Clinical Vignettes/Case Reports-Practice Management.

Abstract

Anterior cutaneous nerve entrapment syndrome (ACNES) is a common cause of chronic abdominal pain that often goes undiagnosed and thus undertreated. Here we present a case of a man who was investigated extensively for ‘acute abdomen' and was found to have ACNES. A 62 year old male patient with a past medical history of coronary artery disease and GERD presented to the emergency department with complaints of recurrent abdominal pain of two months duration requiring multiple ED visits. The pain was sharp in nature, located in the left lower quadrant and associated with nausea. The patient denied any association with food or bowel movements. He denied vomiting or any changes in bowel habits. The patient had a left inguinal hernia repair 3 months prior. Vital signs were within normal limits. On physical exam, he was tender to palpation in the left lower abdomen with a clear transition line in the mid abdomen. A focal point of maximum tenderness was appreciated 2 cm distal to the left of the umbilicus. A positive Carnett's sign was elicited. All other physical exam findings were unremarkable. Laboratory work up was within normal limits. A right upper quadrant ultrasound and multiple CT scans of the abdomen showed no acute findings. Gastroenterology were consulted and a triamcinolone plus lidocaine injection was given to the point of maximum tenderness with instantaneous resolution of symptoms. Anterior cutaneous nerve entrapment syndrome (ACNES) is a commonly under-diagnosed and under treated cause of severe abdominal pain. The lower thoracoabdominal nerve roots become entrapped often at the lateral border of the rectus abdominis muscle causing pain. It is believed that the patient's hernia repair surgery was the culprit behind his presentation. Patients typically have pain on palpation of one site at the lateral border of the rectus abdominis muscle and a positive Carnett's sign. A positive Carnett's sign is appreciated if the pain increases or remains the same with the examiner's finger on the point of maximum pain as the patient raises both legs. A positive sign indicates abdominal wall pain. A trigger point injection resolving the symptoms may then confirm the diagnosis. Therefore, with high index of suspicion, it would save not only the patient from multiple unnecessary hospital visits, but also decrease hospital spending on unnecessarily work up like CT scans, ultrasounds and laboratory testing.