonephritis which is thought to be Type I due to the extensive parenchymal involvement.

emphysematous pyelonephritis
Right sided emphysematous pyelonephritis



[DDET The Diagnosis]

Emphysematous Pyelonephritis

– sepsis + delirium
– significant metabolic acidosis with respiratory alkalosis
– acute kidney injury

Emphysematous pyelonephritis is a necrotising, gas-producing infection of the kidney.  The common instigators are E. coli, Klebsiella pneumoniae and Proteus mirabilis. The pathogenesis is poorly understood, but elevated tissue glucose levels are thought to promote a favourable environment for gas-forming microorganisms. 

Risk factors:

  • Diabetes mellitus
  • Female
  • Age >60
  • Urinary tract obstruction

Clinical features:

Clinical features resemble those of acute, severe pyelonephritis. 

Thrombocytopenia, acute kidney injury, disturbance of consciousness or septic shock are commonly seen.


CT is the most definitive modality for diagnosis.  Contrast-enhanced CT is preferable, but may not be possible due to renal impairment.

Prognostic classification:

Emphysematous pyelonephritis can be categorised via two radiological classification systems.


CT features of emphysematous pyelonephritis differentiates into two types:

  • Type 1
    • greater than one-third renal parenchymal destruction
    • streaky or mottled appearance of gas
    • intra- or extrarenal fluid collections are characteristically absent
    • it is usually more aggressive and lead to death shortly, if not intervened early
    • mortality 70%
  • Type 2
    • destruction of less than one-third of the parenchyma
    • renal or extrarenal collections associated with bubbly or loculated gas, or gas within pelvicalyceal system or ureter
    • mortality 20%

Secondly into four classes based on the Huang-Tseng CT classification);

emphysematous pyelonephritis
Huang-Tseng CT classification of emphysematous pyelonephritis

Acute kidney injury, altered mental status and severe hyponatraemia are all significantly associated with mortality.


Treatment is fast becoming increasingly conservative.  Systemic antibiotics are the mainstay of management, in addition to percutaneous catheter drainage (PCD) or stenting to relieve any urinary tract obstruction.

Patients who either have severe radiological disease (class 3A or 3B) or multiple organ dysfunction have been shown to have better outcomes with nephrectomy.  If PCD is unsuccessful, nephrectomy is indicated.


[DDET The case concludes…]

You call the urology team who take the patient to the theatre for an emergency right-sided nephrectomy.

Given her complex medication allergies, Infectious Diseases are consulted who advise clindamycin and ciprofloxacin for ongoing antimicrobial coverage. This is later changed to meropenem.

She remains in intensive care for 48 hours post-op for inotropic support, following which she makes a progressive & uneventful recovery.


[DDET References and Credits]


  1. emphysematous urinary tract infections – uptodate.com

  2. gas-forming infectionsLife in the Fast Lane

  3. Emphysematous pyelonephritis – radiopaedia.org

  4. Huang JJ, Tseng CC. Emphysematous pyelonephritis : clinicoradiological classification, management, prognosis and pathogenesis. Arch Intern Med 2000 Mar 27;160(6): 797-80

  5. Sanford et al. Emphysematous pyelonephritis : the impact of urolithiasis on disease severity. Transl Androl Urol. 2016 Oct; 5(5): 774-779

  6. Saadi A et al. Results of conservative management of emphysematous pyelonephritis. Nephrol Ther 2016 Dec; 12(7): 508-515

  7. Sharma et al. Emphysematous pyelonephritis : Our experience with conservative management in 14 cases. Urology Annals 2013; 5(3): 157-162

Author: Ming-Li Hodder
Web editing + additional writing: Chris Partyka



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