Prostatic abscess in a 16-year-old adolescent secondary to intraurethral water instillation: A case report and review of the literature

Abstract

While acute bacterial prostatitis is seen occasionally in adult males, the development of a prostatic abscess (PA) is exceedingly rare in pediatric and adolescent populations. When PA does occur in younger patients, congenital anomalies, immune compromise, trauma, or genitourinary instrumentation are commonly associated. We report a unique case of a 16-year-old boy who developed a prostatic abscess after deliberately instilling shower water into his urethra. This report details the clinical presentation, diagnostic workup, and treatment course of this patient, followed by a literature review of the pathophysiology, diagnostic considerations, therapeutic paradigms, and operative management strategies for pediatric prostatic abscesses.

Highlights

• •Pediatric prostatic abscess may occur after retrograde reflux of infected urine or fluid.
• •Persistent symptoms after UTI treatment should prompt reassessment for prostate pathology in males.
• •Confidential, non-judgmental history in adolescents is crucial in recalcitrant cases.
• •Normal vitals and labs do not exclude deep prostatic abscesses.
• •Imaging should be pursued in refractory cases.

1. Introduction

Inflammatory and infectious disorders of the prostate gland are rare in pediatric patients.^1,2 The prepubertal prostate is a small structure lacking the glandular network that typically hosts infections; however, during puberty, the gland undergoes rapid maturation and androgen-driven ductal development.³ In this population, a prostatic abscess (PA) is heavily linked to predisposing factors such as structural urological anomalies, dysfunctional voiding, severe immune compromise, or direct mechanical inoculation.^1,2,4,5 We present a case of a PA in a 16-year-old male caused by retrograde instillation of shower water into the urethra, effectively forcing environmental or distal urethral flora into the mature prostatic ducts and leading to a localized suppurative collection.

2. Case presentation

A 16-year-old previously healthy male presented to the emergency department (ED) with penile and perineal pain, dysuria, and intermittent rigors without fever for three weeks. He was initially evaluated by an outside urgent care facility on the fifth day of symptoms and was treated with outpatient cephalexin (500mg BID) for seven days for a presumed urinary tract infection but without improvement of symptoms. He followed up in an outside ED for new urinalysis testing, which was negative for leukocyte esterase, nitrites, or bacteria. He was prescribed phenazopyridine hydrochloride for lower urinary symptoms and referred to his pediatrician who ordered a prostatic ultrasound. Radiologic impression of the ultrasound was reportedly concerning for a PA. He was started on sulfamethoxazole and trimethoprim, but by day three of treatment, symptoms did not dissipate and the patient developed turbid urine without dysuria. He subsequently presented to our ED where he admitted, though did not specify why, to purposefully introducing approximately 15 mL of shower water into his urethra via a pediatric medication syringe under pressure.

On physical examination, the patient was afebrile with stable vital signs: temperature 37.6 °C (99.7 °F), heart rate 71-100 bpm, blood pressure (123-128)/(62-76). Penile, scrotal, and testicular exams did not reveal any gross or palpable abnormalities. A careful digital rectal examination (DRE) was performed, which demonstrated a moderately-sized, boggy prostate with mild tenderness to palpation without nodularity.

Laboratory workup with a urinalysis revealed turbid, amber-colored urine, pyuria with >182 WBC/HPF, moderate amount of bacteria, moderate leukocyte esterase, and 74 RBC/HPF. Nitrites, protein, and urobilinogen levels were unable to be performed due to intrinsic red discoloration of the patient's urine secondary to previous phenazopyridine administration. However, the patient's urine cultures yielded no growth. Mycoplasma genitalium, Ureaplasma parvum, Ureaplasma urealyticum, Neisseria gonorrhoeae, and Chlamydia trachomatis testing were also performed but returned negative. Blood markers showed a normal white blood cell count (8.0), hemoglobin (14.3), and platelets (261) with a creatinine of 0.84.

