Abdominal wall pain syndrome.

1. Abdominal wall pain:
Professor Dr.Mohamed Alshekhani
MBChB-CABM,FRCP,EBGH.

2. AWP:Introduction:
 Frequently overlooked or mistaken for visceral pain.
 Often leads to extensive/unnecessary testing before final
diagnosis.
 There are various types, according to the component affected.
 The most common is anterior cutaneous nerves entrapment
syndrome (ACNES).
 An accurate diagnosis can be made by careful history ,PE&
excluding causes outside the abdominal cavity.
 The diagnosis of AWP can be confirmed by response to trigger
point injection (TPI) of local anesthetic.
 Once the diagnosis is made, treatment options include:
conservative measures, TPI& in refractory cases, surgery.

3. Epidemiology:
 Common
 The prevalence in Primary care practice:
 3.6% for patients with a previous diagnosis of functional abd pain.
 30% of chronic abd pain cases with negative findings on prior
diagnostic evaluation
 10% of all gastroenterology referrals.
 43% of cases referred to chronic pain clinic by gastroenterologists.

4. Epidemiology:
 Common patient characteristics of chronic AWP:
 Often obese.
 Women *4 greater likelihood .
 Prior abd surgery
 Pregnancy
 Sports-related injuries
 Age 30 - 50 years.

5. Pathophyiology:
 Pathophysiology depends on which component affected:
 The most common cause is ACNES, from entrapment of an
anterior cutaneous branch of one of the thoracic nerves, T7 - T12,
as it passes through rectus abdominis muscle.
 Pathologic processes affect one or more of abd wall components,
as HZ, DM radiculopathy, rectus sheath hematoma, Spigelian or
incisional hernias, endometriosis,cancer&nerve entrapments.
 These nerves make 90 angles just before entering a fibrous ring
through the posterior rectus sheath& immediately after passing
through the anterior sheath&a discrete fat pad or plug in the
neurovascular bundle allows unimpeded sliding within the fibrous
ring.

7. Pathophyiology:
 Distinct mechanisms of entrapment can occur:
 1. Enlargement of the abd can cause herniation through the
fibrous ring& subsequent nerve trapping with ischemia& pain,
supported by occurring more commonly in obese, pregnants&
ascites.
 2. Entrapment mechanism within a scar:
 T12 is often entrapped after appendectomy, hysterectomy, or
suprapubic transverse herniorrhaphy.
 T8 or T9 can become entrapped after cholecystectomy.
 Other processes affecting the nerve, including HZ, tumors, or
traumatic radiculitis, might cause similar pain by diff
mechanisms.

8. Clinical features:
 Certain features suggest AWPS.
 Initially be sharp, followed by a dull persistent ache,often chronic,
nagging& nonprogressive, range from mild to excruciating,
continuous to intermittent, with complete remissions lasting for
months or years.
 Location:anywhere in the abdomen, with the right side
predominating, some patients might have more than one site of
pain ,rarely, may present with dull pain over a broader area.

9. Clinical features:
 Often positional & exacerbated by sitting or lying on the affected
side, standing, walking, stretching, coughing, laughing, or
sneezing, all tensing of the abd musculature.
 Food ingestion will lead to gastric distention &increase in intraabd
pressure, reflexive abdominal wall contraction &potentially
increase AWP postprandially
 Contraction of the abd muscles with defecation can increase AWP
associated with bowel movements, making these features
unhelpful in differentiating AWP from visceral etiologies.
 An alternative reason for concomitant visceral symptoms in
patients with AWP is the segmental relationship between affected
intercostal nerves & internal organs via splanchnic chains.

10. Clinical features:
 A common feature(poiting sign): the pain may be so sharply
localized& most tender over a small area of the abd wall (<2 cm in
diameter), which the patient indicates by pointing with fingertip,
almost always indicates that the pain originates in the abd wall;
visceral pain cannot be so precisely localized because of the wide
spinal cord overlap of the viscerosensory representation, but when
AWP is severe, the pain may radiate diffusely.
 AWP can coexist with IBS& other functional GI disorders.

