Pain is a common complaint in the medical practice. It is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage; or described in terms of such damage. It is a subjective measurement. Description of the pain includes eight characteristics namely the site, character, severity, radiation, temporal relationship, associated symptoms, aggravating and relieving factors. Depending on the temporal relationship of the pain it is further classified as acute and chronic pain, and this article points out the differences between these two terms.
The pain, which persists past the time of healing or for more than about 3 months, is called the chronic pain. Sometimes acute pain can become chronic if it persists after 10-14 days of the onset.
Pain pathway comprises afferent and efferent fibers where C fibers are responsible for carrying the chronic, so called visceral pain.
Most of the time chronic pain is associated with the psychological disturbances. Clinically a patient with chronic pain commonly presents with the limitation of social, mental and psychological activities, subdued, sad or sleepy in his facial expressions or with vegetative symptoms such as sleep disturbances, irritability or with loss of appetite.
Chronic pain is poorly localized, and it is dull and vague in its character. It is often periodic and builds peaks. The pain may be referred to other areas associated with internal factors and often associated with nausea, vomiting and ill feeling.
Management includes non pharmacological and pharmacological therapies.
Acute pain, which is also known as somatic pain, is of sudden onset.
Large myelinated A delta fibers are responsible for carrying the acute pain.
Clinically a patient with acute pain presents with increased autonomic activity, which is manifested as tachycardia, hypertension, sweating, reduced intestinal mortality, increased rate and reduced depth of respiration and with facial grimaces. Acute pain can also be exacerbated by psychological factors such as sleeplessness, anxiety, depression or anger. As mentioned above acute pain can become chronic or it can be superimposed on chronic pain.
Acute pain is well localized, and the radiation may follow the distribution of somatic nerves. It is sharp and defined in its character, and it hurts where the stimulus is associated with the external factors. Acute pain is often a constant pain and nausea and vomiting are uncommon unless it is of deep somatic pain to bone involvement.
Management of acute pain includes the drug therapy; mainly opioids and non steroidal anti inflammatory drugs and the regional blockers.
What is the difference between Chronic and Acute Pain?
• While acute pain is of sudden onset and resolves within a short time, chronic pain is of insidious onset and persists past the time of healing or for more than about 3 months.
• In acute pain, the site is well localized, but chronic pain is poorly localized.
• Radiation of the acute pain may follow the distribution of somatic nerve, but radiation of chronic pain is diffuse.
• Acute pain is sharp and defined in its character, but chronic pain is dull and vague.
• Acute pain is often constant, but chronic pain is often periodic and builds peaks.
• Chronic pain is often associated with nausea, vomiting and ill feeling but acute pain is usually not.