The condition is rare, most commonly presenting in males aged 50-70 years and usually confined to certain patient subgroups 1,2.
Risk factors include 1,2:
- diabetes mellitus (most common)
- liver cirrhosis
- urinary retention (e.g. bladder obstruction, neurogenic bladder)
- indwelling catheterization
- immunocompromised state
- recent instrumentation to the urethra or prostate
Clinical features are non-specific, often with lower urinary tract signs (e.g. dysuria, lower abdominal/perineal pain, increased urinary frequency/urgency) and systemic features of infection (e.g. fever) 1,2. Digital rectal examination is also non-specific, with potential findings including prostatic enlargement, fluctuance, and pain 1,2.
Emphysematous prostatitis is typically a complication of acute bacterial prostatitis, which itself is often a complication of urinary tract infections that ascend to the prostatic ducts 1-3. Causative pathogens are generally Gram negative organisms, such as Klebsiella pneumoniae (most common in one review 1), Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis 1-4.
The gas produced in emphysematous prostatitis may be produced via two mechanisms 1-4:
- necrotic infective tissues fermenting glucose into carbon dioxide
- gas-producing organisms
Features of emphysematous prostatitis can be subtle on conventional radiography and may be difficult to differentiate from normal bowel gas 1-6. Typically, there will be globular regions of increased radiolucency in the area of the prostate, which is characteristically overlying the pubic rami 1-6.
Transrectal ultrasound may be useful in diagnosing emphysematous prostatitis, whereby the prostate will be diffusely hypoechogenic with acoustic gas shadows 1,3,6. However, it may be difficult to differentiate gas shadows from other causes of shadows, such as prostatic calcification 1.
CT is the most commonly utilized modality for diagnosing emphysematous prostatitis, and demonstrates collections of gas within the prostate parenchyma 1-6. Additionally, CT will also reveal features of concurrent acute prostatitis and prostatic abscess, which are both nearly always present 2.
Although less available than CT, MRI is also highly sensitive for demonstrating loculations of gas within prostatic parenchyma and other concurrent pathologies as aforementioned 2,3.
Treatment and prognosis
As it nearly always occurs alongside prostatic abscess, management is identical to that of prostatic abscess. Thus, percutaneous ultrasound-guided or CT-guided transperineal or transrectal drainage is often considered the first choice for therapy, with concurrent broad-spectrum antibiotic coverage 1,2.
The mortality rate of emphysematous prostatitis is 25%, higher than that of non-emphysematous prostatic abscess, and also higher than that of emphysematous pyelonephritis and emphysematous cystitis 1.
History and etymology
The first case was described by Albert J Mariani, an American urologist, and his colleagues in 1983 6.
- 1. Wen SC, Juan YS, Wang CJ, Chang K, Shih MC, Shen JT, Wu WJ, Jang MY. Emphysematous prostatic abscess: case series study and review. (2012) International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 16 (5): e344-9. doi:10.1016/j.ijid.2012.01.002 - Pubmed
- 2. Kuo PH, Huang KH, Lee CW, Lee WJ, Chen SJ, Liu KL. Emphysematous prostatitis caused by Klebsiella pneumoniae. (2007) Journal of the Formosan Medical Association = Taiwan yi zhi. 106 (1): 74-7. doi:10.1016/S0929-6646(09)60219-9 - Pubmed
- 3. Douglas-Moore JL, Turnbull LJ, Moazzam M, Lee ATF, Peracha AM. Emphysematous Prostatitis:. (2012) British Journal of Medical and Surgical Urology. 67 (4): 239-54. doi:10.1002/iub.1366 - Pubmed
- 4. Momin UZ, Ahmed A, Nabir S, Ahmed MN, Hilli SA, Khanna M. Emphysematous prostatitis associated with emphysematous pyelonephritis and cystitis: A case report:. (2016) Journal of Clinical Urology. 5 (5): 371. doi:10.1177/1756283X10363751 - Pubmed
- 5. Wang H-S, Shih M-C. Emphysematous Prostatitis. (2016) The New England journal of medicine. 375 (9): 879. doi:10.1056/NEJMicm1507124 - Pubmed
- 6. Mariani AJ, Jacobs LD, Clapp PR, Hariharan A, Stams UK, Hodges CV. Emphysematous prostatic abscess: diagnosis and treatment. (1983) The Journal of urology. 129 (2): 385-6. Pubmed
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