Description

A 74-year-old woman presented with a 5-year history of persistent dysaesthesia accompanied by pain in her right first to third toes. She denied urging to move her toes. The pain improved with standing, walking and plantar compression. The patient had been taking amlodipine for hypertension and pramipexole, carbamazepine and pregabalin for the pain, none of which were effective. A physical examination revealed that the movements of the second and third toes were primarily slow lateral movements (abduction and adduction) irregularly similar to 1 Hz myoclonus (figure 1, video 1). There were no other neurological findings. In addition, nerve conduction study, cranial and lumbar MRI and DaTSCAN imaging findings were not significant. The patient was diagnosed with painful legs and moving toes (PLMT) syndrome, and treatment with clonazepam provided relief.

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Figure 1

The movements of the second and third toes were primarily slow lateral movements (abduction and adduction) irregularly similar to 1 Hz myoclonus.

PLMT syndrome refers to an uncommon movement disorder characterised by limb pain accompanied by repetitive nonrhythmic digit movements.1 The movements of the toes may be flexion, extension, abduction, adduction, dystonic, myoclonic or sometimes rhythmic.2 In addition, it is characteristic that these movements are observed with slow frequency of 1–2 Hz.3 Pain exacerbating or improving features are often identified (58%), including various body positions (sitting, walking/weight bearing or bending), diurnal variations (night vs day), cold temperature and external pressure (blankets or shoes).1 PLMT syndrome is often attributed to peripheral neuropathy (28%), trauma (11%), radiculopathy (9%) or idiopathy (42%).1 The diagnosis of PLMT syndrome is usually based on the unremarkable nature of a patient’s neurological symptoms and clinical history.4 The differential diagnosis includes restless leg syndrome and akathisia, and thus pramipexole was once tried on this patient. However, restless leg syndrome usually urges to move legs and improves with motion. Akathisia also urges to move whole body.

Response to treatment of PLMT syndrome is unsatisfactory in majority of the patients.2 However, it is reported that gabapentin enacarbil, pregabalin or carbamazepine for pain and ropinirole, pramipexole or clonazepam for movements may be effective against PLMT syndrome.1 The cause of PLMT syndrome in this case was considered idiopathic and clonazepam partially treated the pain as well as digit movements.