A repeat pelvic ultrasound was performed due to the severity of symptoms which demonstrated a heterogeneously enlarged prostate with an ill-defined hypoechoic 2.6 cm × 1.8 cm x 2.8 cm lesion within the prostate (Fig. 1). To further characterize the fluid collection, a CT of the abdomen/pelvis was performed revealing an enlarged prostate containing a multiloculated fluid collection with the largest loculation measuring 3.5 cm × 2.1 cm, confirming the diagnosis of PA (Fig. 2, Fig. 3).

Fig. 1.

Transabdominal ultrasound image demonstrates a complex hypoechoic collection within the prostate (yellow star), containing internal echoes and septations concerning for prostatic abscess.

Fig. 2.

Contrast-enhanced coronal CT image of the pelvis shows a multiloculated fluid collection centered in the prostate (yellow star), consistent with a prostatic abscess.

Fig. 3.

Contrast-enhanced sagittal CT image of the pelvis shows a multiloculated fluid collection centered in the prostate (yellow star), consistent with a prostatic abscess.

The patient was admitted and empirically started on intravenous levofloxacin. A foley catheter was placed and infectious disease was consulted. Multi-disciplinary discussion between infectious disease, urology and interventional radiology decided on conservative management with antibiotics as first-line therapy rather than immediate surgical drainage, given the patient's age and the potential for procedure-related complications, including risk to ejaculatory function and other sequelae. By hospital day two, the patient demonstrated clinical improvement in symptoms, the foley catheter was removed, and he was transitioned to oral levofloxacin for a total duration of four weeks. At his two-week follow-up with his primary care physician, he demonstrated complete resolution of symptoms. The patient was instructed to obtain repeat imaging and follow-up with urology but did not return.

3. Discussion

The rarity of PA in children is attributed to the anatomical immaturity of the prepubertal prostate. In adolescents, the gland undergoes androgen-driven gene upregulation and suppurative infections typically require a mechanism that overcomes the body's natural barriers similar to that of adult patients: i.e. genitourinary manipulation (catheterization, surgery, instrumentation, prostate biopsy); bladder outlet obstruction; immunological deficiencies (HIV, diabetes, hemodialysis, chronic renal failure, cirrhosis); or established infections (acute or chronic bacterial prostatitis).^3,4,6,7 The primary mechanism for PA formation in youths is the retrograde reflux of infected urine or fluid into the ejaculatory and prostatic ducts.^4,6,7 In this case, the pressurized introduction of shower water likely directly bypassed the urethral sphincter mechanisms, artificially mimicking intraprostatic ductal reflux, and inoculating the mature gland.

Diagnosing PA in adolescents can be exceptionally challenging.⁵ Relatively few neonatal and adolescent PAs have been reported.^1,5,8, 9, 10, 11, 12 Patients may present with non-specific systemic symptoms such as a prolonged refractory fever, generalized malaise, and lower urinary tract symptoms (LUTS) (Table 1).^1,3,5,13 Adult literature suggests that up to 90% of patients have leukocytosis or pyuria but this is not well reported in pediatric populations.² Escherichia coli is the most frequent bacterium isolated, but urine cultures may only grow the correct bacterial culprit 50% of the time.^2,9,14

Table 1.

Symptoms reported or observed.

Pediatric Patients	Adult Patients
Fever	Fever
Low back pain	Urinary frequency
Hematuria	Urinary urgency
Pyuria	Urinary retention
Malaise	Dysuria
Sepsis	Hematuria
Staccato pattern uroflow	Incomplete voiding
Headache	Suprapubic pain
Pelvic pain	Perineal pain
Constipation	Tenesmus
Ambulation difficulty	Urethral discharge
	Sepsis

A brief list of symptoms reported in the literature of both pediatric and adult patients. Pediatric patients may present with atypical symptoms compared to adults.^5,8,9,13,15

