🩺 Acute Scrotal Pain

Acute scrotal pain is a common urological emergency that requires rapid assessment to differentiate between conditions requiring immediate surgery and those managed medically. It occurs when there is sudden pain, swelling, or tenderness within the scrotum. In the UK, the priority is the exclusion of testicular torsion, as delay in diagnosis leads to testicular ischaemia and permanent loss of the gonad. Management often involves a "low threshold" for surgical exploration.

The speed of onset is the most important factor: torsion typically presents with sudden, severe pain, often waking the patient from sleep. Ask about associated nausea and vomiting, which are common in torsion. Inquire about urinary symptoms (dysuria, frequency) and urethral discharge, which point toward epididymo-orchitis. Ask about recent trauma or heavy lifting. Establish sexual history and risk of STIs. In older men, check for symptoms of bladder outlet obstruction or recent urological instrumentation.

The patient should be examined standing and supine. Observe for scrotal swelling, erythema, and the "blue dot sign" (suggestive of torsion of the hydatid of Morgagni). In torsion, the testis is often high-riding with a horizontal lie. Palpation will reveal exquisite tenderness; try to localise this to the epididymis (suggesting epididymitis) or the body of the testis. Assess for a cremasteric reflex (stroking the inner thigh). Perform an abdominal exam to exclude referred pain from renal stones or appendicitis, and a digital rectal exam if prostatitis is suspected.

The most critical differential is testicular torsion. Others include epididymo-orchitis (often STI-related in men <35, or enteric organism-related in men >35), torsion of the testicular appendage (hydatid of Morgagni), and scrotal trauma/haematoma. Less acute causes include an incarcerated inguinal hernia, hydrocele, or varicocele. Rarely, a testicular tumour can present with acute pain due to intratumoural haemorrhage. Referred pain from a ureteric stone must also be considered.

Sudden onset of severe pain; nausea and vomiting; horizontal lie of the testis; absent cremasteric reflex; systemic sepsis or skin necrosis (Fournier's gangrene); pain not settling with simple analgesia.

If testicular torsion is suspected clinically, no investigations should delay surgical exploration. If the diagnosis is unclear and the index of suspicion for torsion is low, a Scrotal Ultrasound with Doppler can assess blood flow (though it has false negatives). Mid-stream urine (MSU) and urethral swabs (for NAAT) should be taken if infection is suspected. Inflammatory markers (CRP) may be raised in epididymitis but are less helpful in the hyperacute phase of torsion. Blood cultures are needed if the patient is septic (Fournier's).

Testicular torsion is a surgical emergency; 'time is muscle,' and any delay in theatre for imaging can lead to orchidectomy. The 'Prehn's sign' (elevation of the scrotum relieving pain in epididymitis) is notoriously unreliable and should not be used to rule out torsion. The cremasteric reflex is usually absent in torsion but can be present in early or intermittent cases. Fournier's gangrene is a rare but life-threatening necrotising fasciitis of the perineum, often seen in diabetic or immunocompromised patients.

Fits within the Urology and Emergency Medicine MLA themes. Emphasises the "surgical sieve" approach to acute pain. Knowledge of the window for salvage in torsion (ideally <6 hours) is essential. Students must know that surgical exploration is indicated if torsion cannot be confidently excluded; "when in doubt, wash out" (explore).