In general, following SCI, there are three types of pain, based on where in the body the pain is felt: somatic, visceral, and neuropathic. Pain of all three types can be either acute or chronic. Acute pain is short lasting and usually manifests in ways that can be easily described and observed. Chronic pain is defined as pain lasting more than three months. It is much more subjective and not easily described as acute pain. The three pain types can be felt at the same time or singly and at different times. The different types of pain respond differently to the various pain medications. Somatic and visceral pain are easier to treat than neuropathic pain.
Somatic pain is caused by the activation of pain receptors in either the body surface or musculoskeletal tissues. A common cause of somatic pain in SCI persons is postsurgical pain from the surgical incision. It is usually described as dull or aching. Somatic pain, that is a complication of SCI, occurs with increased frequency in the shoulder, hip, and hand, although it also occurs in the lower back and buttocks. Somatic pain is probably caused by a combination of factors, such as abnormalities that may have always been there, inflammation, repetitive trauma, excessive activity, vigorous stretching, and contractions due to paralysis, spasticity, flabbiness, disuse and misuse. Generally speaking, somatic pain is usually aggravated by activity and relieved by rest.
Visceral pain is the pain we feel when our internal organs are damaged or injured and is by far the most common form of pain. Viscera refers to the internal areas of the body that are enclosed in a cavity. Visceral pain is caused by the activation of pain receptors in the chest, abdomen or pelvic areas. Visceral pain is vague and not well localized and is usually described as pressure-like, deep squeezing, dull or diffuse. Visceral pain is caused by problems with internal organs, such as the stomach, kidney, gallbladder, urinary bladder, and intestines. These problems include distension, perforation, inflammation, and impaction or constipation, which can cause associated symptoms, such as nausea, fever, and malaise, and pain. Visceral pain is also caused by problems with abdominal muscles and the abdominal wall, such as spasm.
Neuropathic pain is caused by injury or malfunction to the spinal cord and peripheral nerves. Neuropathic pain is typically a burning, tingling, shooting, stinging, or “pins and needles” sensation. Some people also complain of a stabbing, piercing, cutting, and drilling pain. This type of pain usually occurs within days, weeks, or months of the injury and tends to occur in waves of frequency and intensity. Neuropathic pain is diffuse and occurs at the level or below the level of injury, most often in the legs, back, feet, thighs, and toes, although it can also occur in the buttocks, hips, upper back, arms, fingers, abdomen, and neck.