Gut 1994; 35: 833-836 833 Chronic, non-visceral abdominal pain Gut: first published as 10.1136/gut.35.6.833 on 1 June 1994. Downloaded from D Sharpstone, D G Colin-Jones

When patients present with persistent or recur- TABLE I Generalfeatures ofmusculoskeletal abdominal wall rent abdominal pain it is all too easy to consider a pain visceral source and overlook other origins for Onset - often insidious but a history of injury - both minor and their symptoms. Patients with chronic abdomi- major - or repetitive trauma or unaccustomed physical activity. Pain - sharp component, often followed by a dull, persisting ache nal pain are often subjected to a variety of on the affected side, which may radiate widely both anteriorly procedures in an attempt to find a cause: simple and posteriorly in the distribution of a dermatome. Positional component - the pain may be aggravated or relieved by investigations may give way to more complex certain positions, changes in posture, lifting, coughing or and invasive ones in the pursuit of ever more sneezing. Modulatingfactors - relief by local application of heat, certain obscure diagnoses. Then failure to find a visceral positions, gentle pressure to support the area. cause for the pain may prompt the physician to apply a functional or psychosomatic label to the patient, with any treatment directed along those modifications to Carnett's original test include lines. An awareness, however, that abdominal tensing of the abdominal musculature by raising pain may have a non-visceral origin' 2 can fore- just the head and shoulders from the bed, or stall a fruitless search for intra-abdominal path- lifting both heels offthe couch. In our experience ology. A careful history and examination, and just enough movement ofthe head and shoulders being alert to the possibility of the symptoms to tense the muscles without flexing the trunk arising from outside the abdominal cavity, gives the optimum opportunity for keeping one's should permit an accurate diagnosis to be made, finger on the tender spot and eliciting any change appropriate treatment given, and an ever down- or persistence in abdominal wall tenderness. ward spiral of yet more negative investigations This test has been found to be sensitive and avoided. specific,45 in one study saving on average $900 per case on unnecessary investigations.4 Injec- tion of local anaesthetic into the tender area6 Abdominal wall gives reliefofpain and is of therapeutic as well as

The abdominal wall comprises the parietal diagnostic value. It affords excellent reassurance http://gut.bmj.com/ peritoneum, fat, aponeurosis, musculature, and to the patient when effective. skin, and derives its somatic nerve supply from the intercostal nerves T7 to T12. Patients have difficulty describing their pain clearly because MYOFASCIAL TRIGGER POINTS the accuracy of cutaneous sensation diminishes A common but often overlooked cause of considerably through the deeper tissues to the abdominal wall pain is a myofascial trigger

viscera. Referred pain is not yet fully under- point,7 previously called fibrositis, myalgia or on September 26, 2021 by guest. Protected copyright. stood, but the autonomic system provides muscular rheumatism. It is defined as a locus of visceral pain afferents through the sympathetic hyperirritability in a muscle or its connective system, which uses the same dorsal horn as the tissue, which is tender when compressed and if intercostal somatic nerves. Because of previous sufficiently hypersensitive gives rise to referred experience that most sensory impulses come pain and a muscular twitch. The precise histo- from the skin the brain is thought to interpret the logical nature of these trigger zones has never signal as originating superficially. The clinician been characterised although there are reports of needs to be aware not only of possible visceral fibrous tissue reactions and bands, with fatty sources of the pain, but also the more specific infiltration, and aggregates of nerve fibres. They symptoms and tests that point to an abdominal may result from mechanical overload or as wall origin (Tables I and II). sequelae of local inflammation. Myofascial trig- ger points are found in many areas of the body, especially around the scapulae and down the CARNETT S SIGN back,8 but can occur too in the anterior abdomi- In 1926 Carnett described3 a clinical test to aid in nal wall. An active trigger point is always tender the diagnosis of abdominal wall pain. The and found as a palpable band of muscle fibres, patient is examined supine and the site of which seems to prevent full lengthening of the maximum tenderness identified with the muscle fibres caused by associated spasm. Sharp examining finger. He is then asked to fold his arms across the chest and sit halfway up. If Queen Alexandra at the same elicits TABLE II Examination for musculoskeletal abdominal wall Hospital, Cosham, continued palpation point pain Portsmouth similar or increased pain the test is said to be D Sharpstone positive. Carnett's hypothesis was that ifthe pain Inspection for scars - a common source of such pain D G Colin-Jones tensed muscles Mild scoliosis from muscle spasm arose from visceral disease the Tenderness Correspondence to: so that the of Professor D G Colin-Jones, protected the underlying organs over site pain was while continued persists on tensing abdominal wall (Carnett's sign) Queen Alexandra Hospital, tenderness reduced; pain over vertebral body Cosham, Portsmouth, as Hampshire P06 3LY. implied abdominal wall pathology. Sitting up over the lateral spinous processes a level of fitness not Hyperaesthesia on light touch (hover sign) Accepted for publication Carnett describes requires Pain aggravated by lightly pinching of the skin of the affected area 15 October 1993 always attained by our patients and suggested 834 Sharpstonie, Colin-Jones

