Testicular Abscess

Testicular abscess is a collection of pus within the testis, usually a complication of epididymo orchitis.

It occurs in about 3 to 4% of patients with epididymo orchitis, and is more frequent with diabetes, immunosuppression, delayed treatment and bladder outlet obstruction.

It carries a high rate of testicular loss. Orchidectomy is required in a large share of cases.

Pathophysiology. Inflammation of the testis leads to focal necrosis and liquefaction. Swelling inside the tunica albuginea compromises venous outflow, and ischaemia promotes necrosis.

Organisms:

• Escherichia coli, Proteus, Klebsiella, Pseudomonas and Enterococcus.
• Staphylococcus aureus, including meticillin resistant strains, and Streptococcus.
• Salmonella, Brucella, Mycobacterium tuberculosis and fungi.
• Burkholderia pseudomallei in endemic areas.

The abscess may rupture through the scrotal skin or extend to give a pyocele or necrotising infection.

Severe scrotal pain, fever, rigors and swelling, with a tender swollen testis and sometimes fluctuance, erythema and a skin sinus. Failure of epididymo orchitis to improve after 48 to 72 hours of antibiotics is the common clue. Sepsis may be present.

Rapid spread of erythema, skin crepitus, dusky skin or systemic collapse suggests necrotising infection of the scrotum (Fournier gangrene), which needs immediate surgery.

• Full blood count, C-reactive protein, creatinine, glucose and HbA1c, blood cultures, urine culture and sexually transmitted infection nucleic acid tests. HIV test.
• Doppler ultrasound: a complex, thick walled, hypoechoic collection within the testis with peripheral hyperaemia and absent central flow. Compare with the other testis.
• Contrast CT or MRI when the extent is uncertain or necrotising infection is suspected.
• Pus or aspirate (at surgery or by image directed aspiration): Gram stain, aerobic and anaerobic culture, and acid fast bacilli stain, culture and nucleic acid testing.
• Tumour markers (AFP, beta-hCG, lactate dehydrogenase) when a tumour with necrosis is a possibility.

Differential diagnosis.

• Testicular tumour with necrosis or haemorrhage
• Testicular infarction
• Haematoma or haematocele
• Epididymo orchitis without abscess
• Pyocele
• Granulomatous or tuberculous orchitis
• Infected hydrocele
• Torsion

• Admit and resuscitate: intravenous fluids, oxygen if needed, analgesia (morphine 2 to 5 mg intravenously, titrated, with paracetamol 1 g every 6 hours, maximum 4 g daily).
• Antibiotics once cultures are taken: ceftriaxone 2 g intravenously once daily plus metronidazole 500 mg intravenously every 8 hours. Add vancomycin 15 mg/kg intravenously every 12 hours (adjusted to eGFR and trough levels of 10 to 20 mg/L) when meticillin resistant Staphylococcus aureus is likely or the patient is in septic shock. Adjust to culture. Avoid gentamicin when kidney function is impaired.
• Duration: intravenous treatment until afebrile for at least 48 hours and the collection is drained, then oral treatment directed by cultures to complete 2 to 4 weeks in total.
• Drainage: scrotal exploration with incision and drainage of the abscess, debridement of necrotic parenchyma, and irrigation, with a drain. Image directed aspiration is used for a small collection (under about 2 cm) in a stable patient who is improving.
• Orchidectomy for a necrotic testis, extensive abscess, failed drainage, or uncontrolled sepsis.
• Necrotising infection: emergency debridement, broad spectrum antibiotics (piperacillin-tazobactam 4.5 g intravenously every 8 hours with vancomycin, adjusted to renal function, or adjusted to culture), and intensive care.
• Diabetes: intravenous insulin to keep glucose at 6 to 10 mmol/L during sepsis.
• Tuberculosis: a 6-month antituberculous regimen. Brucellosis: doxycycline 100 mg twice daily plus rifampicin 600 to 900 mg once daily for 6 weeks.
• Counselling about loss of the testis, fertility and testosterone, and a testicular prosthesis later.

Monitoring. Daily review in hospital with inflammatory markers, ultrasound at 2 to 4 weeks, and again at 3 months. A persistent mass over 6 weeks needs tumour markers and exploration or biopsy. Semen analysis and morning testosterone at 3 to 6 months.

Referral and escalation. Urgent urology referral for every suspected case. Immediate theatre for necrotising infection, septic shock or no improvement in 48 hours.