The principal treatment responsibility of pain patients lies with the primary health care. Specialists are consulted with when necessary. A good treatment relationship with the own family doctor is fundamental in the treatment of chronic pain.
The tasks in the primary health care include
clinical examination of pain patients (history and physical examination), complemented if necessary with further tests available in the primary care, with the aim of
identifying the type of pain (nociceptive, neuropathic, other)
diagnosing the underlying disease causing the pain
mapping of the psychosocial background factors that may contribute to the pain becoming chronic: the patient's own view of the pain and its significance, the patient's mood using DEPS screening, occupational and family situation, use of alcohol or drugs
causal or symptomatic treatment of pain according to the local agreements concerning the division of responsibilities between primary and specialised care.
Patients in whom the pain cannot be sufficiently relieved in the primary care are referred to specialized care.
Pain is documented on every visit by using a visual analogue scale (VAS) for pain (0-10), a numerical rating scale (NRS; 0-10) or a pain drawing.
Rehabilitation is arranged for patients with poor treatment response to help with adapting to and coping with the symptoms.
General
Pain in considered chronic when it has continued for more than 3 months or has lasted longer than what is the normal healing time of tissues.
Neuropathic pain is caused by a damage in the pain pathway itself.
Depression, suffering and anxiety are often associated with chronic pain. The patient's psychosocial condition is taken into account in treatment and rehabilitation.
The pathophysiology of the pain is assessed as carefully as possible and treatment is planned according to the aetiology of pain.
By treating acute pain as well as possible, pain can be prevented from becoming chronic.
Types of chronic pain
Nociceptive pain
Pain arising purely from tissue injury (nociperception = perception of tissue injury)
Ischaemic pain
Musculoskeletal pain
Infection pain
Degenerative pain in connective tissues
The cause of the pain is outside the nervous system.
Nociceptive pain may also involve sensitization to touch in the corresponding skin area.
Long-term pain in the extremities in particular, may activate the sympathetic nervous system, appearing as a change in the temperature and colour of the limb.
Neuropathic pain
A logical neuro-anatomical location of the pain, and findings in clinical examination that are in accord with the abnormal function of sensation are prerequisites for the diagnosis of neuropathic pain.
As a result of changes in the nervous system, the function of sensation is abnormal so that a stimulus that earlier was painless, e.g. touch, may cause intense pain (allodynia). On the other hand, decreased sensation for various stimuli may be found.
Unilateral pains following disturbances of cerebral circulation
Deafferentation pain associated with spinal cord injury
Both peripheral and central nerve injury may be the underlying cause in postherpetic and phantom pain.
Idiopathic pain
Chronic pain is categorized as idiopathic when it is not caused by tissue or nerve damage and the diagnostic criteria for the chronic pain syndrome are not met.
The most common condition of idiopathic pain is fibromyalgia Fibromyalgia.
An exercise program based on patient's own activity and aimed at preserving physical condition and functional ability is essential in the treatment Exercise for Fibromyalgia.
In chronic pain syndrome (ICD-10: persistent somatoform pain disorder, F45.4) the predominant complaint is of persistent, severe, and distressing pain, which cannot be explained fully by a physiological process or a physical disorder. The pain occurs in association with emotional conflict or psychosocial problems that are sufficient to allow the conclusion that they are the main causative influences.
A good patient-doctor relationship is the basis of treatment. Appropriate investigations for differential diagnostics should be performed but repetition of the examinations should have clear grounds.
Pharmacological treatment has not a too central role. Tricyclic antidepressants or SNRIs (duloxetine, milnacipran, venlafaxine) may be tried if needed because the patients may have changes in the CNS neurotransmitter concentrations similar to patients with depression.
Thorough history: the start and development of the symptoms, earlier examinations and treatments, present symptoms and functional ability, life situation, family, community factors at work etc.
A visual analogue scale (VAS; scale 0-10, 0 = no pain at all, 10 = worst conceivable pain) or a numerical rating scale (NRS; 0-10) is used to measure pain. These can be complemented with a pain drawing.
