What Is Visceral Pain?

A Type of Pain That Can Be Hard to Pinpoint and Describe

Senior patient suffering from backache
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Visceral pain is a type of nociceptive pain that comes from the internal organs. As with somatic pain, pain receptors called nociceptors send signals to the spinal cord and brain when damage is detected. Unlike somatic pain, however, visceral pain is harder to pinpoint in terms of location within the body.

Some types of pelvic pain and abdominal pain, such as those caused by bladder disorders or irritable bowel syndrome, are considered to be visceral pain disorders.

What Visceral Pain Feels Like

Visceral pain is often described as generalized aching or squeezing. It is caused by compression in and around the organs, or by stretching of the abdominal cavity. Sometimes visceral pain may radiate to other areas in the body, making it even harder to pinpoint its exact location.

The Difference Between Superficial and Deep or Visceral Pain

When you cut your finger with a knife, you experience sharp and rapid pain. But deeper organs (like your intestines or bladder) lack receptors that convey sharp and rapid pain—thus the quality and timing of visceral pain is different from superficial pain.

Furthermore, when you cut your finger, you know where the pain is—in other words, you are able to localize it. But with deeper, visceral pain, it is harder to tell exactly where the source of the pain is, as pain is often referred. For example, pain from the heart can be felt in the left arm and neck, and bladder pain may be felt in the perineum.

In addition, systemic, or system-wide symptoms, typically accompany visceral pain, such as nausea, sweating, paleness, and changes in blood pressure, heart rate, and temperature. Finally unlike superficial pain, visceral pain tends to radiate to other body parts making the whole pain experience more diffuse and markedly unpleasant.

Overall, the reason for the difference in the location and timing of visceral pain versus somatic pain is due to the low number of sensory receptors found in the viscera (your internal organs). 

Simulating Visceral Pain in the Lab

In an experiment to stimulate visceral pain, researchers attached a balloon to a tube and then inflated this balloon while in the stomach. Researchers were thus able to better appreciate the severe nature of visceral pain and found that its greatest with organ distension.

Applying this lab experiment to real life, if you have a small bowel obstruction, the intestines distend and cause intestinal colic. Colic describes pain that waxes and wanes. As the intestines continue to distend, inflammation and organ injury occur, which is especially sensitive to even the most minor stimuli, such as movement. If you've ever seen a person with bowel obstruction, you know that even the most subtle movements can bring on severe pain.

Treatment of Visceral Pain

Visceral pain responds well to weak opioids such as codeine, though stronger opioids such as morphine may also be used. That being said, opioids can cause unpleasant side effects like constipation and sleepiness. They also carry the risk of a person developing tolerance and/or addiction.

 

The good news is that experts are researching better therapies to treat visceral pain disorders. For example, the medication Lyrica (Pregabalin) is used to treat fibromyalgia, a visceral pain condition that causes diffuse muscle tenderness, along with other symptoms. 

Sources:

Barrett KE, Barman SM, Boitano S, Brooks HL. Somatosensory Neurotransmission: Touch, Pain, & Temperature. In: Barrett KE, Barman SM, Boitano S, Brooks HL. eds. Ganong’s Review of Medical Physiology, 25e. New York, NY: McGraw-Hill; 2016. 

Sikandar S, Dickenson AH.Visceral Pain - the Ins and Outs, the Ups and DownsCurr Opin Support Palliat Care. 2012 Mar;6(1):17-26.

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