Diagnostics of pudendal neuralgia: Nantes criteria.
Neuropathy of the pudendal nerve is a condition that requires diagnostic assessment consisting of several stages. It lacks specific signs, so before making a diagnosis, it is necessary to ensure that all characteristic symptoms are present and to exclude other etiologies of pelvic pain.
In 2006, a multidisciplinary working group in the French city of Nantes identified five main criteria that should characterize the course of the disease. If any of the specified phenomena are not observed, it is necessary to postpone the treatment of pudendal neuropathy and continue diagnostic work, focusing on other possible scenarios.
With this pathology, it is difficult to immediately make a correct diagnosis, and inattention on the part of the doctor leads to very serious errors. This is especially true for diseases that do not have specific clinical signs, which would allow one to confidently determine: this patient has a damaged pudendal nerve, and they need surgery. Unfortunately, diagnosing sexual neuropathy requires a lot of attention and additional research.
The patient describes painful sensations resembling signs of compression:
— It feels like someone, sorry, doctor, is biting or stinging my scrotum. And it doesn't completely go away, although it gets easier in some positions.
— Is the pain localized exclusively in the scrotal area?
— I wouldn't say so. Perhaps more from the coccyx to it or slightly above. In general, it hurts almost everywhere. It's difficult to go to the bathroom because of this.
So far, everything aligns — the symptoms resemble those of pudendal neuralgia. During the examination, the patient demonstrated a normal reaction to palpation of the affected area — no decrease in sensitivity was observed. It seems worth prescribing additional tests to confirm the diagnosis, primarily considering attempting a diagnostic blockade under ultrasound control.
— Tell me, how do you sleep? Does the pain interfere with your sleep, waking you up at night?
— Yes, I often wake up in the middle of the night from pain and then can't find a comfortable position to fall asleep again...
However! It seems the blockade may not be necessary after all. The diagnosis of "pudendal neuropathy" is likely if all five Nantes criteria are present, but there is a discrepancy here. Neuralgic pain in pudendal nerve involvement typically does not interfere with sleep — moreover, many patients admit that they cannot wait for the night when they feel worse. Because the pain diminishes during sleep and is usually less pronounced afterward.
I ask new questions, observe the patient's posture. He sits relaxed on the chair, not fidgeting, not favoring one buttock. Perhaps the most important question:
-How long can you sit on the chair?
-As long as needed. The pain can flare up when I sit, stand, lie down... It doesn't matter. It eases with a hot shower.
And here we have excluding signs. It seems we need to look for other causes, such as myofascial pelvic pain syndrome.
— I'm afraid we still have to determine the cause of your condition. New examinations are necessary...
Nantes criteria
This is a list of five signs that a doctor pays attention to primarily:
1. There is pain (burning, tingling, sensation of a foreign body, etc.) in the area innervated by the pudendal nerve, from the anus through the entire perineum to the external genitalia.
Pain is present (burning, stabbing, sensation of a foreign body, etc.) in the area innervated by the pudendal nerve — from the anus, across the entire perineum, to the external genital organs.
3.The pain does not cause sleep disturbances or nighttime awakenings. If the patient complains of waking up due to pain, further diagnostics should be performed to identify other causes, ruling out pudendal neuralgia.
4.There are no significant disturbances in tactile sensitivity. If such disturbances are observed in the examined area, the cause should be sought in damage to nerves of a different origin.
5.Diagnostic pudendal nerve block causes a noticeable improvement in the patient's condition.
The nerve block procedure requires no special preparation and involves injecting a local anesthetic (lidocaine or a newer agent from the same group) into the tissues near the pudendal nerve. If the hypothesis is correct and the pain is indeed caused by entrapment or inflammation of the pudendal nerve, the patient will experience relief for a period ranging from 4 to 36 hours.
Additional Symptoms
Additional criteria, while not mandatory, are commonly present in most patients with pudendal nerve neuralgia. The pain:
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Is neuropathic in nature and can be described as stabbing, burning, shooting, sometimes accompanied by slight numbness;
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May radiate to the buttock area when sitting;
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More often manifests on one side;
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Intensifies by the end of the day (less pronounced upon waking in the morning);
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Can be triggered by defecation, especially if straining is involved.
Additionally, pain may occur on the inner thigh, in the suprapubic region, or after sexual intercourse. Sometimes pudendal nerve involvement is associated with frequent urination and erectile dysfunction. However, these are not mandatory — the main diagnostic criteria remain five in total.
Symptoms Excluding the Diagnosis
There are also several signs that help exclude possible pudendal nerve entrapment. Another cause of the pain should be sought if the pain is localized only in the lower abdominal, coccygeal, or gluteal regions, or if it has a paroxysmal (episodic) rather than constant nature. Skin itching in the affected area may occur with neuralgia but should not be the primary or sole symptom of the condition.
How is the final diagnosis made?
There are no specific clinical signs that definitively diagnose “pudendal nerve neuropathy.” No single test alone can prove the presence of the condition. For a sufficiently accurate diagnosis, a thorough examination of symptoms combined with several diagnostic methods is required.
The final diagnosis of pudendal neuralgia is made based on the presence of several or all of the following criteria:
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Typical symptoms of pudendal neuropathy;
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Pain triggered by pressure along the nerve’s path;
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A positive response to pudendal nerve block;
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Exclusion of other possible pathologies.
Required diagnostic examinations include:
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Ultrasound of the pudendal nerves, sacrospinous ligaments, and all pelvic muscles;
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Doppler ultrasound of the pudendal arteries to assess blood flow velocity;
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Electroneuromyography (ENMG) of the pudendal nerves using the Saint Mark’s electrode.
A specialist experienced in nerve imaging can locate the exact site of the nerve damage and make the final diagnosis.
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