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
- GI tract
  - 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
- Glands
  - 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
Gynaecological 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
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.

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

By location

Location^[1]

Upper middle abdominal pain
- Stomach (gastritis, stomach ulcer, stomach cancer)
- Pancreas pain[1] (pancreatitis or pancreatic cancer, can radiate to the left side of the waist, back, and even shoulder)
- Duodenal ulcer, diverticulitis
- Appendicitis (starts here, after several times moves to lower right abdomen)
Upper right abdominal pain
- Liver (caused by hepatomegaly due to fatty liver, hepatitis, or caused by liver cancer, abscess)
- Gallbladder and biliary tract (gallstones, inflammation, roundworms)
- Colon pain (below the area of liver - bowel obstruction, functional disorders, gas accumulation, spasm, inflammation, colon cancer)
Upper left abdominal pain
- Spleen pain (splenomegaly)
- Pancreas
- Colon pain (below the area of spleen - bowel obstruction, functional disorders, gas accumulation, spasm, inflammation, colon cancer)
Middle abdominal pain (pain in the area around belly button)
- Appendicitis (starts here)
- Small intestine pain (inflammation, intestinal spasm, functional disorders)
Lower right abdominal pain
- Cecum (intussusception, bowel obstruction)
- Appendix point (Appendicitis location)
Lower left abdominal pain
- Sigmoid colon (polyp, sigmoid volvulus, obstruction or gas accumulation)
Pelvic pain
- bladder (cystitis, may secondary to diverticulum and bladder stone, bladder cancer)
- pain in women (uterus, ovaries, fallopian tubes)
Right lumbago and back pain
- liver pain (hepatomegaly)
- right kidney pain (its location below the area of liver pain)
Left lumbago and back pain
- less in spleen pain
- left kidney pain
Low back pain
- kidney pain (kidney stone, kidney cancer, hydronephrosis)
- Ureteral stone pain

Diagnostic approach

When a physician assesses a patient to determine the etiology and subsequent treatment for abdominal pain the patient's 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, amylase 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)

Management

Butylscopolamine (Buscopan) is used to treat cramping abdominal pain with some success.^[2]

References

^ Richard F.LeBlond. Diagnostics. US: McGraw-Hill Companies, Inc. ISBN 0-07-140923-8.
^ Tytgat GN (2007). "Hyoscine butylbromide: a review of its use in the treatment of abdominal cramping and pain". Drugs. 67 (9): 1343–57. PMID 17547475.