Large anterior urethral calculus masquerading as periurethral abscess

Abstract

Urethral calculus causes variety of symptoms from simple dysuria to acute urinary retention. The diagnosis is many times not easy. A plain X-ray of the pelvis may aid in diagnosis. Due to variety of symptomatic presentations sometimes it is not the first diagnosis that comes to one’s mind. Management is by removal of the calculus via various methods ranging from endoscopic to open surgery. We present the case of an adult male, who was initially thought to have periurethral abscess due to stricture urethra but during investigations was found to have urethral calculus as the cause for his symptoms.

Background

Urethral calculus (UC) may become a significant cause of morbidity for the patient. Diagnosis of a calculus impacted in the urethra may be readily apparent, but sometimes may not be possible initially due to varying clinical presentations. We present the case of a young male whose clinical presentation was that of a periurethral abscess due to stricture urethra but later found to have a UC.

Case presentation

A 45-year-old man had suffered from thin urinary stream and dysuria for 8 years. He presented with acute onset of penile swelling and severe difficulty in urination for the last 2 days to a primary care physician. There he was examined to have phimosis so a dorsal slit of the preputial skin was done. After the procedure, there was purulent discharge from the surgical wound along with persistent voiding symptoms for which the patient was referred to us for further management. The patient had history of suprapubic cystolithotomy for a vesicle calculus 20 years ago. On examination, there was gross penile swelling up to penoscrotal junction associated with thickened and oedematous penile skin and a normal meatus (figure 1A). There was also an associated tender and indurated swelling located near the penoscrotal junction (figure 1B), palpation of which resulted in purulent discharge from the sutured wound on the preputial skin. A provisional diagnosis of stricture urethra resulting in a periurethral abscess was made. A suprapubic cystostomy was done under ultrasound (US) guidance as initial management. Intravenous antibiotics as per local sensitivity pattern (piperacillin plus tazobactam 4.5 g three times per day) were started.

Figure 1.

(A) Thickened penile skin with normal urinary meatus. (B) Swelling near the penoscrotal junction.

Investigations

Blood investigations including renal function tests were normal. Microscopic examination of the urine showed plenty of pus cells and Escherichia coli was found on culture which was sensitive to piperacillin plus tazobactam, carbapenems, colistin and polymyxin-B. US abdomen revealed thickened bladder walls with normal upper tracts. A retrograde urethrogram (RUG) was carried out for imaging the urethra. The plain X-ray film showed a large elliptical radio-opaque shadow in proximal penile urethra of approximately 2.5 cm length (figure 2). RUG revealed contrast passing around the UC into the dilated proximal urethra (figure 3). Urethroscopy with a flexible cystoscope confirmed the presence of a calculus proximal to the stricture present in the penile urethra and it was not possible to negotiate the scope beyond the stricture (figure 4). The calculus was probably a primary UC formed due to urethral stricture disease. Metabolic workup including serum calcium and parathyroid hormone was within normal limits.

Figure 2.

Plain X-ray pelvis showing the urethral calculus.

Figure 3.

Retrograde urethrogram (RUG) demonstrating contrast around the calculus and dilated proximal urethra.

Figure 4.

Urethroscopy showing stricture distal to the calculus.

Treatment

The patient had surgical site infection after dorsal slit and also as there was purulent discharge on pressing the swelling, some component of periurethral abscess was present. He was initially given intravenous antibiotics (see above) and oral anti-inflammatory drugs (Aceclofenac+Serratiopeptidase) for 7 days. Two weeks following this, the patient underwent open surgical removal of the calculi (figure 5) and dorsal buccal mucosal graft urethroplasty of the proximal penile urethra over a 16F Foley catheter. Postoperative course was uneventful. The patient was discharged with the Foley catheter on the fourth postoperative day.

Figure 5.

(A) The urethra after removal of calculus. (B) The removed urethral calculus.

Outcome and follow-up

The catheter was removed after 3 weeks and after catheter removal the patient voided well with a maximal flow of 25 mL/s on uroflowmetry. At 3 months’ follow-up, the patient is asymptomatic.

Discussion

Urolithiasis is a major part of urologic practice. Patients with UC form a small proportion (0.3%–2%) of the spectrum of urinary tract calculi. UC is more common in males. The incidence is higher in children especially in low/middle-income countries where malnutrition is common leading to formation of vesicle calculus that subsequently migrates in the urethra.¹ Urethral calculi may be primary or secondary. Secondary UC migrates from the upper tracts into the urethra whereas primary UC forms when there is stasis of urine such as in cases with urethral diverticulum or stricture. In the present case, it was a primary UC due to urethral stricture disease. The upper urinary tracts and the urinary bladder did not show any evidence of calculus disease on US. In the present case, the aetiology of urethral stricture was idiopathic as there was no other inciting cause for it. UC is more common in posterior urethra than anterior urethra.²

The clinical symptoms of UC vary depending on the stone location. The patient may have dysuria, haematuria, rectal pain and suprapubic pain, or may present with acute retention of urine. The UC may be palpable on deep palpation. Sometimes due to the surrounding inflammation the UC may not be evidently palpable. Due to the varied presentation it is sometimes difficult to make the diagnosis clinically. As was the case in our patient, where an initial diagnosis of periurethral abscess was made. A case of UC was reported in a female where initially a tumour was suspected.³

Most of the times, UC is readily apparent on a plain X-ray pelvis. Some UC may be radiolucent and thus not diagnosed on plain X-ray film. Many a times they are diagnosed while doing cystoscopy.⁴ The other useful diagnostic modality is US. A CT scan is rarely required for diagnosing a UC.¹

There are many options for management of UC ranging from non-invasive, minimally invasive (cystoscopic) and open surgical removal. The management of UC is guided by size and location. Smaller stones have a higher chance of spontaneous expulsion. Instillation of 2% lidocaine jelly may aid in spontaneous expulsion. Stones in the posterior urethra may be manipulated into the urinary bladder followed by cystolithopaxy. When one fails to push the stone back into the urinary bladder in situ fragmentation by holmium laser is also a feasible option if the facility is available.⁵ US lithotripsy for removal of UC in urethral diverticulum has also been described.⁶ UC in anterior urethra may be grasped and removed by a forceps, but this should preferably be done by an experienced urologist, so as to avoid injuring the urethra. Open surgery is the last resort but larger UC usually requires open removal.^{1 3}

Learning points.

• Urethral calculus may be associated with concomitant stricture urethra or urethral diverticulum.

• A plain X-ray pelvis is a useful diagnostic test as most of the urethral calculus is radio-opaque.

• Although urethral calculus is most of the times easy to diagnose, it may sometimes be missed as it has variety of symptomatic presentations and may be found incidentally while investigating for other urethral diseases.

• Most urethral calculus may be removed with minimal invasive methods or may expel spontaneously.

• Open surgery is usually the last resort and is required for larger calculi.