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Disability and Neck Pain – Part Two
After neck injury or generalised pain problems, the disturbances in sensory aspects may occur in the arms and legs even though there are no symptoms in these areas. Local hyperalgesia in the neck, an increased pain response to normally painful stimuli, may be due to the local nerve systems being abnormally sensitised to incoming stimuli. But these more widespread reactions can be indicative of altered processing in the central nervous system. Locally increased pain reactions in the neck can be present in whiplash and general neck pain sufferers but the more widespread sensory upsets may help distinguish whiplash from less severe neck problems.
Whiplash patients have generally higher levels of disability and pain and show more widespread pain on clinical examination. Patients with nerve root problems in the neck and those with whiplash associated disorder (WAD) both share features of sensory abnormality which may indicate that the underlying changes in the processing of pain are similar in both conditions. Another piece of evidence which may back up the role of central systems in these presentations is the occurrence of allodynia. Allodynia is the presence of pain in response to a normally non-painful stimulus such as touching, brushing or wearing clothes.
At the time of the injury the abnormal pain processing mechanisms are set up in the nervous system and the same abnormalities have been shown to be present in patients with chronic whiplash pain. Whatever the severity of the whiplash injury, all sufferers seem to have some degree of pain overreaction to inputs, with this typically settling down in two or three months in less severe cases. Those patients who suffer from chronic neck symptoms and increased levels of pain will also likely have continuing mechanical overreaction which may persist rather than reduce with time. The levels of mental distress also affect pain thresholds.
It is clear that psychological distress is a feature of patients with whiplash syndrome, with more highly distressed patients having higher levels of pain and disability. However it does not appear that the increased pain sensitivity is caused by psychological distress but that the pain and the distress may be consequences of the heightened sensitivity in the central nervous system. Apart from these findings, investigations have also shown that patients can have an exaggerated pain reaction to cold and changes in the way the blood vessels constrict.
As an overreaction to cold is part of the typical symptoms of injury to the peripheral nerves of the body this may indicate that nerve injury is present in some cases of whiplash injury. This cold overreaction is also found in neck nerve root injury, reinforcing the idea that the same underlying nerve abnormalities are found in both this condition and whiplash. In investigations of acute whiplash patients a significant percentage of neuropathic pain symptoms such as cold overreaction, burning neck pain and sudden bursts of electric shock pains have been found.
Many of the sensory findings in the neck may not easily translate into ways of managing whiplash by physiotherapy. However, if there is only local hyperalgesia in response to mechanical inputs and no other sensory abnormalities, then the local neck structures may be oversensitive due to the injury to the neck tissues. This kind of local abnormality has been shown to react favourably to physiotherapy or other manual therapies. Exercise may also reduce this type of increased nerve reactions and also improves the ways the muscles coordinate, improving the management of neck pain.
If someone has the extra features of neuropathic pain, the overreaction to cold, allodynia and more widespread sensitivity then treatment will have to be much more carefully planned. If the pain is stirred up by treatment this may increase the sensory abnormalities present and make the overall problem worse. More gentle manual and manipulative techniques may be more appropriate in these cases and physiotherapy has been shown to have some effectiveness in managing patients with whiplash.
The presence of the neuropathic symptoms such as overreacting to cold inputs means that there are typically much higher levels of disability and pain and the likelihood of physiotherapy being an effective management is uncertain. Medication for these pains is useful for about 30 percent of patients.
Jonathan Blood Smyth is the Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for physiotherapist in Blackpool visit his website.
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Filed under back pain by on Dec 22nd, 2009. 
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