A high index of clinical suspicion for PA is required when a patient fails to respond to initial empiric antibiotics. Adult literature suggests that hospitalized patients, those with ongoing fevers, or those with recent urinary manipulation who fail to have symptom improvement in 48 hours with conservative antibiotic therapy should undergo workup for PA.^6,14,15 Younger men with no known risk factors for PA need prompt evaluation for underlying comorbidities such as diabetes.^2,14 Digital rectal exam (DRE) may reveal a fluctuant mass but must be performed with extreme caution to avoid precipitating bacteremia or septic shock.^14,16 Fluctuance is thought to be pathognomonic for PA, however the incidence can range from 16 to 88%.^2,6 DRE is not routinely recommended in infants.⁵

In the pediatric population, transabdominal ultrasound is the first imaging modality utilized for diagnosis.⁵ However, advanced imaging is the gold standard for diagnosing a prostatic abscess consisting of CT, MRI, and transrectal ultrasonography (TRUS). Contrast-enhanced CT is a selective modality in pediatric and younger adult populations because of radiation exposure.⁷ Both CT and pelvic MRI can delineate fluid collections, extra-prostatic extension, and associated pyelonephritis. Our case utilized CT for advanced imaging due to lack of timely MRI availability. TRUS is highly useful for both diagnosis (80-100%) and guiding aspiration.^2,7,17 However, TRUS without aspiration can be painful and may not be appropriate for the pediatric population if the PA is < 2 cm.⁷

The successful management of a pediatric PA hinges on achieving adequate source control. For small abscesses (typically <1 cm to 2 cm) or highly stable patients, conservative medical management with prolonged intravenous antibiotics followed by highly lipophilic oral agents (like fluoroquinolones or trimethoprim-sulfamethoxazole) may be sufficient to clear the infection.^{2,4,6,14,15,18} These drugs achieve excellent prostate-to-serum concentration ratios, which is essential as standard beta-lactams are hydrophilic and may not penetrate the prostate stroma sufficiently to maintain the therapeutic treatment levels needed when switching to oral antibiotics.¹⁸

When pediatric prostatic infections progress to a mature abscess greater than 2 cm in diameter, or when the patient is unresponsive to antibiotic therapy alone, minimally invasive surgical drainage may be required to prevent sepsis or septic shock.^15,17 US-guided aspiration (transrectal or transperineal) is heavily favored in modern practice because it is minimally invasive, produces rapid clinical improvement, and provides targeted cultures, although recurrence may occur.^15,19 For severe, multiloculated abscesses, or if repeated aspirations fail, transurethral deroofing/resection of the prostatic abscess may be necessary to allow for continuous dependent drainage.^4,13 Our case, however, demonstrates symptom resolution in a pediatric PA >2 cm in diameter with conservative IV then oral antibiotics without the need for procedural intervention. This highlights the necessity for further investigation into appropriate management guidelines specifically in the pediatric population.

So far, based on our research, only one large retrospective multicentric series study has proposed the idea of using a novel Prostate Abscess Complexity Score based on abscess characteristics of focality, septa, laterality, polarity, diameter, and volume in adults for when to consider advanced interventions for a more individualized, risk-based strategy to guide treatment¹⁹ (Table 2). Besides this proposal, no explicit guidelines exist to best determine how PA should be managed in both pediatric and adult populations, opening the door to variable practice patterns, inconsistencies in management, and potential patient harm.^2,9,13,19

Table 2.

Prostate abscess complexity score.

Variable	Points
Focality	Focal = 1 Multifocal = 2
Septa	Present = 1
Laterality	Unilateral = 1 Bilateral = 2
Polarity	Base = 1 Apex = 2 Base to Apex Extension = 3
Diameter	>3 cm = 1
Volume	>20 cm3 = 1

The Prostate Abscess Complexity Score has been proposed to help identify predictors for additional intervention in prostatic abscess in adults. A score ≥6 had a sensitivity of 73% and specificity of 74% for predicting additional intervention. This has not been studied in the pediatric population. Adapted from Pallares-Mendez et al.¹⁷.

