HAVS: Diagnosis and staging by Dr. Roger Cooke
The recent editorial in Occupational Medicine by Ian Lawson identifies a number of persistent problems associated with the diagnosis and staging of…
The recent editorial in Occupational Medicine by Ian Lawson identifies a number of persistent problems associated with the diagnosis and staging of hand arm vibration syndrome (HAVS). The Stockholm scale was first published in 1987, and remains the standard method of staging the severity of the condition. Lawson identifies a number of important issues arising from the use of this scale, and notes that consistent application of the scale may not have been achieved in practice. One issue that frequently arises is the failure to differentiate between sensory symptoms arising due to nerve damage, which is sensorineural disease, and sensory symptoms that are due to cold or blanching, which are not.
In respect of the vascular component, the three criteria defined by the Court of Appeal in the case of Montracon v Whaley remain appropriate – a good history of Raynaud’s phenomenon, a history of significant exposure and exclusion of other causes. He notes that extent of whiteness is a more important indicator of severity of disease than frequency of attacks. Lawson introduces a new concept of functional impairment influencing vascular staging, and although he offers a definitive view about that, that does not reflect currently accepted definitions. He repeats the clearly defined view that cold water provocation testing is effectively obsolete.
The controversy regarding the relationship between vibration and carpal tunnel syndrome is mentioned. The need for, and role of nerve conduction tests is highlighted, and although there is a clear enthusiasm for other sensory tests such as vibrotactile thresholds and thermal aesthesiometry, it is unclear what role these will play in diagnosis, and in particular whether the results of these tests could override clinical assessment, which remains unevidenced, untested and unlikely. The potential role of these tests in distinguishing early from late 2sn HAVS is not addressed.
Ian Lawson comments on the confusion that may result from use of different sized monofilaments for assessing light touch sensation. Consistency is clearly important, but scrutiny of this technique in reports is important and may significantly influence the clinical conclusion.
This editorial is important in emphasising that use of the Stockholm scale remains relevant, but also that controversies regarding carpal tunnel syndrome, sensory testing and standardised testing have yet to be fully resolved.