Abdominal cutaneous nerve entrapment syndrome (ACNES) is one of the now recognised causes of chronic abdominal pain. It remains an overwhelmingly underdiagnosed condition and consequently not readily managed or recognised. It is generally characterised by patients presenting with a severe, often refractory, chronic abdominal pain just lateral (next to) the midline. Often the pain can be pinpointed to a specific location on the abdomen. It is theorised that the cutaneous branches of the lower thoracoabdominal intercostal nerves are ‘trapped’ at the lateral border of the rectus abdominis muscle. The pain experienced will be in the distribution of one or more dermatomes as shown in the figure below.
Symptoms of ACNES
Pain is experienced just next to the middle of the abdomen either on the right or the left side from the lower border of the ribs down to just above the groin. The pain can radiate around to the back, up and down the abdominal wall and is not related to any gastrointestinal symptoms such as diarrhoea, constipation or other altered bowel habit with or without weight loss. The prevalence of the syndrome ranges between 15% and 30% depending on the definition and the diagnostic criteria that is used. In adolescents, it is reported to be diagnosed in one out of eight cases of chronic abdominal pain. In the emergency department, the prevalence of ACNES in the patients presenting with acute abdominal pain has been reported to be a mere 2% of cases as usually there is the presence of a serious acute pathology in such patients.
Clinically when examining a patient, pain at the point of tenderness can be palpated when the abdomen is soft and if the patient is asked to ‘sit up’ and hold this position i.e tensing the abdominal muscles; if this makes the pain worse then this is a positive Carnett’s test and more in keeping with ACNES, if not then the test is negative.
It is important to exclude an underlying abdominal or gastrointestinal condition before the diagnosis of ACNES can be made.
ACNES is caused by the entrapment of the cutaneous end branches of the intercostal nerve in the muscular foramen as they pass through the rectus abdominis, which probably leads to ischemic neuropathy. Etiology is unclear, but there seems to be a causative relation with any kind of abdominal surgery, pregnancy and sometimes trauma. However, in more than half of the patients there is a sudden onset of pain, without any specific event.
At Alimran Medical Center, we may recommend any of the following treatments
- Trigger point injections
- Epidural steroid injections
- Electrical stimulation
- Short and long wave
- Laser therapy
- Ultrasonic therapy
- Magnatic therapy