pressure may elicit a twitch response of the while curling up to flex the hip often gives some muscle band, accompanied by transient pain relief. There is hyperaesthesia and sometimes making the patient flinch and even jump. paraesthesiae felt in the distribution of the

Myofascial trigger points can be found in any nerve.'4 Hyperextension of the hip may aggra- Gut: first published as 10.1136/gut.35.6.833 on 1 June 1994. Downloaded from part of the abdominal musculature, especially in vate the pain. Tender spots should be sought and the rectus abdominis, from where pain may be the area injected for diagnostic and therapeutic referred throughout the abdomen and even purposes. Surgery is sometimes required to round into the back. Treatment is again by remove the nerve and give relief.' The hover injection oflocal anaesthetic, which usually gives sign may be helpful. Because of the hyper- rise to swift improvement, but this is not always aesthesia, if the hand hovers over the affected sustained and longer lasting treatment may be area the patient will tend to tense up and the required with a local injection of phenol, TENS lightest of touches will make them wince and try machine, or hot or cold applications over the to move the hand away. 6 Formal testing for light affected area. touch may also be helpful in identifying an area of hyperaesthesia.

NERVE ENTRAPMENT Nerve entrapment may occur anywhere along POSTOPERATIVE, INCISIONAL PAIN the path of the nerve fibre affected, from its Any abdominal incision, especially if lateral, can origin at the spinal cord, through its passage out cause local injury to nerves, with the subsequent through the tissues, to its termination over the formation ofa sensitive neuroma. When examin- anterior abdominal wall. Several specific nerve ing the patient it is vital to tense the abdominal entrapment syndromes have been described. wall, not only looking for a tender spot (Carnett's sign) but also for any evidence ofweakness of the wound, or incisional hernia, which may be Rectus abdominis nerve entrapment syndrome amenable to surgical repair. If no incisional Several authors have described a point of tender- hernia is found and a localised tender area found, ness just over the linea semilunaris of the rectus injection of local anaesthetic is helpful.'7 As sheath.9 '° Tensing the recti (as in Carnett's sign) already mentioned the ilioinguinal and makes the pain worse, and sometimes in thin hypogastric nerves are especially at risk from patients a dimple may be seen at the site of scars of appendicectomy, hernia repair, or tenderness. An anatominal explanation was hysterectomy. offered by Applegate," in which he explained

how the neurovascular bundle containing the http://gut.bmj.com/ anterior branches of the intercostal nerves turn SKELETAL PAIN rather sharply at the lateral border of the recti to Thoracic causefor abdominal pain run through fibrous tunnels in the muscle. He The anterior abdominal wall is innervated by the suggested that the trigger point is produced by intercostal nerves (T7-12), so the chest and herniation of the bundle with its protective fat thoracic spine may be a source of abdominal pad through gaps in the anterior rectus sheath. symptoms.