The pain is measured and documented on each visit.
Sensory changes and location of the pain observed by the patient should be documented in a pain drawing.
Pay attention to skin temperature, vitality and sweating (the activity of sympathetic nervous system).
Neuropathic pain
Test the following senses in neurological examination: touch, sharp touch, heat, vibration, and cold, as well as the reaction to a normally painless stimulus, such as gentle stroking and light pressure of the skin.
Neurological examination Neurological Examination including tests for motor function, reflexes and cranial nerves give an idea of the location of the injury. A careful sensory examination helps in tailoring the treatment and later in assessing the treatment response.
Normal result in electroneuromyography (ENMG) Clinical Neurophysiology in Diagnostics does not exclude the possibility of peripheral neuropathy because ENMG does not provide information on the status of the small sensory fibers.
Treatment is tailored individually depending on the mechanisms of pain and the patient's characteristics by testing one method at a time and by combining treatments based on different mechanisms.
In many cases the treatment is merely symptomatic; aetiological treatment should be given immediately (e.g. relieving a compressed nerve).
Symptomatic treatment is the more effective the earlier it is begun.
Understanding the psychosocial situation of the pain patient
Nociceptive pain
Curative therapy prevents the pain from becoming chronic.
Remember the anticholinergic adverse effects and the sedative effect
Secondary drug options
The indication for the use of a capsaicin patch (8%) is peripheral neuropathic pain. The preparation is administered topically every 3 months in a unit with experience in this form of treatment. The efficacy of the treatment has been proven in postherpetic pain and in painful HIV-associated polyneuropathy.
Lidocain patch (5%) for no longer than 12 hours a day
TramadolTramadol for Neuropathic Pain is to some extent effective in the treament of pain related to diabetic neuropathy, postherpetic neuralgia and neuropathic pain associated with spinal cord injury.
Strong opioids are mainly used only when all other alternatives have been tried. The aim of opioid treatment is the alleviation of pain and the improvement of functional ability of the patient.
If the diagnosis is clear and the need for an opioid is of short duration, e.g. in an osteoporotic vertebral fracture or in intense herpes zoster pain in an elderly patient, opioid therapy can be started sooner.
The aetiology of the pain should be investigated.
Other indications
The pain is clearly alleviated with an opioid and the patient's functional capacity improves.
The patient does not have a tendency for drug abuse.
The patient does not suffer from untreated anxiety or depression.
Opioid therapy should preferably be started as the joint decision of two physicians. The implementation of the therapy should be the responsibility of only one doctor, with follow up at 1-3-month intervals. If the effect proves to be only modest and/or the adverse effects are troublesome, the opioid drug is slowly tapered off.
The administration is started with an oral preparation and the dose is raised gradually over 4-8 weeks. The drug should be taken regularly, not "as needed". In the treatment of other types of pain than cancer pain, long-acting (slow release) opioid tablets are used.
Concurrently with opioid therapy, a drug for constipation (e.g. lactulose) is started because constipation is commonly associated with opioid use and is often troublesome if not treated. A combination of oxycodone and naloxone is less constipatory than oxycodone alone. Opioid-induced constipation in patients for whom a laxative (or laxatives) have not provided adequate response can be treated with naloxegol (25 mg per day).
The patient should be well informed of the principles of medication, and he/she may increase the dose only according the previously agreed scheme.
Other methods of pain treatment are continued.
Opioids are used only to treat pain. Specific medication is used to treat anxiety and depression.
Opioid therapy for problem patients and those with chronic (but non malign) pain with strong opioids should be started in special pain management units.
The risk of abuse may be diminished by an agreement made with the patient and the local pharmacy concerning supervised drug purchasing.
Tricyclic antidepressants
Analgetic effect is independent of depression.
Lower doses are needed for pain alleviation than for reducing depression.
There is most research data on amitriptyline, which exerts an analgetic effect already in 4-5 days. Nortriptyline is as effective as amitriptyline but the adverse effects are milder.
