Anterior cutaneous nerve entrapment syndrome with pain present only during Carnett’s sign testing: a case report

Abstract

BackgroundThe identification of anterior cutaneous nerve entrapment syndrome is often challenging, due to no widely accepted standard guidelines regarding laboratory and imaging tests for the diagnosis of ACNES.Case presentationA 77-year-old Japanese man presented with mild lower abdominal pain that had been present for the past 3 years. Physical examination revealed no abdominal pain during palpation, with normal laboratory and imaging testing; therefore, conservative therapy was initiated. However, the abdominal pain continued. Re-examination 16 days later revealed three tender points in accordance with intercostal nerves Th10, Th11, and Th12, with the pain occurring only during Carnett’s sign testing. A cutaneous injection of 1% lidocaine was administered, and the abdominal pain was resolved about 30 min later. Based on these results, anterior cutaneous nerve entrapment syndrome was diagnosed.ConclusionsIt is sometimes hard to diagnose anterior cutaneous nerve entrapment syndrome without testing for Carnett’s sign. If patients present with chronic abdominal pain, clinicians should test for Carnett’s sign even if no pain is elicited during regular abdominal palpation.

Difficult differentiation of a somatic symptom disorder from anterior cutaneous nerve entrapment syndrome (ACNES): a case report

“…Owing to its rarity and difficulty to diagnose, ACNES often presents as a chronic pain problem, with 30 to 35% of patients reporting pain starting more than 1 year before the initial presentation [13]. To reproduce the pain associated with anterior cutaneous nerve entrapment, Carnett’s sign should be evaluated [13, 14]. The role of this sign is to differentiate somatic pain from visceral abdominal pain.…”

Protracted diagnosis of ACNES: a costly exercise

“…Other causes include previous surgery with scarring, and ascites, obesity or pregnancy leading to increased intra-abdominal pressure and external compression [ 2 , 7 ]. An important clinical feature was a positive Carnett’s sign as well as persistent point tenderness [ 5 , 6 ].…”

“…This not-so-rare disorder is presented in order to spare future patients a protracted series of costly investigations. Diagnostic delays lead to excessive tests, invasive procedures and imaging studies, which cause psychological, physical and economic issues for patients [ 6 ]. The most damaging concern for this patient was whether her pain was actually believed by consulting physicians [ 4 ].…”

“…As this was unremarkable, she then had a liver ultrasound in January 2018, which showed mild fatty liver. Subsequent gastroenterology referral diagnosed hypothyroidism and stress and she was offered laxatives and anti-depressants [ 6 ].…”

“…The patient is able to pinpoint the pain with one finger at the exact site at which the nerve is compressed and this is an important feature of the syndrome. Another diagnostic feature is a positive Carnett’s sign, which is useful for confirming whether pain originates from abdominal viscera or from the abdominal wall [ 5 , 6 ]. The incidence of ACNES is thought to be 10–30% of patients with chronic abdominal wall pain [ 7 ].…”