Anterior cutaneous nerve entrapment syndrome with pain present only during Carnett’s sign testing: a case report
Tanizaki and Takemura BMC Res Notes
Anterior cutaneous nerve entrapment syndrome with pain present only during Carnett's sign testing: a case report
Ryutaro Tanizaki 0 2
Yousuke Takemura 0 1
0 Department of Community Medicine, Nabari, Mie University Graduate School of Medicine , Tsu, Mie , Japan
1 Department of Family Medicine, Mie University School of Medicine and Graduate School of Medicine , Tsu, Mie , Japan
2 General Medicine, Nabari City Hospital , Nabari, Mie , Japan
Background: The 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 presentation: A 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. Conclusions: It 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.
ACNES; Carnett's sign; Lidocaine; Abdominal wall pain; Physical examination
Background
Anterior cutaneous nerve entrapment syndrome
(ACNES) is a condition in which chronic or intermittent
abdominal wall pain is caused by irritation of the
cutaneous nerve roots passing through the abdominal fascia [
1
].
The incidence of ACNES is still unclear, and may account
for 10–30% of patients with chronic abdominal pain
in gastroenterological practice [
2, 3
] and 2% of patients
presenting with acute abdominal pain in the emergency
department [4]. When ACNES is suspected, cutaneous
injection of an anesthetic agent into the painful area is
used for both diagnosis and treatment [
5
]; if pain
continues after anesthetic injection, surgery might be required
[
6, 7
].
Carnett’s sign is a clinical examination finding that is
useful for confirming whether pain originates from the
abdominal viscera or from the abdominal wall.
During testing for Carnett’s sign, the investigator identifies
the point of maximal abdominal pain by deeply
palpating with a finger; the patient is then asked to tense the
abdominal muscles while the fingertip is released,
followed again by deep palpation. If both stages of the test
are painful, the source of the pain is the abdominal wall.
In contrast, pain originating from the abdominal organs
is associated with just a painful first stage [8]. Although
Carnett’s sign is considered useful for diagnosing ACNES
[
9
], identification of ACNES is often challenging due to
poor recognition and a lack of widely accepted standard
guidelines regarding laboratory and imaging tests for the
diagnosis of ACNES. Furthermore, as the degree of pain
can vary from mild to severe, if a patient presented with
severe pain, ACNES might be misdiagnosed as visceral
disease. Herein, we describe a case of ACNES in which
the patient presented with no abdominal pain during
regular palpation, but experienced abdominal pain when
Carnett’s sign was examined.
Case presentation
A 77-year-old Japanese man presented with chronic
mild lower abdominal pain for the past 3 years. The pain
had occurred spontaneously and was exacerbated on an
empty stomach and during feelings of stress, without
any other accompanying symptoms. Despite the chronic
abdominal pain, the patient was able to mountain climb
as a hobby. The results of abdominal computed
tomography and upper gastrointestinal endoscopy done at a local
hospital were normal. Rebamipide and lansoprazole had
been administered for abdominal pain by a local doctor,
but the symptoms did not resolve. The patient had a past
medical history of active pulmonary tuberculosis 2 years
previously, and polypectomy of a colonic polyp 1 year
previously.
Physical examination revealed that the patient’s
body temperature was 36.4 °C, blood pressure was
128/60 mmHg, pulse rate was 66 beats/min,
respiratory rate was 15/min, and oxygen saturation was 95%
(room air). There were no remarkable abnormalities of
the head, eyes, ears, nose, mouth, chest, and extremities.
There was no tenderness of the abdominal region
during palpation, and swab testing, alcohol testing, and skin
pinching all produced negative results. Carnett’s sign was
not examined at that time. All laboratory investigations
showed values within normal range. Thoracic magnetic
resona (...truncated)