NIV Congres

Introduction: Patients with chronic abdominal pain are frequently seen in the department of internal medicine. Anterior Cutaneous Nerve Entrapment Syndrome (ACNES) is rarely recognized as a source of chronic abdominal pain. We describe a patient with ACNES with good response to treatment.

Case report:  A 26-year old women was referred to the emergency room because of severe, but localized pain in the right lower abdominal quadrant. Her complaints had started several weeks prior to presentation, were of a persistent nature and prevented her from performing her work. She denied nausea or vomiting and was not pregnant. On physical examination Carnett’s test was positive (investigator localizes the point of maximum pain with index finger, while the pain is aggravated when the patient lifts her head). Laboratory findings and abdominal ultrasonography were normal. With a presumed diagnosis of ACNES, 10 ml of 1% lidocaine was injected at the point of maximum pain. After this injection pain completely disappeared after several minutes. The pain recurred after 48 hours, and lidocaine administration was repeated. After successfully repeating this intervention several times the patient was referred to the surgeon, who performed a limited anterior neurectomy. Postoperatively the patient was free of pain after 24 hours and has remained so for the next 6 months.

Discussion: Up to 30 percent of patients with chronic abdominal pain suffer from pain localized in the abdominal wall. Although these patients are seldom able to discriminate visceral from parietal pain themselves, simple testing enables making the distinction. ACNES is a pain syndrome thought to be the result of entrapment of cutaneous branches of an intercostal nerve at the level of the abdominal rectus muscle. Etiological factors are previous surgery and pregnancy. The gold standard for making the diagnosis is the injection of 10 ml of 1% lidocaine at the point of maximum pain, after which the pain must completely disappear. Treatment of choice is surgical intervention by performing neurectomy. An accelerated diagnostic pathway in patients with suspected abdominal wall pain may cut costs by reducing the number of unnecessary diagnostic investigations and averts frustration for both patient and doctor.

Conclusion: ACNES is an neglected source of chronic abdominal pain. This diagnosis should be considered in patients who have experienced prolonged negative evaluation. The syndrome is easy to diagnose and is simple to resolve with limited surgery.