Anesthesia: The pain memory

Acute pain is defined as pain with a duration of less than 3 months. This usually has a protective function and can usually be treated well or very well with suitable analgesics.

Why early adequate analgesia is necessary

If acute pain is not treated correctly, the pain can become independent - the so-called pain memory develops.

Even if the cause of the acute pain no longer existend, the pain continues, the actually protective function is reversed into an independent clinical picture.
This chronic pain is often characterized by increased sensitivity of affected areas (hyperalgesia, allodynia) and its therapy is also much more difficult than that of acute pain as the response to analgesics is usually significantly reduced.

Chronic pain not only has a strong influence on the quality of life but also on various processes such as:

• increased infections and immunosuppression
• mental effects: Fatigue and exhaustion, decreased sleep quality, cerebral dysfunction, irritability
• circulatory disorders
• inappetence
• muscle atrophy (inactivity)
• tumor activity

...and thus on the general health of our patients!

→ The aim of pain therapy is therefore also to prevent the development of this pain memory through early pain management or to reduce the risk for its development. To avoid any chronicity the earliest possible recognition of pain is essential.

Early pain management is particularly important in the presence of osteoarthritis, as increased inactivity can worsen and further chronify it over time.

The therapy of chronic pain includes a multimodal management consisting of:

• weight reduction (!)
• physiotherapy
• complementary medicine like laser, acupuncture
• nutritional adjustment
• the (combined) administration of analgesics
• in some cases also surgical interventions

Hints around pain:

• in older patients 7 years plus, performing  diagnostic images as soon as possible is required (osteoarthrosis, resorptive lesions/other dental diseases, tumors)
• Diagnostic therapy : administration of analgesics (sufficiently dosed, also combinations of several analgesics) can be tried before thinking of a real behavioral problem
• Combination of analgesics: Synergistic effect (combined pain therapy) - can lower single doses but hat potentiated effects ; especially needed and effective in chronic pain.
• Age or pre-existing conditions are not reasonable reasons to deny a patient pain therapy. There are sufficient agents available that can and should be used even in polymorbid patients.
• in case of permanent administration of NSAID's regular laboratory controls of organ parameters as well as small blood count
• in the context of a surgery, local anesthetics interrupt local pain transmission and thus reduce allodynia and hyperalgesia - their use is therefore also useful in dentistry and is increasingly being applied.
• Therefore, to reduce the risk of phantom pain in limb amputation as much as possible, it has proven useful to anesthetize the nerve generously using local anesthetics before amputation (allow sufficient time for effect!).

Bibliography: Upon request

Author of the article:

Veterinarian med. vet. Julia Brüner