Clinically, however, it is often uncertain as to Painful rib syndrome'" (slipping rib syndrome, rib on September 26, 2021 by guest. Protected copyright. whether this is a true nerve entrapment or a tip syndrome) - This disorder is characterised by myofascial trigger point; distinguishing between pain in the lower costal margin8 associated with the two is not always possible. Again, an injec- increased mobility of the anterior costal carti- tion of local anaesthetic at the tender point is a lages of the 8th, 9th, 10, and 11th ribs. There are useful diagnostic and therapeutic procedure. fibrous attachments binding the lower costal cartilages to each other and it is thought that these bindings may be loosened by injury, per- Ilioinguinal and iliohypogastric nerve entrapments mitting greater mobility so that one rib can move The ilioinguinal nerve arises from T 12/LI nerve on another, producing a sharp pain followed by a roots. It runs across the posterior abdominal wall dull ache in that area, possibly from a brief nerve under the peritoneum and then becomes more entrapment of the intercostal nerve as it crosses superficial as it courses round the oblique muscle over that costal cartilage.'9 Some patients can layers. At a point 2-3 cm medial to the anterior associate the pain with particular movements. superior iliac spine, the nerve emerges super- There is diffuse tenderness over the lower costal ficially and runs down to supply the skin on the margin but one spot, usually the rib end, is upper medial aspect of the thigh, the root of the particularly tender.'8 Hooking the fingers under penis and anterior scrotum, or the mons pubis the loose rib and moving it up can reproduce the and labium majus. The iliohypogastric nerve pain in many patients.20 An explanation, and also arises from T12/LI and runs a similar course infiltration with local anaesthetic, are usually to the ilioinguinal, overlapping its area of inner- helpful although the tenderness and pain often vation, but including the hypogastrium.'2 These persist. 8 are nerves that are particularly likely to be Precordialcatchsyndrome - This not uncommon injured by surgery, such as appendicectomy, complaint particularly affects younger people hernia repair, and a Pfannensteil incision. 3 who experience an abrupt sharp, stabbing, chest Nerve entrapment is associated with a persistent pain, causing them to catch their breath."' The burning sensation in the iliac fossa, inguinal sharpness ofit may make the patient press on the region radiating into the groin, the top of the affected part of the chest wall and lean towards thigh, and the lower abdomen. It is made worse the affected side, wincing with pain. The pain by movement, including walking and straining; lasts seconds and then the subject can gradually Chronic, non-visceral abdoninlal pain8 835

straighten up and breathe normally again: a dull cycle. The importance of individual vertebral ache may follow for a time. It may affect either tenderness has also been highlighted by other side ofthe chest, but when it occurs low down on workers.26

the right side it may mimic biliary pain. A careful Gut: first published as 10.1136/gut.35.6.833 on 1 June 1994. Downloaded from history is needed - the sudden, sharp pain, catching of breath, and lasting such a short time HERNIAS is characteristic. There is rarely chest wall Most abdominal wall hernias are either visible or tenderness, and there is no diagnostic test. The palpable on clinical examination. The presence cause is unknown, but reassurance is usually of a lump with an expansile cough impulse is sufficient to relieve the patient's worries. sufficient to make the diagnosis. In a few Costochondritis (anterior chest wall syndrome) - patients, however, particularly the obese, the Chest pain from tenderness of the costal carti- diagnosis may be difficult. Ifsymptoms suggest a lages is well recorded, particularly as Tietze's hernia and there is a persisting discomfort in one syndrome (characterised by swelling and tender- area, which is tender to the examining finger, ness of the second and third left costosternal additional investigations such as ultrasound'7 cartilages). Tenderness of the costal cartilages and herniography28 are probably useful. The including the rib ends can be found anywhere technique of herniography entails injecting con- down the sternum, including the costal margin trast into the peritoneal cavity and the patient and the xiphisternum.2223 The patient complains postured to see if the contrast fills a hernial sac. of a dull ache and there is tenderness over the This is useful both for inguinal and unusual affected cartilages. The cause is unknown and hernias such as Spigelian hernia. treatment difficult. Reassurance is important. Clinically there is possibly an overlap with the slipping rib syndrome. HYPERVENTILATION Hyperventilation is typically associated with panic attacks in which the patient feels faint, Spinal lightheaded, sweaty and trembly; the vision may Both visceral sympathetic and somatic nocicep- fade and the patient feel remote from his/her tive afferents converge in the same dorsal horn. surroundings. Numbness or paraethesiae of the Also visceral and somatic noxious stimuli may limbs may be present and there is often a feeling be conveyed in the same spinothalamic tract. of heat or cold with profound tiredness. Chest Thus pain from the spinal muscles or vertebral pain is common with hyperventilation, but bodies may be interpreted as visceral in origin. abdominal pain features less often and is there- of Jorgensen and Fossgreen24 compared 39 patients fore less well recognised.29 In the chronic type http://gut.bmj.com/ with upper abdominal pain without a demon- hyperventilation only a slight increase in respira- strable organic intra-abdominal cause and 28 tory drive over a prolonged period can produce healthy controls. They found that 72% of their the biochemical changes ofhyperventilation,30 so patients also had back pain, compared with 17% these patients rarely recognise that they are ofcontrols. The examinations were blinded with overbreathing. Patients with chronic hyper- regard to the symptoms, 75% ofthe patients with ventilation have been divided into two groups - with back pain had vertebral abnormalities shown at in the first, symptoms are associated on September 26, 2021 by guest. Protected copyright. the physical examination, pointing to some exercise (when they are often referred to a organic mechanism affecting the spine. Most of cardiologist), while in the second symptoms are the findings were localised to the lower thoracic more persistent and unrelated to exercise. and thoracolumbar segments, the same ones that Curiously, hypocapnoea may persist even into innervate the upper gastrointestinal tract. sleep, the PCO2 not returning to normal until Nearly halfoftheir patients had symptoms ofthe well into the night.3' Hyperventilation has been irritable bowel syndrome or heartburn, which thought to cause oesophageal motor disorders32 they felt were significantly related to the back but has not been found to affect colonic motility.33 pain. Ashby25 studied 73 patients in one year in It is useful to ask the patient to hyperventilate his clinical surgical practice whom he considered deliberately; this may reproduce their symp- to have a spinal origin for their abdominal toms. The syndrome has been described as being symptoms. They complained of a burning or responsible for pseudoangina (possible oesopha- sore pain, nagging like toothache. Nearly half geal dysmotility), flatulence, and abdominal had noticed aggravation by posture. Examina- distension.34 tion often showed tenderness near the tip of the vertebral transverse process, which was a par- ticularly valuable sign, interpreted as indicating METABOLIC sensitivity of the adjacent intercostal nerve. Metabolic causes of chronic non-visceral Spinal movements were also assessed and were abdominal pain, such as chronic renal failure, often limited in these patients. Tensing the Addison's disease, porphyria, etc, are well muscles aggravated the pain in almost all cases. recognised and will not be dealt with further An intercostal nerve block gave relief in two here. thirds of his cases and Ashby felt that this broke a spiral ofpain, which he described as the 'spinal reflex pain syndrome'. This was based on the PSYCHOGENIC idea that transient painful trigger stimuli can Psychological factors are inextricably linked to initiate a prolonged cycle of pain and spasm of the genesis of pain.35 The pain is often described the muscle through spinal reflexes, which may be as severe and persistent, having been experi- interrupted by a local anaesthetic breaking the enced for several years and being present without 836 Sharpstonze, Colin-Jones

