Pain

Pain corresponds to various pathological processes.

It is expressed differently depending on the patient, age, culture.

It is a deeply subjective sensation, which means that only the patient can appreciate the intensity.

Regular assessment of pain intensity is essential to prescribe effective treatment.

Clinical signs:

– Assessment of pain:

• Intensity: use a simple verbal scale in children over 5 years and adults and NFCS or FLACC scales in children under 5 years.

• appearance Circumstance: sudden, intermittent, chronic; at rest, at night, during a movement, during care, etc.

• Type: burning, cramping, spasm, gravity, radiation, etc.

• Aggravating factors, relieving factors, etc.

– Clinical examination:

• In the area where localized pain.

• Search specific signs of an underlying pathology (p. Ex. Bone or musculoskeletal pain may correspond to a vitamin C deficiency) and review different devices.

• Associated signs such as fever, weight loss, etc.

– Summary:

The synthesis of information collected during the interrogation and clinical examination to clarify the cause and guide treatment. It is important to distinguish:

• The nociceptive pain: it is most often acute pain and

causal relationship is usually obvious (p. ex. postoperative acute pain, burns, trauma, renal colic, etc.). The pain can take many forms but the neurological examination is normal. Their treatment is relatively well codified.

• Neuropathic pain due to nerve damage (section, stretching, ischaemia): it is most often chronic pain. On a permanent painful background such paresthesia, burning, cramping, piggyback paroxysmal components like electric shocks, frequently accompanied by neurological disorders (anesthesia, hypo or hyperesthesia). These pains occur in viral infections directly affecting the CNS (herpes zoster), tumor compression, trauma (amputation), paraplegia, etc.

• The pain of mixed origin (cancer, HIV) whose management requires a more holistic approach.

Assessment of pain scales:

Self Assessment Scale – Children over 5 years and adults

Hetero assessment scale – Children from 2 months to 5 years

Hetero assessment scale – Children under 2 months

A score greater than or equal to 2 results in severe pain requiring pain treatment.

Treatment:

Treatment depends on the type of pain and its intensity. It is both symptomatic and etiologic when a treatable cause is found and only symptomatic in other cases (no cause found, incurable disease).

Nociceptive pain:

WHO has classified analgesics acting on the pain in 3 levels:

– Level 1: non-opioid analgesics, represented by acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs).

– Level 2: weak opioid analgesics, represented by codeine and tramadol.

Their association with one or two level 1 analgesics is recommended.

– Level 3: strong opioid analgesics, whose leader is morphine. Their association with one or two level 1 analgesics is recommended.

The treatment of pain is based on some fundamental concepts:

– The pain can not be treated properly if it is properly evaluated. The patient is the only person able to assess the intensity of his own pain.

Using a rating scale is indispensable.

– The results of the evaluations should be noted in the patient’s file as well as other vital signs.

– The pain must be as early as possible.

– It is recommended to administer analgesics with anticipation (eg before a painful care..).

– Analgesics should be prescribed and administered systematically at fixed times (not demand).

– The oral form should be used whenever possible.

– The combination of several molecules (multimodal analgesia) should be preferred.

– Start immediately by the presumed effective level: p. eg in case of fracture of the femur, begin immediately by a level 3 analgesic.

– The choice of treatment and the dose is guided not only by evaluating the intensity of the pain but also by the patient response can be extremely variable from one individual to another.

Notes on use of opioids:

– Morphine is the effective treatment of large numbers of severe pain. Its analgesic effect is dose-dependent. Its side effects have often been exaggerated and should not be a barrier to treatment.

– The major side effect of opioids is respiratory depression, which can sometimes be life threatening. It only occurs overdose, so it is important to gradually increase the dosage. Respiratory depression is preceded by drowsiness which is a warning and lead to measure the respiratory rate (RR).

The FR should fall below the thresholds indicated below:

Respiratory depression should be promptly detected and treated: physical and verbal stimulation of the patient; oxygen administration; respiratory support (balloon and mask) if necessary. In the absence of improvement, administer naloxone (morphine antagonist) way titrated bolus January-March micrograms / kg up to the normalization of the FR and the disappearance of excessive sleepiness.

– Morphine and codeine always cause constipation. A laxative should be routinely prescribed if the analgesic treatment continues beyond 48 hours: PO lactulose is the drug of choice: children <1 year: 5 ml / day; children 1 to 6 years: 5 to 10 ml / day; Children 7 to 14 years: 10 to 15 ml / day; Adult: 15 to 45 ml / day).

In case of loose stools, preferably use a stimulant laxative (bisacodyl PO: Children> 3 years: 5 to 10 mg / day; adults: 10-15 mg / day).

– Nausea and vomiting are common early in treatment.

In adults, haloperidol PO (oral solution 2 mg / ml): 1-2 mg repeated up to 6 times / day.

Metoclopramide PO may also be used (children: 5 to 15 mg / day in 3 divided doses Adult: 15 to 30 mg / day in 3 divided doses). Do not combine the two drugs.

– For chronic pain from an illness at an advanced stage (cancer, AIDS, etc.), PO morphine is the drug of choice. It may be necessary to increase doses over months depending on the assessment of pain. Do not hesitate to administer the doses needed and effective.

– Morphine, tramadol and codeine have similar modes of action and should not be associated.

– Buprenorphine, nalbuphine and pentazocine oppose the analgesic effects of morphine, pethidine, tramadol and codeine: do not associate.

Neuropathic pain:

These pains are often ineffective, to standard analgesics.

Their treatment is based on the combination of two centrally acting drugs:

amitriptyline PO

Adults: start with 10 to 25 mg / once daily in the evening and gradually increase to the effective dose does not exceed 150 mg / day in the evening made. Reduce dose by half in elderly patients.

carbamazepine PO

Adults: start with 200 mg / day in the night for one week, then 400 mg / day in 2 divided doses (morning and evening) the following week, then 600 mg / day in 3 divided doses.

In women of childbearing potential, given the teratogenic risk, the use of carbamazepine may be considered only under cover of a non-hormonal contraceptive (IUD copper).

Pain of mixed origin:

In mixed nociceptive pain strong component, such as in cancer or AIDS, morphine is combined with antidepressants or anticonvulsants.

Chronic pain:

Unlike acute pain, in chronic pain, medical treatment alone is not always possible to obtain sufficient analgesia. A multidisciplinary approach also involving physiotherapy, psychotherapy, hygiene care is often necessary, both to relieve the patient and to allow him to better manage his pain.

Co-analgesics:

The association of some drugs may be useful, even essential in the treatment of pain: antispasmodics, muscle relaxants, anxiolytics, corticosteroids, local anesthetics, etc.