Urology
A 76 year old man presents to the Emergency Department complaining of scrotal pain over the last 12 hours. He has a past medical history of type 2 diabetes and rheumatoid arthritis. On examination he is febrile and tachycardic. You note a grossly erythematous scrotum and perineum, both are tender to touch. What is the most likely diagnosis?
Answer:
In the early stages of the condition, patients may simply present with severe perineal/scrotal pain, out of proportion to clinical signs, which may include erythema, swelling and pyrexia. Clinical features are often non-specific until significant deterioration, most commonly seen in those who are “not quite right” for a simple cellulitis.Fournier’s Gangrene
Urology
Last Updated: 12th February 2021
Fournier’s gangrene is a form of necrotising fasciitis that affects the perineum. Whilst rare, it is a urological emergency with a mortality rate of 20-40%.
Pathophysiology
Fournier’s gangrene can be a monomicrobial or a polymicrobial infection, with causative organisms including Group A streptococcus, C. Perfringens, and E. Coli.
There is a predictable pathway for the spread of Fournier’s Gangrene based on scrotal anatomy. Anatomic barriers to the spread of infection include the dartos fascia of the penis and scrotum, Colles fascia of the perineum, and Scarpa fascia of the anterior abdominal wall. As a result, the testes and epididymis are commonly not affected by the fasciitis.
Risk factors
Diabetes mellitus, excess alcohol, smoking, poor nutritional state, steroid use, haematological malignancies, immunosuppression and recent trauma to the region (allowing the protective outer layers of the perineum to be breached) are all known risk factors.
Clinical features
In the early stages of the condition, patients may simply present with severe perineal/scrotal pain, out of proportion to clinical signs, which may include erythema, swelling and pyrexia. Clinical features are often non-specific until significant deterioration, most commonly seen in those who are “not quite right” for a simple cellulitis.
As the condition progresses, crepitus, skin necrosis, and haemorrhagic bullae may begin to develop. Sensory loss of the overlying skin may also occur.
Patients will rapidly deteriorate and become significantly unwell with sepsis.
Differential diagnosis
The differential in the setting of acute scrotal pain includes:
- Epididymo-orchitis
- Testicular torsion
- Testicular trauma
- Scrotal cellulitis/abscess
Investigations
Diagnosis is largely clinical. Any suspected cases should be taken for immediate surgical exploration.
Ensure routine bloods, including blood cultures, are taken.
Imaging can be useful if the diagnosis is not clear, to determine the extent of disease or to detect the underlying cause:
- Plain radiograph
- Radiolucent soft-tissue gas may be seen in the region overlying the scrotum or perineum.
- Subcutaneous emphysema may extend from the scrotum and perineum to the inguinal regions, anterior abdominal wall, and thighs.
- Ultrasound
- Thickened scrotal wall
- Echogenic gas foci in the scrotum (pathognomonic)
- Testes and epididymides spared
- Peritesticular fluid
- CT
- Soft tissue stranding, fascial thickening
- Soft tissue gas
- Extent of disease may be demarcated
- Cause of infection may be apparent (e.g. perianal abscess, fistula)
Management
The definitive management is urgent surgical debridement. The earlier this is performed, the better the outcomes.
The surgical debridement usually encompasses partial or total orchiectomy, depending of the size of expansion of the process, with the wound usually left open.
Patients should be started on broad-spectrum antibiotics and transferred to a high-dependency setting. Antibiotics can be tailored accordingly, depending on culture sensitivities. Fluid resuscitation and close monitoring is essential in such cases, due to the potential rapid deterioration that can occur.
Often further surgical debridement is required; secondary closure with skin grafts can be a long process, aiming to re-cover the scrotum. Post-operative outcomes vary, depending on disease extent and tissue involvement.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
