What are the causes of anterior abdominal wall pain syndromes?

From the Guidelines

Anterior abdominal wall pain syndromes are primarily caused by abdominal cutaneous nerve entrapment syndrome (ACNES), rectus sheath hematoma, myofascial pain syndrome, and slipping rib syndrome, which can be diagnosed and managed through a combination of physical examination, imaging, and targeted treatments. The most common causes of anterior abdominal wall pain syndromes include:

• Abdominal cutaneous nerve entrapment syndrome (ACNES)
• Rectus sheath hematoma
• Myofascial pain syndrome
• Slipping rib syndrome These conditions often present with sharp, localized pain that worsens with movement, and can be misdiagnosed as visceral problems 1. A careful physical examination revealing pain that changes with abdominal muscle contraction or specific trigger points can help differentiate these conditions from internal organ pathology 1. Treatment typically involves local anesthetic injections, oral NSAIDs, physical therapy, and trigger point injections, depending on the specific condition 1. Imaging, such as ultrasound or CT, may be necessary to confirm the diagnosis in unclear cases 1. It is essential to note that the evaluation of patients with nonspecific abdominal pain, with or without fever, requires a comprehensive approach, including imaging and laboratory tests, to determine the underlying cause of the pain 1. In the absence of clear evidence of internal organ pathology, a diagnosis of anterior abdominal wall pain syndrome should be considered, and treatment should be tailored to the specific condition 1. Overall, a thorough physical examination, imaging, and targeted treatments are essential for the diagnosis and management of anterior abdominal wall pain syndromes, with the goal of improving morbidity, mortality, and quality of life for patients with these conditions.

From the Research

Causes of Anterior Abdominal Wall Pain Syndromes

The causes of anterior abdominal wall pain syndromes can be attributed to several factors, including:

• Nerve entrapment at the lateral border of the rectus abdominis muscle, which is a common cause of abdominal anterior cutaneous nerve entrapment syndrome (ACNES) 2, 3
• Entrapment of cutaneous branches of thoracoabdominal nerves at the lateral border of the rectus abdominis muscle, leading to chronic abdominal pain 2
• Entrapment of nerves at the medial border of the rectus muscle, which can also cause ACNES 3
• Other abdominal wall conditions or disorders that affect the nerves to the abdominal wall, which can be overlooked as a source of abdominal pain 4

Characteristics of ACNES

ACNES is characterized by:

• Chronic abdominal pain caused by entrapment of cutaneous branches of thoracoabdominal nerves 2
• Estimated incidence of 10-30% of the adult population 2, 3
• Often refractory, chronic pain that can be severe 5
• Difficulty in making a diagnosis, which can be facilitated by the use of ultrasound and specific diagnostic criteria 3, 5

Management of ACNES

The management of ACNES can involve:

• Conservative treatment with pain medication, botulinum toxin, or lidocaine injections 2
• Surgical management, such as anterior neurectomy, which can be effective in resolving pain 2
• Ultrasound-guided injections, such as perforator-guided drug injection, which can provide safe and accurate administration of drugs 6
• Other therapeutic strategies, including trigger point injections, chemical neurolysis, and radiofrequency ablation 5