ACNES is a common cause of abdominal pain often overlooked and misdiagnosed as intra-abdominal disorders.
Misdiagnosis can lead to unnecessary consultations, tests, and surgeries, with significant financial costs.
Example: Greenbaum (1999) estimated $914 per patient; Thompson et al. (2001) noted $6,727 on average per patient.
Frequently misdiagnosed as psychiatric conditions like anxiety, depression, or hysteria.
Pathophysiology of ACNES
Peripheral nerve entrapment occurs at sites where nerves change direction, enter tunnels, or pass over bands, causing irritation and swelling.
Muscle contraction may compress or traction on nerves, causing further injury.
Entrapment leads to localized swelling, possibly compromising nerve circulation.
Anatomy Pertinent to ACNES
Thoracoabdominal nerves terminate as cutaneous nerves anchored at six points: spinal cord, posterior, lateral, anterior branches, accessory branches, and skin.
Most common entrapment site: lateral border of the rectus abdominis muscle.
Nerve vascular bundle can herniate through fibrous ring, causing compression and ischemia.
Maneuvers increasing abdominal pressure can exacerbate the condition.
Diagnosing ACNES
Clinical Presentation
Symptoms: localized, dull or burning pain, sometimes with a sharp component.
Acute pain often occurs at night but doesn’t prevent patients from working the next day.
Pain radiates with movement; lying down may help or worsen it.
Common misdiagnoses: ovarian disorders in women, hernia or ulcer in men.
Carnett’s sign: differentiates between abdominal wall pain and intra-abdominal pain.
Physical Examination
Key: accurately identify the tender spot by palpation.
Carnett’s sign to distinguish source of pain.
Pinch test and electromyographic studies used to confirm diagnosis.
Injection of local anesthetic can help confirm diagnosis.
Recommended Treatment for ACNES
Local anesthetic injection into the muscular channel can relieve pain.
Technique is critical; needle should not be inserted too deeply.
Sequential injections may be needed for persistent cases.
Other treatments include ice application, elastic bandage, or heat.
Corticosteroids may be used, but caution is advised due to potential pain and atrophy.
Summary and Conclusions
Pain in the abdominal wall is often misdiagnosed as intra-abdominal pain.
ACNES is commonly caused by nerve entrapment at the lateral border of the rectus muscle.
Diagnosis and treatment involve local anesthetic injections.
Early recognition and treatment can prevent unnecessary tests and surgeries.
Clinicians should monitor ACNES patients closely and evaluate for visceral diseases if no improvement.
Practice Tips:
Use local anesthetic injections for diagnosis/treatment.
Encourage precise location of pain from patients.
Consider nerve entrapment in cases of unexplained abdominal wall pain.