Based on reported cases, with prompt diagnosis, targeted antimicrobial therapy, and appropriate surgical drainage when indicated, the natural course and prognosis for an adolescent prostatic abscess are highly favorable, with most patients achieving complete clinical and radiological resolution.^5,8, 9, 10, 11, 12 However, if the abscess is undiagnosed or inadequately managed with short or poorly penetrating antibiotic courses, the natural course can lead to devastating long-term morbidities such as fistulization and extension into the seminal vesicles and spermatic cord.^5,7 Mortality rates in adults with delayed or neglected PA can range from 1% to 16%.¹⁵

Deep-seated prostatic inflammation can also induce extensive tissue fibrosis, stromal scarring, and ejaculatory duct obstruction.²⁰ In the long term, this scarring can lead to chronic pelvic pain syndrome, painful ejaculation, and elevated risks for male infertility.^4,17 Chronic inflammation also predisposes the patient to the formation of prostatic calculi, which acts as a permanent biological nidus for bacteria and leads to chronic, treatment-resistant infections.⁴ Therefore, comprehensive initial treatment, drainage of significant fluid collections, or other operative options for non-responsive medical management are critical to preserving an adolescent's future urologic and reproductive health.

Our patient had resolution of symptoms after two weeks with conservative Levofloxacin treatment despite the 3.5 cm × 2.1 cm abscess size. Given there was no follow-up with Urology at our institution, long-term morbidities for this specific patient cannot be discussed. Yet, at least one other case report in the literature documents successful conservative treatment with IV antibiotics alone for a large, > 5 cm, PA in an adolescent patient who repeatedly forced contaminated water into their urethra from condoms over the course of several years.⁹

4. Conclusion

This case illustrates a highly unusual etiology of a pediatric prostatic abscess resulting from intraurethral water instillation in an adolescent patient. To our knowledge, it is the second of its kind to be reported from forceful instillation of contaminated water into the urethra and with symptomatic success with conservative antibiotics alone in a PA > 2 cm, though our patient's PA developed from a single forced instillation of water. It highlights the importance of recognizing the vulnerability of the post-pubertal prostate to retrograde fluid inoculation and stresses the importance of obtaining a confidential, non-judgmental history in adolescent patients. As seen in our patient, normal vital signs and white blood cell counts do not exclude deep PAs. Prompt reassessment after failure of antibiotic therapy is additionally crucial. Successful management of pediatric prostatic abscesses relies on a high index of clinical suspicion, use of pelvic imaging, utilization of lipophilic antibiotics capable of deep tissue penetration, and in the case of non-response to empiric antibiotic treatment, consideration of surgical drainage of localized collections to prevent long-term sequelae.

CRediT authorship contribution statement

Austin T. Rasmussen: Writing – original draft, Project administration, Investigation, Formal analysis, Conceptualization. Pranav Shetty: Writing – review & editing, Supervision, Project administration, Methodology, Investigation, Conceptualization. Amon Arora: Writing – review & editing, Investigation, Data curation. Albert S. Lee: Writing – original draft, Supervision, Methodology, Investigation, Formal analysis.

Ethics declaration

This study was performed in compliance with relevant laws, regulatory frameworks and guidelines where the research took place. The UC Davis Institutional Review Board granted an exemption. The authors provided the following explanation: The UC Davis Institutional Review Board reviewed this project and determined it to be exempt under Category 4(iii) pursuant to the institution's Flex policy.

This research follows the CARE guidelines and the CARE checklist.

Disclaimer

The views expressed in this manuscript reflect the results of research conducted by the author(s) and do not necessarily reflect the official policy or position of the Defense Health Agency, Department of Defense, nor the U.S. Government.

Informed consent and ethics approval

Written informed consent was obtained from the patient's guardian and verbal assent from the patient to publish details of this case. The privacy rights of participants have been observed. The UC Davis IRB reviewed this research proposal and deemed it exempt (IRB ID: 2399348-1).

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.