ACNES · recognising it

Recognisable with one finger. And still missed for years.

The cruel thing about ACNES: no expensive scan is needed. The condition gives itself away through a few clear signs and a simple test from 1926. The problem is not that it cannot be found. The problem is that no one thinks of it.

Important first: this page helps you prepare the conversation with your doctor. It is not a diagnosis and you cannot diagnose ACNES in yourself. Abdominal pain can have many causes, and some are serious. Always keep investigating other causes in consultation with your doctor.
The signs

Five things typical of ACNES

Not every sign has to fit, but together they form a recognisable picture that clearly differs from organ pain.

👉 Pinpointed with one finger

The pain sits in one specific spot, usually on the edge or in the middle of the rectus abdominis muscle, and can be pointed to with one fingertip. More often below than above the navel.

🏃 Worse with exertion

The pain worsens when bending, getting up, coughing, vacuuming, exercising or walking, so with anything that tenses your abdominal muscles. With relaxation it eases.

🌙 Usually not at night

Strikingly: the pain is almost never present when you lie still at night, except sometimes when you lie on the affected side.

⚡ Sharp, burning or stabbing

The pain is often described as sharp, burning or stabbing, sometimes radiating to the side or the back, along the course of the skin nerve.

🧠 Changed sensation around the spot

Around the pain point, the feeling in the skin is often altered: oversensitive, or numb, or a different sense of cold. Pinching the skin there hurts disproportionately.

💡 The pattern matters

None of these points proves ACNES on its own. But pain you can point to with a finger, that worsens with tensing and eases with relaxation, belongs in the conversation about the abdominal wall, not only about the organs.

The 1926 test

Carnett's sign

Almost a hundred years old, simple, and still the most important way to tell abdominal wall pain from organ pain. A doctor can do it in a minute.

Step 1Find the spot

You lie on your back. The doctor uses one finger to find the point where the pain is most intense (the punctum maximum), usually along the edge of the rectus abdominis muscle.

Step 2Tense the muscle

The doctor asks you to lift your head or raise your straightened legs. This tenses the abdominal muscle while the finger keeps pressing on the pain point.

Step 3What happens?

Does the pain get worse or stay the same? Then the test is positive and points to the abdominal wall (ACNES). Does the pain actually decrease? Then the test is negative and points more towards an organ, because the tensed muscle then shields the organ.

Note: Carnett's test is an indication, not conclusive proof. The diagnosis is made by a doctor based on the whole story, the examination and sometimes a trial injection of anaesthetic at the pain point.
The crucial distinction

Abdominal wall or organ?

This is where it goes wrong in the consulting room. With abdominal pain, the organs are thought of first. ACNES only comes into view if you know what to look for.

Points to the abdominal wall

Fits ACNES

  • Pain that can be pointed to with one finger
  • Worse when tensing the abdominal muscle
  • Carnett's test positive
  • Altered skin sensation around the spot
  • Scans and scopes find nothing
Points to an organ

Fits visceral pain more

  • Pain diffuse, hard to pinpoint exactly
  • Decreases when tensing the abdominal muscle
  • Carnett's test negative
  • Linked to eating, bowel movements or urinating
  • Abnormalities visible on tests

Imaging such as ultrasound or MRI shows nothing in ACNES, and is mainly used to rule out other causes. That is exactly why ACNES so often gets stuck: "nothing found" is confused with "nothing wrong".

"Test after test came back negative. Only when someone pressed one finger on the right spot and had me lift my head did the penny drop."

Starting the conversation

What you can ask

You cannot give yourself a diagnosis, but you can put the right question on the table.

"Could this be abdominal wall pain rather than an organ? Could we do the Carnett test?"
"I can point to the maximum pain point with one finger, would you take a look at that?"
"The scans found nothing. What is left if we look at the abdominal wall?"
"Would a referral to a centre experienced with ACNES, such as SolviMáx, be worthwhile?"
Sources

Where this information comes from

Signs and symptoms of ACNES
Patient information from SolviMáx (Máxima MC): pain pinpointed with one finger, worse with exertion, almost never at night. See mmc.nl/solvimax (in Dutch).
Carnett's sign
ACNES guideline (Dutch guidelines database) and Stichting ACNES: the 1926 test to tell abdominal wall pain from organ pain. See richtlijnendatabase.nl and stichtingacnes.nl (in Dutch).
Abdominal wall versus organ, and the role of imaging
Case report in the Dutch Journal of Urology and the guideline: pinch test, sensory changes, and the fact that ultrasound and MRI show no abnormalities in ACNES. See the case report.

🏎 Need help right now?

New, severe or suddenly different abdominal pain should be assessed by a doctor: call your GP or out-of-hours service, and in case of immediate danger 112. Feeling low or having thoughts of suicide? In the Netherlands you can call or chat day and night with 113 via 0800-0113. Outside the Netherlands, contact your local emergency line.