Dr Rainer Freynhagen
PD-Q: A screening tool to identify neuropathic components in pain patients
Every fifth European is suffering chronic pain, according to the recent ‘Pain in Europe Survey’. However, there are pains and other kinds of pain, as particularly seen in patients with neuropathic pain.
At the German Congress for Orthopaedics and Trauma Surgery new diagnostic and treatment methods were described that might promote better pain therapy.
Usually doctors classify pain according to an accepted system that is based on the type and extent of the prevailing dysfunctions. ‘However, it is not the dysfunctions but the underlying pathophysiological mechanisms the pain is based on which are decisive,’ said neurologist and psychologist Professor Thomas R Tölle MD, who is Head of the Pain Surgery at the Neurological Clinic in Munich’s Technical University. Pain, he said, can be traced to nociceptive and neuropathic mechanisms. ‘Neuropathic pain development, caused by lesions or dysfunctions of peripheral nerves or central nerve tracts, takes a severe course: Based on inflammatory processes, the patients develop physiological changes that lead to hyper-sensitised, peripheral, spinal and supraspinal signal processing. Patients with neuropathic pain require specialist and intensive treatment.’
At the DRK Pain Centre in Mainz, neuropathic pain is currently being documented from comprehensive physical examinations, laboratory tests, electrodiagnostics, imaging, biopsies and quantitative sensory testing (QST). Professor Hans-Raimund Casser MD, the Centre’s medical director, said: ‘We have to intervene in these inflammatory processes as early as possible to prevent nociceptor sprouting and chronification of the pain. But even achieving a precise diagnosis is difficult and complex, because we don’t need to detect the symptoms but the nerve damage.’
‘Up to now we have not had any method to diagnose neuropathic pain at an early stage on a large scale,’ added pain therapist Rainer Freynhagen MD. With a research associate and team at the Anaesthesiology Clinic at Düsseldorf University Hospital, 47,000 patients have been examined in a project called painDETECT. ‘We discovered that patients with neuropathic pain complain about long and severe periods of pain with relevant loss in functional efficiency. Moreover, characteristically they tend to suffer from particularly pronounced comorbidities, such as sleep disorders, panic attacks and anxiety or depression.’
Based on the collected data the researchers developed a painDETECT questionnaire (PD-Q) – a list of questions that can be completed by patients and their doctors within a few minutes. ‘The painDETECT questionnaire in no way replaces regular diagnostic procedures, but it is an important aid because the calculated score has a high significance as to the prevalence of neuropathic pain components,’ explained Dr Freynhagen, who this year was awarded the 1st promotional prize for pain research.
The questionnaire, which is now available in fourteen languages, paves the way for early, individually adapted medication. Good treatment results are currently being achieved with Pregabalin (LYRICA, Pfizer). Licensed since September 2006 for the treatment of central neuropathic pain, Pregabalin modulates a calcium influx into the nerve cell and leads to a reduced release of excitatory transmitters. It not only weakens the course of the pain and its intensity but also eases mental and somatic symptoms, such as sleep disorders and anxiety. ‘I admit that we do not yet know all of the pathomechanisms. But we are getting very close with our methods and have achieved significant therapeutic success,’ Prof. Tölle concluded.
This article was published on 11/14/2007