ABDOMINAL PAIN

ABDOMINAL PAIN

There are four types of abdominal pain:

1.  Visceral. Gut organs are insensitive to stimuli such as burning and cutting but are sensitive to distension, contraction, torsion and stretching. Pain from unpaired structures is usually but not always felt in the midline.
2. Parietal. The parietal peritoneum is innervated by somatic nerves, and its involvement by disease processes, e.g. inflammation, infection or neoplasia, causes sharp, well-localised and lateralised pain.
3. Referred pain. (For example, gallbladder pain is referred to the back or shoulder tip.)
4. Psychogenic. Cultural, emotional and psychosocial factors influence everyone's experience of pain. In some patients, no organic cause can be found despite investigation, and psychogenic causes ( e. g. depression) may be responsible.

CAUSES OF ACUTE ABDOMINAL PAIN ('SURGICAL'):

Inflammation: Appendicitis, Diverticulitis, Cholecystitis, Pelvic inflammatory disease      Pancreatitis, Pyelonephritis, Intra-abdominal abscess.

Perforation/rupture: Peptic ulcer, Diverticular disease, Ovarian cyst, Aortic aneurysm.

Obstruction:  Intestinal obstruction, Biliary colic, Ureteric colic.  

Other (rare)

 'EXTRAINTESTINAL' CAUSES OF CHRONIC OR RECURRENT ABDOMINAL PAIN

Retroperitoneal:, Aortic aneurysm, Malignancy, Lymphadenopathy, Abscess.

Psychogenic: Depression, Anxiety, Hypochondriasis, Somatisation

Locomotor: Vertebral compression, Abdominal muscle strain.

 Metabolic/endocrine: Diabetes mellitus, Addison's disease, Acute intermittent porphyria, Hypercalcaemia.

Haematological:  Sickle-cell disease, Haemolytic disorders

Neurological:  Spinal cord lesions, Tabes dorsalis, Radiculopathy

IMPORTANT FACTORS IN THE ASSESSMENT OF ABDOMINAL PAIN

1. Duration 2. Site and radiation 3. Severity 4. Precipitating and relieving factors (food, drugs, alcohol, posture, movement, defaecation) 5.Nature (colicky, constant, sharp or dull, wakes patient at night) 6. Pattern (intermittent or continuous) 7. Associated features (vomiting, dyspepsia, altered bowel habit). The initial choice of investigations will obviously depend on the clinical features elicited during the history and examination:

• Epigastric pain, dyspepsia and relationship to food suggest gastroduodenal or biliary disease. Endoscopy and ultrasound are indicated.
• Altered bowel habit, rectal bleeding or features of obstruction suggest colonic disease. Barium enema and sigmoidoscopy, or colonoscopy are indicated.
• Pain provoked by food in a patient with widespread atherosclerosis may indicate mesenteric ischaemia. Mesenteric angiography may be necessary.
• Persistent symptoms require exclusion of colonic or small bowel disease. However, young patients with pain relieved by defecation, bloating and alternating bowel habit are likely to have irritable bowel syndrome . Simple investigations (blood tests and sigmoidoscopy) may be sufficient.
• Upper abdominal pain radiating to the back, a history of alcohol misuse, weight loss and diarrhoea suggest chronic pancreatitis or pancreatic cancer. Ultrasound, CT and pancreatic function tests are required.
• Recurrent attacks of pain in the loins or radiating to the flanks with urinary symptoms should prompt investigation for renal or ureteric stones by ultrasound and intravenous urography.
• A past history of psychiatric disturbance, repeated negative investigations or vague symptoms which do not fit any particular disease or organ pattern may point to a psychological origin for the patient's pain . Careful review of case notes and previous investigations, along with open and honest discussion with the patient, may reduce the need for further cycles of unnecessary and invasive tests. Care must always be taken, however, not to miss rare pathology or atypical presentations of common diseases.

CONSTANT ABDOMINAL PAIN 

Patients with chronic pain which is constant or nearly always present will usually have features to suggest the underlying diagnosis, e.g. malignancy (gastric, pancreatic, colonic, hepatic metastases), chronic pancreatitis or intra-abdominal abscess. In a minority no cause will be found despite thorough investigation, leading to the diagnosis of 'chronic functional abdominal pain'. In these patients a psychological cause is highly likely, and the most important tasks are to provide symptom control, if not relief, and to minimise the effects of the pain on social, personal and occupational life. Patients are best managed in specialised pain clinics where, in addition to psychological support, appropriate use of drugs including amitriptyline, gabapentin, ketamine and opioids may be necessary