What are the potential causes and treatment options for a patient experiencing a pulsating feeling in the perineum, considering factors such as age, medical history, and lifestyle?

Pulsating Feeling in the Perineum

A pulsating sensation in the perineum most commonly represents either normal vascular pulsations, chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), or pelvic floor muscle dysfunction, and requires immediate exclusion of priapism if accompanied by penile erection, followed by systematic evaluation for infectious, neurological, and musculoskeletal causes. 1

Immediate Red Flag Assessment

First, determine if this is a urological emergency:

• Ask specifically about concurrent penile erection lasting >4 hours - this constitutes acute ischemic priapism requiring immediate corporal blood gas analysis and intervention within hours to prevent permanent erectile dysfunction 2
• Examine for fever, scrotal/perineal skin changes, necrosis, crepitus, or systemic toxicity - these signs indicate Fournier's gangrene, a surgical emergency with high mortality if delayed 1
• Check for rigid, painful corpora cavernosa with spared glans and corpus spongiosum - this physical finding confirms ischemic priapism 2

Critical History Elements

Obtain these specific details to narrow the differential:

• Pain quality and radiation: Ask if there is pain at the tip of the penis radiating to the perineum, which is the hallmark presentation of CP/CPPS 1
• Urinary symptoms: Specifically inquire about urgency, holding maneuvers, interrupted stream, weak flow, or need for abdominal pressure to void - these suggest CP/CPPS or pelvic floor dysfunction 1
• Bowel patterns: Ask about constipation and fecal incontinence, as these commonly coexist with pelvic floor disorders and may be the primary driver 1
• Trauma history: Perineal straddle injury can cause non-ischemic priapism with pulsatile sensations from arteriovenous fistula formation 2
• Medication and drug use: Directly question about erectile dysfunction treatments (intracavernosal injections, PDE5 inhibitors) and recreational drugs (cocaine, marijuana), as these are frequently underreported but commonly cause priapism 2, 1

Physical Examination Priorities

Perform a focused examination of genitalia, perineum, and abdomen:

• Palpate for pulsatile masses - a true pulsatile mass may represent an abdominal aortic aneurysm with transmitted pulsations, though this is rare in the perineum 2
• Assess perineal descent - have the patient perform a Valsalva maneuver and observe for excessive perineal descent (>2-3 cm), which correlates with pelvic floor neuropathy 3
• Check anal tone and sensation - impaired perineal sensation and reduced anal tone suggest cauda equina syndrome if accompanied by bilateral leg symptoms 2

Diagnostic Workup Algorithm

Order tests based on clinical presentation:

If Priapism is Suspected:

• Obtain corporal blood gas immediately - PO2 <30 mmHg, PCO2 >60 mmHg, and pH <7.25 confirm ischemic priapism 2
• Consider penile duplex Doppler ultrasound if the diagnosis between ischemic and non-ischemic priapism is unclear - scan both the penile shaft and perineum in the erect state looking for turbulent flow from arteriovenous fistula 2

If Infection is Suspected:

• Obtain midstream urine culture to identify bacterial pathogens 1
• Order blood cultures and complete blood count if fever or systemic signs are present 1
• Perform nucleic acid amplification testing on first-void urine for Chlamydia trachomatis and Mycoplasma species 1

If Neurological Cause is Suspected:

• Urgent MRI of lumbosacral spine if bilateral leg symptoms, saddle anesthesia, or urinary retention are present to exclude cauda equina syndrome 2

Treatment Based on Etiology

For Acute Ischemic Priapism:

• Initiate intracavernosal phenylephrine injection (100-500 mcg every 3-5 minutes) with or without aspiration/irrigation as first-line therapy 2
• Proceed to distal shunting procedures if phenylephrine fails after multiple attempts 2

For Non-Ischemic Priapism:

• Recommend 4 weeks of observation unless the patient is severely bothered, as many arteriovenous fistulas close spontaneously 2
• Offer percutaneous fistula embolization as first-line therapy if persistent after observation and the fistula is visible on duplex ultrasound 2

For CP/CPPS:

• Start empiric fluoroquinolone therapy (levofloxacin 500 mg daily or ciprofloxacin 500 mg twice daily) for minimum 4 weeks if infectious etiology cannot be excluded 1
• Refer to pelvic floor physical therapist for assessment and treatment of nonrelaxing pelvic floor muscles 1
• Treat constipation first if present, as pelvic floor symptoms are difficult to resolve without addressing this 1

Common Pitfalls

• Do not delay evaluation for Fournier's gangrene - any perineal symptoms with systemic signs require immediate surgical consultation, as delay is fatal 1
• Do not rely solely on systemic treatment for ischemic priapism in patients with sickle cell disease or hematologic disorders - intracavernosal treatment must be administered concurrently 2
• Do not assume normal vascular pulsations without excluding pathology - the sensation described as "cell phone-like buzzing" has been reported as a novel presentation of CP/CPPS 4
• Do not overlook age-related changes - anal sensation and pudendal nerve terminal motor latency worsen with age and straining, which may contribute to symptoms 3