Visceral pain is experienced when pain receptors in the abdominal organs are stimulated. The pain is usually dull, difficult to pinpoint to a particular location and is felt in the midline. It is generally described as cramping, gnawing or burning and is often accompanied by sweating, nausea and vomiting. The person suffering from visceral pain is often restless and constantly moves about in an attempt to relieve the discomfort. An example is the pain of intestinal obstruction.

Somatoparietal pain arises from irritation of the lining of the abdominal cavity (peritoneum). It is more intense and more precisely localized than visceral pain; and is aggravated by movement, coughing or sneezing; so that the sufferer lies absolutely still in order to reduce the pain. Another characteristic feature of peritoneal irritation is a relief spasm of the abdominal musculature, localized to the involved area. An example of this kind of pain is that caused by irritation of the peritoneal lining by acid gastric juice due to a perforated peptic ulcer.

Referred pain is felt in areas far away from the diseased organ due to the nerve supply arising from the same spinal segments. Pain arising from the gallbladder, for instance may be felt in the right upper back or shoulder. There are some characteristics of abdominal pain such rapidity of onset, location duration and intensity that can give the physician as well as the patient some idea about the cause.

• Pain that is of sudden onset severe and well localized is likely due to an intra abdominal catastrophe such as a perforation.
• Pain is self-limiting and subsides in disorders such as gastroenteritis.
• Pain in the upper abdomen above the naval can be from pancreatitis of from a performed peptic ulcer.
• Pain in the right upper portion of the abdomen could be from the gallbladder or liver.
• Pain originating in the small intestine is felt around the umbilicus.
• Pain can also spread from its original site to another as in appendicitis, where it starts around the umbilicus and then spreads to the right lower portion of the abdomen.
• Although it is hard to be objective about the pain intensity due to variations in the pain threshold among individuals, the severity of pain is loosely related to the magnitude of the disease process.
• The character of the pain (dull aching spasmodic, crampy or severe boring) can also suggest its origin.

This usually begins with vague pain around the umbilicus and nausea. Within 6 to 8 hours, the pain moves to the right lower portion of the abdomen and tenderness (ie, severe pain when this area is pressed) occurs along with low-grade fever.

This is an inflammation of the gallbladder usually secondary to gallstones and is characterized by pain in the right upper abdomen, which radiates to the right upper back and shoulder. Accompanying symptoms include nausea, vomiting, low-grade fever with chills and obvious jaundice; it could be due to stones in the bile ducts with infection.

This usually begins with acute-onset upper abdominal pain that rapidly increases in severity and radiates to the back or left shoulder. It is a constant unrelenting pain which is often reduced by sitting up and leaning forward. There is associated nausea, vomiting, abdominal bloating and ‘tightness’ with inability to pass wind or motion. In severe cases there may be a rapid heart rate, drop in blood pressure and breathing difficulty. The common causes of acute pancreatitis are alcoholism and gallstones and hence a history of chronic alcohol intake or a recent binge, or a known of gallstones will be useful.

As already mentioned, the pain is sudden, sharp, intensely severe and present initially over the upper abdomen and later spreads to the entire abdomen. Movement increases the pain and there may be an increase in heart rate and difficulty in breathing. Fever and drop in blood pressure may happen within a few hours.

This produces crampy pain around the naval associated with abdominal distension and vomiting of copious amounts of bilious material, restlessness, fever, increase in heart rate and sometime audible intestinal rumbles.

This is characterized by cramps around the navel, with diarrhea, sometimes with blood and mucus, with or without vomiting and fever. Most cases are self-limiting or respond rapidly to antibiotics and fluid replacement. There may be a history of other family members or friends affected at the same time. Gynaecological causes, such as endometriosis, twisted ovarian cyst or ruptured tubal pregnancy and urological causes such as kidney stones should not be overlooked.

Abdominal pain can also originate from disorders involving extra abdominal organs and systemic illnesses. Examples include acute myocardial infarction (heart), pneumonia (lung), disc prolapse, spinal cord tumors (nervous system), metabolic (renal failure diabetes), toxic (lead poisoning), infections (herpes zoster) and muscle contusions or haematomas.

It is therefore extremely important to consult the nearest physician or the Emergency Department when one has abdominal pain with any of the characteristics described above. Even if the cause of the pain turns out to be innocuous, it is better to err on the side of caution than to land up with an abdominal catastrophe!