let up. The pain is inconsistent with the anatomy 8 Fam AG. Approach to musculoskeletal chest wall pain. Primary Care 1988; 15: 767-82. of the nervous system, and no organic patho- 9 Hall PN, Lee APB. Rectus nerve entrapment causing logical or pathophysiological mechanism can be abdominal pain. Br] Surg 1988; 75: 917. 10 Rutgers MJ. The rectus abdominis syndrome: a case report. found responsible. Symptoms are often grossly JNeurol 1986; 233: 180-1. Gut: first published as 10.1136/gut.35.6.833 on 1 June 1994. Downloaded from out of proportion to the physical findings, and 11 Applegate WV. Abdominal cutaneous nerve entrapment syndrome. Surgery 1972; 71: 118-24. the patient usually looks well. It has been 12 Mandelkow H, Loeweneck H. The iliohypogastric and suggested that anxiety and depression may per- ilioinguinal nerves. Surg Radiol Anat 1988; 10: 145-9. 13 Hahn L. Clinical findings and results of operative treatment in petuate the pain by enhancing muscle spasm, ilioinguinal nerve entrapment syndrome. Br j Obstet facilitating spinal reflexes, and then leading to a Gvnaecol 1989; 96: 1080-3. 14 Knockaert DC, D'Heygere FG, Bobbaers HJ. Ilioinguinal preoccupation with the site of the pain. A wide nerve entrapment: a little-known cause of iliac fossa pain. variety of mental disorders affect the perception Postgrad MedJ 1989; 65: 632-5. 15 Starling JR, Harms BA. Diagnosis and treatment of genito- of pain, and range from a depressive illness femoral and ilioinguinal neuralgia. World I Surg 1989; 13: (which often responds to treatment), to hypo- 586-91. 16 Hershield NB. The abdominal wall. ] Clin Gastroenterol 1992; chondriasis and somatoform disorder, which are 14:199-202. much more difficult to manage. 17 Gallegos NC, Hobsley M. Recognition and treatment of abdominal wall pain. ] R Soc Med 1989; 82: 343-4. 18 Scott EM, Scott BB. Painful rib syndrome - a review of 76 In conclusion, the clinician always needs to be cases. Gut 1993; 34: 1006-8. 19 Stevenson FH. Nerve nipping at the intercostal margin. Lancet aware of non-visceral causes for a patient's 1951; ii: 969-70. symptoms. A careful history is crucial, and 20 Clearfield HR. Diagnosing parietal abdominal pain. Hosp Practice 1982; August: 219-27. examination should always include an assess- 21 Fam AG. Musculoskeletal chest wall pain. Can Med Assoc ] ment oftender spots, with Carnett's sign, hyper- 1985; 133: 379-89. 22 Scobie BA. Costochondral pain in gastroenterological practice. aesthesia, and tenderness over the vertebral NEngl]fMed 1975; 295: 1261. bodies. Several authors have found particular 23 Calabro JJ. Costochondritis. N Engli Med 1977; 296: 946-7. 24 Jorgensen LS, Fossgreen J. Back pain and spinal pathology in value in Carnett's sign,'2 which has been shown patients with functional upper abdominal pain. Scand J to be both specific and sensitive.436 It not only Gastroenterol 1990; 25: 1235-41. 25 Ashby EC. Abdominal pain of spinal origin. Ann R Coll Surg relieves the pain and reassures the patient, but 1977; 59: 242-6. also saves a large number of unnecessary and 26 Arroyo JF, Jolliet Ph, Junod AF. Costovertebral joint dys- function: another misdiagnosed cause of atypical chest pain. often unpleasant investigations. Carnett's sign is Postgrad Med3r 1992; 68: 655-9. not infallible; a positive test must always be put 27 Deitch EA, Engel JM. Ultrasonic diagnosis ofsurgical diseases of the anterior abdominal wall. Surg Gynecol Obstet 1980; into the whole clinical picture. None the less, 151: 484-6. following up a positive Carnett's sign with a 28 Hall C, Hall PN, Wingate JP, Neoptolemos JP. Evaluation of herniography in the diagnosis of an occult abdominal wall successful injection of local anaesthetic must be hernia in symptomatic adults. Br]7 Surg 1990; 77: 902-6. one of the most cost effective procedures in 29 Chambers JB, Bland JM. Hyperventilation and irritable bowel syndrome. Lancet 1986; i: 221.

