Abdominal Pain

The following is an incomplete list of possible causes of abdominal pain.

• Gastrointestinal
  • Inflammatory: gastroenteritis, appendicitis, gastritis, esophagitis, diverticulitis, Crohn's disease, ulcerative colitis, microscopic colitis
  • Obstruction: hernia, intussusception, volvulus, post-surgical adhesions, tumours, superior mesenteric artery syndrome, severe constipation, hemorrhoids
  • Vascular: embolism, thrombosis, hemorrhage, sickle cell disease, abdominal angina, blood vessel compression (such as celiac artery compression syndrome)
  • digestive: peptic ulcer, lactose intolerance, celiac sprue (affecting 1:133 people), food allergies, Jasohnstritis
  • Bile system
    • Inflammatory: cholecystitis, cholangitis
    • Obstruction: cholelithiasis, tumours
    • Liver
      • Inflammatory: hepatitis, liver abscess
      • Pancreatic
        • Inflammatory: pancreatitis
        • Renal and urological
          • Inflammation: pyelonephritis, bladder infection
          • Obstruction: kidney stones, urolithiasis, Urinary retention, tumours
          • Vascular: left renal vein entrapment
          • Gynecological or obstetric
            • Inflammatory: pelvic inflammatory disease
            • Mechanical: ovarian torsion
            • Endocrinological: menstruation, Mittelschmerz
            • Tumors: endometriosis, fibroids, ovarian cyst, ovarian cancer
            • Pregnancy: ruptured ectopic pregnancy, threatened abortion
            • Abdominal wall
              • muscle strain or trauma
              • muscular infection
              • neurogenic pain: herpes zoster, radiculitis in Lyme disease, abdominal cutaneous nerve entrapment syndrome (ACNES), tabes dorsalis
              • Referred pain
                • from the thorax: pneumonia, pulmonary embolism, ischemic heart disease, pericarditis
                • from the spine: radiculitis
                • from the genitals: testicular torsion
                • Metabolic disturbance
                  • uremia, diabetic ketoacidosis, porphyria, C1-esterase inhibitor deficiency, adrenal insufficiency, lead poisoning, black widow spider bite, narcotic withdrawal
                  • Blood vessels
                    • aortic dissection, abdominal aortic aneurysm
                    • Immune system
                      • sarcoidosis
                      • vasculitis
                      • familial Mediterranean fever
                      • Idiopathic
                        • irritable bowel syndrome (affecting up to 20% of the population, IBS is the most common cause of recurrent, intermittent abdominal pain)

Acute Abdominal Pain

Acute abdomen can be defined as severe, persistent abdominal pain of sudden onset that is likely to require surgical intervention to treat its cause. The pain may frequently be associated with nausea and vomiting, abdominal distention, fever and signs of shock. One of the most common conditions associated with acute abdominal pain is acute appendicitis, a condition where mucus or fecal matter hardens, becomes rock-like, and blocks the opening.
Selected causes of acute abdomen

• Traumatic : blunt or perforating trauma to the stomach, bowel, spleen, liver, or kidney
• Inflammatory :
  • Infections such as appendicitis, cholecystitis, pancreatitis, pyelonephritis, pelvic inflammatory disease, hepatitis, mesenteric adenitis, or a subdiaphragmatic abscess
  • Perforation of a peptic ulcer, a diverticulum, or the caecum
  • Complications of inflammatory bowel disease such as Crohn's disease or ulcerative colitis
  • Mechanical :
    • Small bowel obstruction secondary to adhesions caused by previous surgeries, intussusception, hernias, benign or malignant neoplasms
    • Large bowel obstruction caused by colorectal cancer, inflammatory bowel disease, volvulus, fecal impaction or hernia
    • Vascular : occlusive intestinal ischemia, usually caused by thromboembolism of the superior mesenteric artery

Recurrent Abdominal Pain in Children and Adolescents

Recurrent abdominal pain (RAP) occurs in 5–15% of children 6–19 years old. In a community-based study of middle and high school students, 13–17% had weekly abdominal pain. Using criteria for irritable bowel syndrome (IBS), 14% of high school students and 6% of middle school students fit the criteria for adult IBS. As with other difficult to diagnose chronic medical problems, patients with RAP account for a very large number of office visits and medical resources in proportion to their actual numbers. Most patients with RAP benefit from reassurance and techniques to manage anxiety and stress, which are frequently associated with episodes.