Doctor

Take warning signals seriously

Acute pain is the normal, predictable physiological response to an injurious (noxious) stimulus. It can be clearly located, and its intensity correlates with the stimulus.

In contrast to chronic pain, it is of limited duration and subsides on termination of the damage or healing. Acute pain has a warning and protective function: It indicates existing damage and prevents further damage by initiating avoidance reactions.

Pathophysiology

Activity of the Pain Sensors

Acute pain results from any condition that stimulates the body’s “pain sensors” (nociceptors), such as injuries, bleeds (haemorrhages), tumours, infections, and metabolic and endocrine problems. Acute pain usually occurs after surgery, physical injury or sports injuries.

Acute pain is caused by a pain stimulus that excites the pain receptors (nociceptors), which transmit stimuli to the spinal cord. The pain stimulus can then be diverted to the motor neurons, evoking a reflex response such as withdrawing a limb. Then the pain stimulus is transmitted to supra-spinal structures involved in pain processing and eventually reaches the brain, where it is perceived as pain. Supra-spinal reflexes also activate the heart and respiratory rate and induce the release of stress hormones.

Diagnosis

Assessment and Help

In acute pain, the underlying cause is often obvious, e.g. after surgery or an acute trauma. Many times, however, the exact underlying pathology is not clear and a diagnostic work-up is necessary. Key elements include:

  • Performance of a full physical examination
  • Assessment of pain location, severity, quality, onset and aggravating/relieving factors (for a rapid and simple assessment of the pain severity, pain scales can be used as a validated measurement tool)
  • Utilisation of specific diagnostic procedures such as X-rays or bone scans
... Click here for more information on pain scales for measuring pain

M-N/A-UK-03-24-0008 - March 2024