gastroenterology.4 30 Gardner W. Hyperventilation disorders. j R Soc Med 1990; http://gut.bmj.com/ 83: 755-7. 1 Thomson WHF, Dawes RFH, Carter SStC. Abdominal wall 31 Gardner WN, Meah MS. Controlled study of respiratory tenderness: a useful sign in chronic abdominal pain. Br J responses during prolonged measurement in patients with Surg 1991; 78: 223-5. chronic hyperventilation. Lancet 1986; ii: 826-30. 2 Gallegos NC, Hobsley M. Abdominal wall pain: an alternative 32 Valori RM, Cole E, Lemon M, Dunn LA, Cockel R. diagnosis. BrJ Surg 1990; 77: 1167-70. Hyperventilation provokes pain and alters oesophageal 3 Carnett JB. Intercostal neuralgia as a cause of abdominal pain motility in patients with angina-like chest pain. Gut 1989; and tenderness. Surg Gynecol Obstet 1926; 42: 625-32. 30: Al514. 4 Greenbaum DS, Joseph JG. Abdominal wall tenderness test. 33 Maxon DG, Prior A, Whorwell PJ. Effect of hyperventilation Lancet 1991; 337: 1606-7. on distal colonic motility and rectal sensitivity in irritable 5 Gray DWR, Seabrook G, Dixon JM, Collin J. Is abdominal bowel syndrome. Digestion 1991; 48: 70-4. on September 26, 2021 by guest. Protected copyright. wall tenderness a useful sign in the diagnosis of non-specific 34 Gardner WN, Bass C. Hyperventilation in clinical practice. abdominal pain? Ann R Coll Surg 1988; 70: 233-4. Br] Hosp Med 1989; 41: 73-81. 6 Bourne IHJ. Treatment ofpainful conditions ofthe abdominal 35 Jenkins PLG. Psychogenic abdominal pain. Gen Hosp wall with local injections. The Practitioner 1980; 224: 921-5. Psychiatry 1991; 13: 27-30. 7 Simons DG, Travell JG. Myofascial pain syndromes. Textbook 36 Anonymous. Abdominal wall tenderness test: could Carnett ofpain. Edinburgh: Churchill Livingstone, 1984: 263-4. cut costs? [Editorial]. Lancet 1991; 337: 1134.