Emphysematous cystitis: an incidental finding with varying outcomes

Abstract

Emphysematous cystitis (EC) is a rare severe urinary tract infection characterised by pockets of air in and around the urinary bladder wall caused by gas-forming organisms. Common predisposing factors are chronic infection, immunosuppression, diabetes and neurogenic bladder. The presentation may vary from mild illness to severe life-threatening cystitis. We report two cases of incidental detection of EC diagnosed on imaging for the evaluation of unrelated symptoms. Although asymptomatic, this lethal disease still warrants prompt recognition and treatment with broad-spectrum antibiotics and urinary bladder drainage to prevent severe morbidity and mortality.

Background

Emphysematous cystitis (EC) is a severe form of complicated lower urinary tract infection. The classical feature is the presence of gas in the urinary bladder wall, predominantly caused by gas-forming organisms, most commonly Escherichia coli and Klebsiella pneumonia. The high-risk factors associated with this potentially fatal condition are chronic urinary infection, neurogenic bladder, long-term urinary catheters, diabetes mellitus and immunosuppression. Common clinical features are fever, dysuria and lower abdominal pain. Computed tomography (CT) imaging is the key diagnostic investigation in most cases. Early diagnosis and focused management with close monitoring, bladder drainage and broad-spectrum antibiotics are key to prevent further spread of infection.

Case history

Case 1

A 41-year-old man was brought by paramedics to the emergency department following an unwitnessed fall from 20 steps of concrete stairs. The patient sustained injuries to the left chest and hip region. On presentation, he complained of pain in the left hip region. There was no loss of consciousness, limb weakness, vomiting, dyspnoea or abdominal pain. He had a past medical history of alcohol-related liver cirrhosis complicated by grade 1 oesophageal varices and ascites, borderline systolic left ventricular dysfunction, pulmonary hypertension, was an ex-intravenous drug user on methadone, and registered partially blind. On initial physical examination, he was drowsy but arousable with a Glasgow Coma Scale (GCS) of E3V5M6. His vital signs were stable with a blood pressure of 124/76mmHg and a pulse of 88 beats per minute. There was extensive bruising of the left lateral chest, flank and hip region. Cardiovascular and pulmonary examination was unremarkable. The abdomen was soft and nontender. There were no signs of focal neurological deficits. Blood analysis showed a marked increase in liver function test from baseline, deranged electrolytes and raised inflammatory markers (C-reactive protein of 34mg/L and white cell count of 14.2 × 10⁹/L). CT head, chest and spine as part of the trauma evaluation was normal. However, the patient’s abdominal CT scan demonstrated localised infiltration of air within the urinary bladder wall with no other major organ injuries (Figure 1). The patient was admitted under the emergency care team and underwent regular monitoring of vital signs. A 16-Fr urethral catheter was placed which showed initially cloudy urine that cleared gradually. A urine sample was sent for analysis and showed E. coli growth. Intravenous piperacillin–tazobactam was commenced. Acute medical team input was provided to optimise hepatic function. At 10 days, inflammatory markers were within normal limits and liver function improved. A follow-up CT abdomen showed complete resolution of gas in the urinary bladder wall (Figure 2). The urine culture was confirmed sterile. The urinary catheter was removed on day 14 and antibiotics were stopped. At 3 months follow-up, the patient remained well.

Figure 1 .

(a) Axial and (b) coronal computed tomography images of 41-year-old man (case 1) showing contrast filling in the urinary bladder on delayed images with a rim of air in the bladder wall suggestive of emphysematous cystitis (white arrows).

Figure 2 .

(a) Coronal and (b) axial computed tomography images on follow-up of 41-year-old man (case 1) showing complete resolution of emphysematous cystitis changes in the bladder wall.

Case 2

An 84-year-old woman presented to the emergency department with a fall following a syncopal episode. There was no history of headache, vomiting, seizures, bleeding episodes or abdominal pain. She had a background history of chronic obstructive pulmonary disease on long-term oxygen therapy, previous cardiac bypass surgery on antiplatelets, osteoarthritis, rheumatoid arthritis and chronic kidney disease complicated with anaemia. On examination, she was orientated and her vital signs were stable. There was bilateral pedal oedema. Respiratory examination revealed widespread expiratory wheeze. Cardiovascular and abdominal examination was normal. The patient was admitted under the emergency medical team for post-fall investigation. During her hospital stay, she developed new-onset difficulty swallowing. A CT thorax, abdomen and pelvis showed a small hiatal hernia. Interestingly, it also revealed a moderate amount of gas surrounding the urinary bladder wall suggestive of EC (Figure 3). Blood analysis showed a white cell count of 16.4 × 10⁹/L, serum creatinine of 415μmol/L and C-reactive protein of 24mg/L. Urine analysis showed full pus cells. A 16-Fr two-way urinary catheter was placed and the patient was commenced on intravenous piperacillin–tazobactam. The patient incurred aspiration pneumonia and her clinical condition deteriorated with worsening renal function. In view of poor survival outcomes due to significant comorbidities and general frailty, no further attempts at resuscitation were recommended and the patient was kept comfortable during her last days. The patient died after 10 days in hospital.

