ACNES: symptoms and treatment abdominal wall pain syndrome

ACNES stands for Anterior Cutaneous Nerve Entrapment Syndrome. The abbreviation ACNES sounds exotic, yet it is a common condition. When a patient is seen at the doctor’s office or emergency room with abdominal pain without other clinically significant symptoms, ACNES should be high on the list of likely diagnoses. Awareness of this specific abdominal pain syndrome is still very poor, even among doctors. What is ACNES, what are the symptoms of ACNES and how is it treated?

  • What is ACNES?
  • Synonyms
  • Who does it occur to?
  • Causes of ACNES
  • Compression of one end of a sensory nerve
  • Pregnancy and childbirth
  • Risk factors
  • Previous abdominal surgeries
  • Excessive exercise
  • Overweight
  • Pregnancy
  • Scar tissue
  • Abdominal exercises
  • Symptoms of ACNES
  • Phenomena
  • Stomach complaints
  • Additional complaints
  • Examination and diagnosis
  • Differential diagnosis of abdominal wall pain syndrome
  • LACNES
  • Appendicitis
  • IBS
  • Treatment of ACNES
  • Prognosis

ACNES / Source: Andrey Popov/Shutterstock.com

What is ACNES?

ACNES is an English abbreviation that stands for Anterior Cutaneous Nerve Entrapment Syndrome . This is an abdominal wall pain syndrome caused by compression of the skin branches of the anterior intercostal nerve endings, which pass through the abdominal muscles to the skin. These nerve branches provide the feeling of the abdominal skin. The pain experienced by ACNES can vary greatly from occasionally present in a relatively mild form to severe, unbearable pain. ACNES occur in all age groups and in both men and women.

Synonyms

Anterior Cutaneous Nerve Entrapment Syndrome (ACNES) is also known as ‘abdominal wall nerve entrapment syndrome’ or ‘Kómár syndrome’.

Who does it occur to?

This syndrome mainly occurs in young women, but also occurs in children, teenagers and the elderly.

Causes of ACNES

Compression of one end of a sensory nerve

In 2023, it is not yet clear what the precise cause is for the development of the ACNES pain syndrome. It is not clear why the end of the sensory nerve becomes pinched. However, there are circumstances that patients associate with the onset of pain. The Máxima Medical Center in Veldhoven has a separate website about ACNES and reports that in roughly half of the cases ACNES arises spontaneously, that is, without a known cause. A previous operation that caused the pain is reported in 20% of cases, although there may not be an anatomical connection with the course of the nerve. Examples of such operations are:

  • keyhole surgery
  • appendectomy operations
  • uterine operations
  • caesarean sections
  • gallbladder surgery

Pregnancy and childbirth

ACNES sometimes also develop during pregnancy or immediately after childbirth. In other people there is a relationship with sporting activities, such as abdominal exercises. All in all, (more) research is needed to determine the exact cause.

Risk factors

The risk factors associated with ACNES include:

Previous abdominal surgeries

If you have previously undergone abdominal surgery, such as an appendectomy, gallbladder removal or tummy tuck, you are at increased risk of developing ACNES.

Excessive exercise

Repetitive or intense exercise, especially in the abdominal area, can overstrain the nerves in the area. This increases your chance of getting ACNES.

Overweight

Overweight and especially obesity can put extra pressure on the nerves in the abdominal area. This also increases the risk of ACNES.

Pregnancy

During pregnancy, hormonal changes and the growth of the abdomen as your unborn child grows larger can put pressure on the nerves in the abdominal wall. This can contribute to the development of ACNES.

Scar tissue

Scar tissue can compress the nerves in the abdominal wall and lead to symptoms of ACNES. This may be the result of previous operations, injuries or inflammation in the abdominal area.

Abdominal exercises

Certain exercises that strain the abdominal muscles, such as sit-ups or crunches, can irritate the nerves in the abdominal wall and increase the risk of ACNES.

Symptoms of ACNES

Phenomena

Symptoms of ACNES can be acute or chronic. The pain is described as localized, that is, in one specific, easily identifiable spot – you can often point to the spot with one finger. This is a crucial information for making the diagnosis. When you move the finger one centimeter, the pain is perceived as less intense. In most cases the pain occurs below the navel level and therefore less often above the navel level.

Stomach complaints

Most people with ACNES have been complaining of abdominal complaints for some time, with the complaints worsening during daytime activities in which the abdominal muscles themselves are used to a greater or lesser extent. The pain reduces or even disappears completely when you lie in a calm, relaxed position. The pain is almost never present at night, except when you lie on your side, especially if it concerns the affected side.

Nausea / Source: Istock.com/CentralITAlliance

Additional complaints

Severe pain due to ACNES can give rise to symptoms suggestive of involvement of the abdominal organs, such as the stomach, appendix, gallbladder, ovaries, intestines, etc. This may inform a doctor who needs to make a diagnosis. wrong foot. The pain can make you feel quite nauseous, especially if ACNES manifests itself in the upper abdomen. If you eat less for this reason, you may lose weight unintentionally. You may also experience bloating and experience that your abdomen is larger or more swollen. People with ACNES who experience pain in the lower left abdomen may also have problems with bowel movements. ACNES in the lower abdomen can worsen with a full bladder. After you urinate, the complaints decrease again.

Examination and diagnosis

Once ACNES is considered based on the patient’s history, the diagnosis can be made through a thorough physical examination: increased pain under the physician’s palpating finger, when raising the legs straight, or when moving the chin toward the chest.

Differential diagnosis of abdominal wall pain syndrome

LACNES

In people with a suspected abdominal wall pain syndrome such as ACNES, nerve pain in the flank is often found. This concerns the lateral form of ACNES, namely: LACNES. This stands for ‘Lateral Cutaneous Nerve Entrapment Syndrome’. The pain with LACNES is always located in one specific spot on the flank and can be indicated with one finger.

Appendicitis

Acute (i.e. ‘sudden onset’) ACNES may resemble ‘acute abdominal pain’ and be associated with ‘acute appendicitis’.

IBS

According to the Máxima Medical Center, patients with chronic ACNES have often undergone all possible scans over time, sometimes even laparoscopic interventions or operations on the appendix or otherwise. They are often diagnosed with Irritable Bowel Syndrome (IBS), even though they do not have any problems with their intestines.

Treatment of ACNES

The pinched nerve can be treated with an anesthetic injection of corticosteroids. This is given exactly at the point of pain, where the nerve comes through the capsule of the abdominal muscle. According to the Máxima Medical Center, 15 to 20% of patients remain permanently pain-free after this single injection. If an anesthetic injection does not provide relief, you can try to influence the pain with so-called transcutaneous electrical nerve stimulation (TENS). TENS is a non-invasive procedure in which the nerves and muscles are stimulated with an electrical current. Another option used by pain specialists is to switch off the nerve branches with high-frequency current (Pulsed Radio Frequency, abbreviated as PRF). The affected nerve is treated with heat. The pain disappears, while the function of the nerve remains intact. In patients for whom all these measures do not help, it is suggested to perform surgery to release the pinched nerve endings. This is possible because it has no function for the abdominal muscles. After the operation, the pain often disappears and quality of life returns.

Prognosis

It often takes a long time before the correct diagnosis is made. Untreated ACNES can lead to functional disabilities and reduced quality of life. After the operation, the complaints often disappear and the quality of life returns.

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