12. Diagnosis:Hover sign
 A discrete localization of pain that allows the patient to finger
point to a small area of maximum tenderness; “hover sign” & the
patient guards the area from light touch, sometimes by seizing the
examiner’s hand.

13. Diagnosis: Carnett sign
 Carnett test is performed by palpating the abdomen of the supine
patient in the usual way to elicit the area of tenderness.
 When the tender spot is localized, the patient is asked to contract
the abd muscles by raising the head & trunk or lower extremities
off the examining table while the examiner continues to hold
pressure.
 Once the muscles are tensed, the patient is asked if the pain has
altered.
 +ve Carnett sign is stable or worsening pain at the point of
maximal tenderness during contraction of the abd wall muscules.
 If the cause of symptoms is intra-abdominal, the tensed muscles
protect the viscera & the tenderness diminishes.

14. Diagnosis: Carnett sign
 Carnett sign strongly supports the diagnosis of AWP.
 Pain relief after injection of a local anesthetic (ie, TPI) is
considered confirmation of the diagnosis of AWP, successful
injection after elicitation of the Carnett sign (to diagnose AWP) is
“one of the most cost effective procedures in gastroenterology.”
 Although the Carnett test alone is 78% sensitive & 88% specific for
diagnosing AWP, the presence of AWP does not always rule out an
existing intra-abdominal source of pain.
 An intra-abdominal source of pain present in 3-9% patients with
AWP diagnosed by the presence of a Carnett sign, with the most
common cause being appendicitis, specially if warning signs such
as unintentional weight loss were present.
 So Carnett sign should be interpreted in context& clinician should
remain alert to warning symptoms or signs.

16. Diagnosis:Pinch test
 Pinch test is an additional PE maneuver that is sensitive in
detecting AWP due to ACNES.
 The skin&subcutaneous tissue of the area with somatosensory
disturbance are pinched between the index finger&the thumb.
 In the area of abd tendernesspinching the abd skin is
disproportionately painful compared to the contralateral side in
most patients with AWP.
 A positive pinch test result is a highly sensitive (>90%) finding of
AWP due to ACNES.

17. Differential Diagnosis:
 The DD of AWP includes entities with pain of seemingly abd wall
origin not successfully treated with TPI, include:
 Abdominal wall hernias.
 Endometriosis.
 Thoracic nerve radiculopathy.
 Lower rib pain syndromes.
 Psychogenic abdominal pain.

18. Treatment : reassurance
 Patient education about diagnosis &treatment is fundamental to
provides reassurance, mitigates anxiety &reduces the patient’s use
of health care resources (eg, emergency department visits&
diagnostic imaging).
 Patients with mild-moderate AWP may choose to forgo treatment
after an explanation of the diagnosis.

19. Treatment : TPI
 If patients desire treatment, multiple options including:
 1. Lidocaine patch application.
 2.Local inj with local anesthetic with or without corticosteroids.
 3.Chemical neurolysis.
 4.Surgical neurectomy.

20. Treatment:TPI
 Injection of local anesthetic alone provides immediate relief in 50-
77% higher if combined with CS& with U/S -guided injection.
 U/S-guided TPI for AWP provided significant, long-term relief of
AWP in 30% of participants, with 60% having at least some
improvement.
 The selection of the site for injection was identified in some
patients by the aid of electrical stimulation eliciting paresthesia in
the painful area.
 For patients with persistent or recurrent pain after a single
injection, a second injection into the trigger point leads to lasting
relief in a small percentage.
 Somatization was the only negative predictor of treatment
response.

21. Treatment:Phenol neurolysis
 Chemical neurolysis yielded only a 54% rate of permanent& total
relief of pain, not substantially better than TPI with anesthetic /
corticosteroid,so it is difficult to recommend this treatment.

22. Treatment:surgery
 Surgical treatment with neurectomy is available for medically
intractable AWP& nerve bundle at the site of maximal pain is
exposed& a small segment is excised,considered only in patients
who have debilitating pain with only temporary relief after
repeated injection treatments &other causes of abd pain excluded.
 The primary success rate of neurectomy over the long term is
reported to be high at 70%& a second operation may be highly
successful for those with recurrent pain.

