14. Neurological pain syndromes

Pain can be classified into nociceptive (tissue damage) and neuropathic (nerve damage, neurogenic). Radicular syndrome is defined as pain radiating from the neck into the shoulder and/or arm (cervical radicular syndrome, CRS) or from the back into the buttock and/or leg (lumbar radicular syndrome, LRS), accompanied by one or more symptoms or signs that are congruent with damage to a specific cervical or lumbosacral root respectively. Radicular syndrome is usually but not consistently the result of irritation or compression of a nerve root due to a prolapsed or ruptured (herniated) disc or bony compression (= compression caused by bone formation inside or just outside the vertebral canal). Radiating pain can also occur without nerve constriction being present; this is called pseudoradicular syndrome. Cervical and lumbar radicular syndromes share many similarities, but there are also clear differences in both symptomatology and treatment. There is a differential diagnosis in both CRS and LRS. In the case of very severe, especially nocturnal, pain in the shoulder, one should also consider the possibility of neuralgic amyotrophy, and in the case of severe nocturnal pain in the lumbosacral region that of neuroborreliosis. A history of malignancy, of course, points to the possibility of metastatic root compression. If cervical radicular syndrome is suspected, the physical examination is aimed at distinguishing between radicular and pseudoradicular syndrome. The indication for surgery in the case of radicular syndrome caused by a herniated disc is based primarily on clinical and not on MRI findings. Both CRS and LRS are clinical diagnoses, based mainly on the history, with physical examination having only limited value. Watchful waiting pays off, but not for everyone. Cauda equina syndrome (CES) is an indication for emergency surgery.