ACNES syndrome, exploring the abdominal wall as source of abdominal pain

Abstract

Abdominal wall pain, specifically ACNES syndrome (Anterior Cutaneous Nerve Entrapment Syndrome), is part of the differential diagnosis of chronic abdominal pain. This syndrome is frequently overlooked and therefore underdiagnosed.

Objectives: To describe the clinical and evolutionary characteristics of patients diagnosed with ACNES and to draw attention to this pathology.

Patients and Method: A retrospective descriptive study was carried out in a reference center, between October 2016 and July 2021, in patients under 17 years of age, diagnosed with ACNES, who met at least two of four of the following findings: Carnett’s sign, Pinch test, dysesthesia at the point of maximum pain, improvement after infiltration of local anesthetic, having ruled out visceral or functional abdominal pathology. Epidemiological variables, symptoms, physical examination, complementary tests, treatment, and evolution data were collected. Descriptive statistics were used.

Results: 20 patients diagnosed with ACNES, 75% women, median age 12.85 years. The abdominal examination revealed Carnett’s sign in 95%, Pinch test sign in 65%, and dysesthesia in 90% of patients. 65% reported pseudovisceral symptoms. 7 patients were overweight or obese. The most frequent location (50%) was the right iliac fossa, at T10-T11 level. One patient reported spontaneous improvement; 7 improved with oral analgesia; 9 patients were referred to the pain unit, of which 5 attended, and improved with anesthetic infiltration with bupivacaine-triamcinolone. The remaining 4 were lost to follow-up.

Conclusion: ACNES should be considered in patients with chronic pain. A combination of typical findings in medical history and physical examination allows its diagnosis, therefore, avoiding unnecessary complementary tests. A step-up treatment strategy should be applied, beginning with oral analgesia, followed by anesthetic infiltration, and, finally, anterior neurectomy