Figure 3 .

(a) Axial and (b) coronal computed tomography images of 89-year-old woman (case 2) showing distended urinary bladder with circumferential foci of gas in the bladder wall (white arrows).

Discussion

EC is an acute inflammatory disease of the urinary bladder characterised by the presence of air within the bladder wall. The true incidence of this condition is not yet known because most articles published in the English literature have been single case reports. However, an increase in EC has been noted due to its detection following incidental findings from cross-sectional imaging, commonly used to evaluate other pathology. Nonetheless, it may remain under-reported because routine imaging is not commonly performed for all urinary tract infections.¹

In our series, both cases were diagnosed incidentally on imaging for assessment of other pathology. EC is more commonly reported in elderly diabetic females with frequent urinary tract infections. Diabetes mellitus is the most common predisposing factor.² Other risk factors are impaired bladder emptying, neurogenic bladder, long-term urinary catheters, immunosuppression, recurrent urinary stones and frequent urinary instrumentations.³ Rarely, it can be associated with urothelial cancer as well.⁴ Huang et al suggested three critical prerequisites leading to EC: the presence of gas-forming bacteria, high local tissue glucose levels and impaired tissue perfusion.⁵ In our series, neither patient was diabetic or had any prior urinary infection. However, one patient had decompensated alcoholic liver disease and the other had autoimmune disease, predisposing to impaired physiology. Thomas et al described that only 7% of EC patients in his series of 135 patients were asymptomatic at presentation and diagnosed incidentally, as seen in our case series.¹ Common nonspecific presenting features include dysuria, haematuria, urinary frequency and urgency. Pneumaturia, although a classical feature, is rarely seen.³ Other rare presenting features include presentations with acute abdomen, diarrhoea, sepsis and subcutaneous emphysema.

Gas-forming organisms leading to a diagnosis of EC include E. coli and K. pneumonia. Other causative organisms are Enterobacter aerogenes, Clostridium perfringens, Candida albicans, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus and Enterococcus faecalis.¹ In our series, E. coli was the causative organism in case 1, whereas no specific organism was isolated in case 2. This may have been due to broad-spectrum antimicrobial cover prior to urine analysis and culture.

Because of the varying and nonspecific nature of case presentations, early imaging may hasten diagnosis. Common early imaging modalities such as a plain abdominal x-ray shows a ring of translucency in the pelvis around the bladder with air fluid levels.⁶ However, the gold standard imaging modality is cross-sectional CT scan. This is highly sensitive and could also aid in confirming other aetiology such as the presence of a vesicocolic fistula, intra-abdominal abscess, malignancy or diverticulosis.⁷

In our series, both patients were diagnosed incidentally with EC following a CT scan. EC is fatal disease with a high risk of progression to bladder necrosis, urosepsis and death, more commonly seen in immunocompromised patients. Prompt diagnosis and treatment are essential to prevent further progression. Management consists of broad-spectrum antibiotics, urinary bladder drainage, adequate hydration and treating the underlying cause. Hyperbaric oxygen may be used as an adjunct mainly owing to its anti-inflammatory properties, angiogenesis and bactericidal effects.⁸ In fewer than 10% cases, surgical debridement, partial or radical cystectomy is required. One patient in our series responded well to intravenous antibiotics and bladder drainage. At 2 weeks, the EC had resolved and patient was doing well. The other patient succumbed to multiorgan dysfunction unrelated to EC.

Conclusions

EC is an unusual complicated urinary tract infection. Although commonly reported in diabetic and immunocompromised patients, it may also be seen in healthy individuals. It can often be seen in asymptomatic individuals, demonstrated incidentally on CT imaging. Prompt recognition, early diagnostic imaging, treatment with antimicrobials and close monitoring may help prevent fatal outcomes.