(239) - Chronic abdominal pain due to anterior cutaneous nerve entrapment syndrome, a diagnosis almost missed

Abstract

Chronic abdominal wall pain due to anterior cutaneous nerve entrapment syndrome is frequently confused with visceral pain which often leads to extensive testing before the correct diagnosis. In this condition, the cutaneous branches of lower thoraco abdominal intercostals nerves are entrapped at the lateral border of rectus abdominis muscle resulting in severe, often refractory chronic pain. This syndrome is often under diagnosed and under treated. It is very well illustrated by case of 16-year-old male who was seen at our Pain clinic for long standing localized right sided upper abdominal pain which was brought on by activity. He had extensive work up performed by Gastroenterologist and Sports Medicine involving multiple Xrays, CT abdomen, endoscopy, colonoscopy, HIDA scan and performance evaluations without a conclusive diagnosis for over a year. Based on the presentation we suspected anterior cutaneous nerve entrapment syndrome and hence right rectus abdominus trigger point injections were attempted. Point of maximal pain was elicited by active jogging on treadmill and ultrasound visualization to inject in and around the muscle belly. It provided significant improvement in his symptoms but was relatively short lived. Plan was then made for cryoablation with which patient was able to achieve more prolonged relief. Hence, significant pain relief after trigger point injection is considered to establish the diagnosis. The current treatment options include ultrasound guided injections, radiofrequency ablation, cryoablation, anterior neurectomy which can provide adequate relief for the patient. To summarize, the diagnostic challenge posed by this condition can be addressed by having higher degree of suspicion on the part of physicians. An early diagnosis can prevent central sensitization, avoid plethora of investigations and successful intervention can be therefore be made.