What is the likely diagnosis for the persistent arousal-like sensation after fistulotomy and how should it be managed?

Post-Fistulotomy Neuropathic Hypersensitivity: Diagnosis and Management

Most Likely Diagnosis

This presentation is most consistent with pudendal nerve irritation or neuropathy secondary to surgical trauma from the fistulotomy, manifesting as persistent dysesthetic sensations misinterpreted by the nervous system as arousal-like feelings. 1, 2

The constant "hyper feeling" you describe represents neuropathic pain with dysesthesia—abnormal nerve sensations that can include burning, tingling, or inappropriate sensory interpretations in the perineal region. 2, 3 This occurs when the pudendal nerve or its terminal branches are irritated, stretched, or damaged during fistula surgery, leading to aberrant nerve signaling. 4, 5

Immediate Symptomatic Management

Start topical 0.3% nifedipine with 1.5% lidocaine ointment applied three times daily for at least 6 weeks to reduce sphincter hypertonicity and provide local anesthetic relief. 1 Pain relief typically begins after 14 days of consistent use. 1

• Add oral analgesics such as paracetamol or ibuprofen for severe episodes. 1
• Consider neuropathic pain medications (gabapentin or pregabalin) if topical therapy provides insufficient relief, as these target the aberrant nerve signaling causing your symptoms. 2, 5
• Apply topical metronidazole cream if there are concerns about poor wound healing or low-grade infection, which improved healing rates from 56% to 86% in one study. 1

Critical Diagnostic Evaluation Required

You must undergo anorectal manometry to quantify sphincter dysfunction and establish baseline pressures, as this will guide all subsequent treatment decisions. 1

• Endoanal ultrasound is essential to assess for active inflammation, fluid collections, or structural sphincter defects that could be perpetuating nerve irritation. 1
• Evaluation for active proctitis or rectal inflammation is mandatory, as this would contraindicate any further surgical intervention. 1, 6
• MRI of the pelvis should be requested to rule out any tumoral pathology, anatomical anomaly, or occult abscess that could be compressing neural structures. 7, 2

Understanding the Underlying Mechanism

The pudendal nerve controls sensation to the glans penis, scrotum, perineum, and anus, and is also responsible for erectile function and sphincter control. 3 When this nerve is irritated or compressed—whether from surgical trauma, scar tissue formation, or inflammation—it can produce burning pain, dysesthesias, and abnormal sensory perceptions including inappropriate arousal-like sensations. 2, 3, 4

The "constant arousal" feeling represents pudendal nerve dysesthesia—the nerve is sending aberrant signals that your brain misinterprets as sexual arousal, when in reality it is neuropathic irritation. 2, 5 This is a recognized manifestation of pudendal neuropathy. 4, 5

What NOT to Do: Critical Pitfalls

Never undergo repeat sphincterotomy or cutting setons, which result in 57% incontinence rates and would catastrophically worsen your sphincter function and nerve damage. 1, 6

• Avoid aggressive dilation, which causes permanent sphincter injury in 10% of patients. 1, 6
• Do not ignore these symptoms hoping they will resolve spontaneously—early intervention prevents chronic pain syndrome development. 2, 5

Confirming Pudendal Neuralgia

If symptoms persist despite initial management, you should be evaluated using the Nantes criteria for pudendal neuralgia, which include: 2, 3, 5

• Pain in the anatomical territory of the pudendal nerve (perineum, genitals, anus)
• Pain that is worse with sitting and relieved by standing or lying down
• Pain that does not wake you from sleep (though you mention sleep disruption, which may indicate more severe involvement)
• No objective sensory loss on examination
• Pain relieved by diagnostic pudendal nerve block with local anesthetic

A positive response to pudendal nerve block with local anesthetic is diagnostic and therapeutic, providing both confirmation of the diagnosis and temporary relief. 2, 3, 5

Long-Term Management Strategy

If conservative management fails after 6-8 weeks, referral to a pelvic pain specialist or pain management physician experienced in pudendal neuralgia is essential. 1, 2

Treatment escalation follows this algorithm:

1. First-line multimodal treatment: Topical agents, neuropathic pain medications (gabapentin/pregabalin), pelvic floor physical therapy, and behavioral modifications. 2, 5, 8

2. Second-line interventional treatment: Pudendal nerve blocks with local anesthetic and corticosteroid, which provide pain improvement in 70-80% of properly selected patients. 2, 3, 8

3. Third-line surgical treatment: Pudendal nerve decompression-neurolysis surgery should be considered if there is a positive response to nerve blocks, with healing rates of 50-60% and pain improvement in 70-80% of cases. 2, 3, 8 This is only appropriate after failure of conservative measures and in specialized centers. 2

4. Alternative interventions: Radiofrequency ablation, cryotherapy, and botulinum toxin injections have insufficient evidence and should only be considered in specialized centers within therapeutic protocols. 2, 8

Adjunctive Measures

Maintain a high-fiber diet (25-30g daily) with adequate water intake to prevent constipation and reduce anal trauma during bowel movements. 1

• Perform warm sitz baths 2-3 times daily to promote sphincter relaxation and healing. 1
• Avoid prolonged sitting—use a cushion with a central cutout to reduce perineal pressure. 2, 5
• Continue topical calcium channel blockers prophylactically if symptoms persist beyond initial treatment. 1

Setting Realistic Expectations

Complete restoration of pre-surgical sensation may not be achievable given the extent of nerve irritation, but significant improvement is possible with appropriate treatment. 1, 8 The goal is to reduce neuropathic signaling, promote nerve healing, and maximize your quality of life. 1

Most patients with pudendal neuropathy experience meaningful pain reduction with multimodal treatment, though the timeline varies from weeks to months. 8 Early intervention prevents progression to chronic centralized pain, which is much more difficult to treat. 2, 4