2017/10/01 by Diego Hidalgo, Diego F. Hidalgo, Jennifer Phemister +4 · 1 citation
Biochemistry, Genetics and Molecular Biology · Medicine · #Myofascial pain diagnosis and treatment #Medical research and treatments #Biomedical and Chemical Research
paper · doi:10.14309/00000434-201710001-01403
Chronic Abdominal Wall Pain (CAWP) is a condition where the pain originates from the abdominal wall itself (somatic pain) rather than from a viscera underneath the wall (visceral pain). The most common cause of CAWP is anterior cutaneous nerve entrapment syndrome. The Nerve Entrapment Syndrome was first described by Metha and Ranger in 1971(1). The cutaneous branches of sensory nerves (T7 -T12) go through the posterior rectus sheath, passing through a fibrous ring. Normally, fat in the neurovascular bundle permits the nerve to slide unimpeded within the fibrous ring (2). Entrapment of the nerve can be caused by intra or extra abdominal pressure or localized scarring. \We report the case of a 52-year-old male presented with right upper quadrant pain. He has a past medical history of diabetes mellitus type II, coronary artery disease, and chronic diarrhea. The pain appeared 4 days ago, localized on the right upper quadrant, 8/10, sharp, radiated to the lower sternum. It improved with positioning and got worse with palpation. Physical exam unremarkable, except for the pain described above. An abdominal US did not reveal gallbladder thickening or stones. The patient was sent home and an outpatient HIDA scan was ordered which showed high suspicious for partial common bile duct obstruction. He was sent to the Emergency Room again. A second physical exam showed the same picture than the previous one 2 days ago, with an additional finding of Carnett sign. Due to the abnormal HIDA scan, an MRCP was done which came back normal. A solution of xylocaine with triamcinolone was injected at the site of the pain after the procedure, relieving the pain immediately and confirming the diagnosis. Anterior cutaneous nerve entrapment syndrome is the most common cause of chronic abdominal wall pain. It is diagnosed mainly with physical exam (Carnett sign), where the leg-raising test is performed and the abdominal pain tenderness should remain the same or get worse to be considered positive. Having a positive Carnett sign means that the abdominal pain get worse when the abdominal wall get more tense, suggesting a somatic type of pain. A negative Carnett sign suggests an intra abdominal cause of pain (visceral). Any clinician should be suspicious of this entity as it is an easy diagnosis and saves a lot of unnecessary expenses. A positive response after an anesthetic injection is consistent with the diagnosis of nerve entrapment and therapeutic at the same time.Figure: Normal MRCP. No CBD dilation. No gallstones or sludge found.Figure: When localizing own pain, patient points left index finger, for example, to T-10 opening. Clinician reaches in from lateral side to confirm location is a neuromuscular foramen.