Myofascial pain syndrome is defined as a condition in which the patient has a number of ‘trigger points’ within taut bands of skeletal muscle or fascia (unlike the ‘tender points’ in fibromyalgia) that are painful on compression and can give rise to characteristic referred pain, tenderness and autonomic nervous system symptoms. Whether it exists as a separate entity or as a subset of fibromyalgia remains debated.
The pain is described as deep and achy and is occasionally accompanied by a sensation of burning or stinging. Myofascial pain syndrome is limited to one area or quadrant of the body.
MPS differs from fibromyalgia in the following ways:
- tender points and pain are localized rather than generalized
- referred pain occurs more frequently
- fatigue, paraesthesia, headaches, and irritable bowel occur less frequently
- MPS has a better prognosis
Aetiology
Clinical studies have shown some association between MPS and prolonged static postures, lack of exercise, sleep disturbance, and emotional stress, but clear causal factors have not yet been identified.
Identifying trigger points
Trigger points are a focus of hyper-irritability in a tissue that, when compressed are locally tender and may give rise to referred pain and sometimes to referred autonomic phenomena.
Active trigger points cause referred pain and usually have predictable patterns specific to each muscle. These trigger points are rarely located where the patient reports the pain.
Essential criteria include:
- a taut palpable band in the muscle
- exquisite spot tenderness of a nodule in a taut band
- patients recognition of pain by pressure on the trigger point
- painful limit to full passive stretch
Latent trigger points are nodular areas within a taut band of muscle that does not reproduce pain.
Treatment of trigger points
Trigger point injections: various compounds including combinations of corticosteroid and local anaesthetic are described.
Trigger point massage (acupressure) involves firm pressure over the trigger point that is slowly intensified over approximately one minute.
A technique called spray and stretch involves the use of vapo-coolant sprayed topically to the skin, while the muscle is stretched.
The use of newer techniques such as botulinum toxin is of benefit for prolonged torticollis but further studies are warranted.
Postural advice and home stretches are also recommended.