25. CME1:
 1. Which is the most common location of abdominal wall pain?
 a. Right upper quadrant
 b. Right lower quadrant
 c. Left upper quadrant
 d. Left lower quadrant
 e. Umbilicus

26. CME1:
 1. Which is the most common location of abdominal wall pain?
 a. Right upper quadrant
 b. Right lower quadrant
 c. Left upper quadrant
 d. Left lower quadrant
 e. Umbilicus

27. CME2:
 2. Which one of the following is the initial step in the evaluation of
abdominal wall pain?
 a. Abdominal ultrasound
 b. Computed tomography of abdomen
 c. Trigger point injection
 d. Lidocaine patch application
 e. A detailed history and performing a physical examination

28. CME2:
 2. Which one of the following is the initial step in the evaluation of
abdominal wall pain?
 a. Abdominal ultrasound
 b. Computed tomography of abdomen
 c. Trigger point injection
 d. Lidocaine patch application
 e. A detailed history and performing a physical examination

29. CME3:
 3. Which one of the following is the most common cause of abdominal
wall pain?
 a. Anterior cutaneous nerve entrapment
 b. Epigastric hernia
 c. Umbilical hernia
 d. Endometriosis
 e. Spigelian hernia

30. CME3:
 3. Which one of the following is the most common cause of abdominal
wall pain?
 a. Anterior cutaneous nerve entrapment
 b. Epigastric hernia
 c. Umbilical hernia
 d. Endometriosis
 e. Spigelian hernia

31. CME4:
 4. Which one of the following physical examination findings, when
positive, is most helpful for distinguishing abdominal wall pain from
visceral causes?
 a. Hover sign
 b. Carnett sign
 c. Obturator sign
 d. Psoas sign
 e. Rovsing sign

32. CME4:
 4. Which one of the following physical examination findings, when
positive, is most helpful for distinguishing abdominal wall pain from
visceral causes?
 a. Hover sign
 b. Carnett sign
 c. Obturator sign
 d. Psoas sign
 e. Rovsing sign

33. CME5:
 5. Which of the following conditions is the most common cause of a
false positive Carnett sign?
 a. Peptic ulcer disease
 b. Endometriosis
 c. Cholecystitis
 d. Appendicitis
 e. Diverticulitis

34. CME5:
 5. Which of the following conditions is the most common cause of a
false positive Carnett sign?
 a. Peptic ulcer disease
 b. Endometriosis
 c. Cholecystitis
 d. Appendicitis
 e. Diverticulitis

35. CME6:
 4. Which set of the following physical examination findings, when
positive, is most helpful for distinguishing abdominal wall pain from
visceral causes?
 a. Hover sign &sister josef sign.
 b. Carnett sign & pinch test.
 c. Obturator sign &Cullen sign.
 d. Psoas sign and grey turner sign.
 e. Rovsing sign and transmitted thril sign.

36. CME6:
 4. Which set of the following physical examination findings, when
positive, is most helpful for distinguishing abdominal wall pain from
visceral causes?
 a. Hover sign &sister josef sign.
 b. Carnett sign & pinch test.
 c. Obturator sign &Cullen sign.
 d. Psoas sign and grey turner sign.
 e. Rovsing sign and transmitted thril sign.

37. CME7:
 4. The following are included in the DD of AWBS except:
 Inguinal hernias.
 Endometriosis.
 Thoracic nerve radiculopathy.
 Lower rib pain syndromes.
 Psychogenic abdominal pain.

38. CME7:
 4. The following are included in the DD of AWBS except:
 Inguinal hernias.
 Endometriosis.
 Thoracic nerve radiculopathy.
 Lower rib pain syndromes.
 Psychogenic abdominal pain.

39. CME8:
 4. The following are treatment options for AWBS except:
 A.Local xylocaine TPI.
 B.Local Xylocaine and steroid TPI.
 C.Neurectomy.
 D.Phenol neuro ablation.
 E.Reassurance.

40. CME8:
 4. The following are treatment options for AWBS except:
 Local xylocaine TPI.
 Local Xylocaine and steroid TPI.
 Neurectomy.
 Phenol neuro ablation.
 Reassurance.