Abdominal pain

Abdominal pain (or stomach ache) can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem. Most frequently the cause is benign and/or self-limited, but more serious causes may require urgent intervention.

Differential diagnosis

• 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), Postural orthostatic tachycardia syndrome
  • digestive: peptic ulcer, lactose intolerance, coeliac disease, food allergies
• 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.

Diagnostic approach

When a physician assesses a patient to determine the etiology and subsequent treatment for abdominal pain the patients history of the presenting complaint and physical examination should derive a diagnosis in over 90% of cases.

It is important also for a physician to remember that abdominal pain can be caused by problems outside the abdomen, especially heart attacks and pneumonias which can occasionally present as abdominal pain.

Investigations that would aid diagnosis include

• Blood tests including full blood count, electrolytes, urea, creatinine, liver function tests, pregnancy test and lipase.
• Urinalysis
• Imaging including erect chest X-ray and plain films of the abdomen
• An electrocardiograph to rule out a heart attack which can occasionally present as abdominal pain

If diagnosis remains unclear after history, examination and basic investigations as above then more advanced investigations may reveal a diagnosis. These as such would include

• Computed Tomography of the abdomen/pelvis
• Abdominal or pelvic ultrasound
• Endoscopy and colonoscopy (not used for diagnosing acute pain)

See also

• Abdominal examination

References