Start with small evening doses, starting dose 10-25 mg. The drug also improves the quality of sleep.
The dose is raised by 10 mg every other day, until maximal pain relief is achieved or side effects (tiredness, dry mouth, constipation, voiding problems, orthostatic hypotension) prevent raising the dose.
The benefit can be assessed when the dose has been constant for 2 weeks.
For patients with contraindications for tricyclic drugs, pregabalin and gabapentin are the first line drugs in the treatment of neuropathic pain, except in trigeminal neuralgia.
Pregabalin and gabapentin are effective in postherpetic neuralgia and in diabetic neuropathic pain.
Pregabalin is dosed at 75 mg × 2 for a week, then at 150 mg × 2 for another week and then 300 mg × 2 if the pain is not sufficiently alleviated with the lower doses. Pregabalin has been shown to be effective in relieving central neuropathic pain in patients with spinal cord injury.
Gabapentin is started at 300 mg in the evening and the dosage is increased by 300 mg every 1-3 days up to 3 600 mg/24h if needed. The daily gabapentin dosage should be divided into three parts to ensure an even effect.
In musculosceletal pain (fibromyalgia, arthritis and arthrosis) the electrodes can be placed in the area of pain or close to it. Treatment targeted at trigger points reduces sensitivity to pressure and relaxes muscles.
In post-herpetic neuralgia the electrodes are placed above or below the sick dermatome.
In nerve injury pain the electrode is placed normally on the area of skin with a sense of touch. Areas without sense of touch do not contain sensory fibres and in the area of sensitized skin the stimulation would be intolerably strong. The electrodes can also be placed on the corresponding dermatome on the healthy side.
The treatment is most effective in the beginning. In some patients the effect wears out in long-term therapy.
Cardiac pacemaker is a contraindication.
Acupuncture
Most useful in mild nociceptive tension-type pains affecting the musculoskeletal system and in migraine. See Acupuncture.
Acupuncture may trigger autonomic reactions such as nausea, bradycardia and tiredness.
Administered through electrodes by means of a pulse generator. The electrodes are implanted into the epidural space so that the stimulation is directed at the site in the spinal cord corresponding to the pain area.
Careful patient selection, avoidance of delays, service provision in units with extensive experience and high competence, as well as incorporating spinal cord stimulation into a comprehensive multidisciplinary therapeutic approach are prerequisites for maximum utilization of this treatment mode.
Local anaesthetic injections
Series of injections of local anaesthetics have earlier been used in the management of chronic pain, but there is no evidence on their effect.
The analgetic effect is longer than the pharmacological anaesthetic effect. Epidural and spinal anaesthesias are given only by hospital pain clinics.
The injections are helpful because the analgesia normalizes the function and motor activity on the painful area (eg. resolves muscle spasms).
The principal treatment responsibility of pain patients lies with the primary health care. Specialists are consulted with when necessary. The primary health care is responsible for comprehensive follow-up care.
In specialised care, the management of pain in patients with multiple diseases and multiple problems should be carried out in cooperation between different specialties so that one unit has the coordination responsibility and the other specialties provide consultation help.
Major hospitals have pain clinics where specialists representing at least two different fields are in charge of the treatment. The clinics usually have a multidisciplinary team with an anaesthesiologist specialized in pain management, physiatrist, psychologist, psychiatrist, neurologist, orthopaedist and social worker.
The role of the psychologist is prominent when a patient tries to identify his/her own mechanisms of pain management.
There is a strong body of evidence on the effectiveness of multidisciplinary psychological treatment provided in pain clinics and based on a cognitive-behavioural approach in the treatment of severe chronic pain.
References
Mou J, Paillard F, Turnbull B et al. Qutenza (Capsaicin) 8% Patch Onset and Duration of Response and Effects of Multiple Treatments in Neuropathic Pain Patients. Clin J Pain 2013;():. [PubMed]
Finnerup NB, Attal N, Haroutounian S ym. Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. Lancet Neurol 2015;14(2):162-73. [PubMed]