腹部皮神經壓迫症候群（ACNES）：常被忽視的腹痛原因

摘要

腹部皮神經壓迫症候群（ACNES）會引起慢性腹痛，該病症的痛楚來自於在腹直肌位置被壓迫的皮層神經。然而，ACNES常常被忽視, 導致患者不明不白地長期承受慢性腹痛及過度的醫學檢查甚至不必要的腹部手術。ACNES估計佔慢性腹痛病例的10-30％。臨床上，ACNES通常表現為局部的、鈍的或火燒般的痛楚，並在收緊腹部肌肉時加劇。治療方式包括口服藥物和物理治療以改善痛楚和姿勢，以及在神經受壓點注射局部麻醉藥或類固醇等介入性療法。對於頑固的ACNES，可以考慮脈衝射頻治療或神經燒融術。若大眾對ACNES加強認識，很多慢性腹痛的患者便可得到更快，更識切的治療。

導言

腹部皮神經壓迫症候群（ACNES）的特徵是慢性腹痛，這種痛楚來自於已經在腹部腹直肌處受壓。ACNES常常被忽視，導致患者不明不白地長期承受慢性腹痛及接受大量不必要的醫學檢查，甚至不必要的腹部手術。

流行病學

ACNES的流行率研究顯示出了變化，但估計其佔慢性腹痛病例的10-30％。Orphanet，一個歐洲的罕見疾病資料庫，報告說大約20％的慢性腹痛是由ACNES引起。

基本病理

ACNES涉及下胸腹部皮層神經分支、腹直肌和腹壁層和它的筋膜。胸腹神經在進入腹直肌鞘後，會急速轉向腹直肌，然後再到達皮膚。這種急速轉向使神經易於受壓。

臨床表現

ACNES通常表現為局部的、鈍的或火燒般的痛楚，間中患者會感覺到一股刺痛影響半邊腹部。當收緊腹部肌肉時，痛楚會加劇。這個情況經常使人誤會，痛楚來自腹部、盆腔或甚至心臟。患者經常接受大量診斷測試，例如CT掃描，但找不到任何病變。

治療

治療包括保守的方法，如口服藥物和物理治療以改善痛楚和姿勢。介入性療法，例如在神經受壓點注射，局部麻醉藥或類固醇，除了可幫助醫生確診病症外，還可以提供治療作用。對於頑固的ACNES，可以考慮選擇如重複注射或注射肉毒桿菌素(Botox)。脈衝射頻治療（pRF）是另一種選擇，利用脈衝電流來調節神經組織並減少疼痛信號。在嚴重的情況下，可以進行熱或化學神經切斷術，以破壞引起痛楚的神經。

結論

ACNES是常被忽視的慢性腹痛原因。加強對這病的認識可以使患者得到更早及更準確的治療。 

Abdominal Cutaneous Nerve Entrapment Syndrome (ACNES) is characterised by chronic pain resulting from the entrapment of cutaneous branches of the lower thoracoabdominal intercostal nerves at the rectus abdominis muscle. Common yet frequently unrecognised, ACNES can lead to long-term suffer of the patient and a cascade of unnecessary medical consultations, tests, and sometimes, unwarranted abdominal surgeries.

Studies show varying prevalence rates for ACNES, but it's estimated to account for 10-30% of chronic abdominal pain cases. Orphanet, a European rare disease database, reports that approximately 20% of chronic abdominal pain patients suffer from abdominal wall pain, primarily due to ACNES.

ACNES involves the cutaneous branches of the lower thoracoabdominal intercostal nerves, the rectus abdominis muscle, and abdominal wall layers, including the fascia. After entering rectus sheath, the thoracoabdominal nerve bending sharply toward the rectus abdominis before reaching the skin. This sharp bend predisposes the nerve to potential entrapment.

ACNES typically presents as localised, dull, or burning pain, often with a sharp, radiating component on one side of the abdomen. The pain intensifies with activities that tighten the abdominal muscles. Misinterpretation of the pain's origin is common, leading to assumptions that it emanates from the abdomen, pelvis, or even the heart. Patients frequently undergo extensive but inconclusive diagnostic tests like CT scans.

Treatment includes conservative approaches such as oral pain medicine and physiotherapy for pain management and posture improvement. Interventional therapies, such as nerve entrapment point infiltration with anaesthetics with or without corticosteroids offer both diagnostic and therapeutic benefits.For persistent ACNES, options like repeated injections or Botox addition to the injectate may be considered. Pulsed Radio-Frequency treatment (pRF) is another alternative, using pulsed electrical currents to modulate nerve tissue and reduce pain signals. In refractory cases, thermal or chemical neurotomy, which involves destroying the problematic nerve in the abdominal wall, may be pursued.

ACNES is a common but often neglected cause of chronic abdominal pain. Recognizing ACNES in the differential diagnosis of chronic abdominal pain is vital. Better understanding of its prevalence, anatomy, clinical presentation, and treatment options is key to improving diagnosis and management of this frequently overlooked condition.

資料由疼痛醫學專科醫生

李旭明醫生提供