Painful leg and moving toes syndrome

Abstract

Painful leg and moving toes (PLMT) syndrome is a distinct clinical entity and in majority of the patients there are some underlying causes related to spinal cord, cauda equina, or peripheral neuropathy. However, some cases are cryptogenic with no identifiable underlying cause. Response to treatment is disappointing in most of the cases. We report a 60-year-old lady who presented with very severe type of painful legs and moving toes (PLMT) with no underlying cause.

Introduction

Painful legs and moving toes (PLMT) is a clinical syndrome characterized by pain in the segmental lower limb along with toe movement.[1] Movement may also be seen in feet or leg. Patient may suppress the movement for few seconds, but they appear again. Patient may have involvement of one leg or both legs as well. It has been suggested that localization is toward central generator at the spinal cord or brainstem level.[2,3] PLMT syndrome develop in a setting of spinal cord or cauda equina trauma, lumbar root lesions, and injuries to bony and soft tissues of feet and peripheralneuropathy.[3,4] Some cases are cryptogenic with no definite identifiable cause. Pain usually precedes toe movements. The altered sensory input may result in pain, abnormal efferent motor activity, or both via segmental or suprasegmental sensorimotor circuits.[4,5] PLMT is often refractory to treatment. Some patients respond to pharamacological medications such as gabapentin and benzodiazepines.

Case Report

A 60-year-old lady with no prior history of comorbid illness, presented with history of severe pain in both lower limbs for 1 year and abnormal movements of toes and feet for 6 months.

In the beginning pain occurred early in the morning on awakening and was squeezing and tickling type. Gradually over next 12 months it progressed to involve whole leg and persisted throughout the day. She used to cry intermittently because of pain as analgesics had no much effect on her pain. After 6 months of onset of pain she started to have movements of toes which were semirhythmic or nonrhythmic and occurred throughout the day. Her movements were very severe in between. She was able to partially suppress these movements by bringing both legs close to each other. Movements were also suppressed by pressing the foot against ground and during sleep. But they used to appear again after few seconds or minutes. Occasionally movements were also present in ankle and feet [Video 1]. There was no history of trauma to limb (nerve/soft tissue/muscle/cord/radicals), sleep-related disorders, paresthesia, sensory loss, motor weakness, or difficulty in walking. Her general physical examination, mini-mental scale examination (30/30), motor, sensory, and cerebellar examinations were normal. Investigations revealed high blood sugar (fasting-169 mg/dl andpostprandial-213 mg/dl) with normal glycosylated hemoglobin (5.2%). Serum electrolytes, lipid profile, vitamin B12, and thyroid profile were normal. Her sleep study (polysomnography) was normal with no evidence of periodic limb movement. Nerve conduction study including electromyography and magnetic resonance imaging (MRI) of lumbosacral spine were normal. She was started with tablet gabapentin (300 mg two times a day) on which there was some improvement in her symptoms. Tablet metformin (500 mg two times a day) was also started, on which her blood sugar was controlled.

Discussion

PLMT syndrome must be differentiated from restless leg syndrome and periodic leg movement disorder.[6] Awareness regarding this syndrome is required because these patients are often wrongly labeled as having psychogenic symptomatology.[7] Majority of the patients described in the literature are females of middle-aged group. PMLT is characterized by pain and movement which may appear together or follow each other, but in the majority of the patients pain come first and then the movement. Pain may be tearing, throbbing and cramp like, shocking, electric sensation, tingling, numbness, or simply aching in nature. Some of the patients only complain of pulling, aching, or bursting and some complain as continuous moderate to severe type of pain. There may be associated relieving or aggravating factors. Similarly, some patients complain of severe pain at the time of walking and some notice relief while they have emerged their legs in water. Many patients are labeled as cases of sciatica due to constant and nonspecific nature of the pain. Movement may be flexion, extension, abduction, adduction, dystonic, myoclonic, or sometimes rhythmic and piano-like. Sometimes movement may be intermittent also with varying degree of severity. These movements are differentiated from chorea as there is no flowing character in them. If movements are very severe, they tend to involve more proximal joints like in our patient. Our patient movements were in bilateral toes and sometimes at ankles and legs as well. In between movements were quite severe with some relief with distraction or during standing. When she was asked to suppress the movements she used to do this by bringing her both feet together. But this used to be very short lasting and movements used to reappear again after few seconds. Most common causes of PMLT reported in the literature are secondary (symptomatic) to trauma or peripheral neuropathy. But significantly large percentage of cases are cryptogenic and in one recently published large case series; 42% cases were having no identifiable underlying causes.[2] Interestingly, there was no underlying cause in our patient also. It is not clear what the pathogenesis of pain and movement is. It has been hypothesized that there may be central nervous system, spinal cord, and peripheral nervous system integration which is responsible for this interesting movement disorder. Majority of the patients are refractory to treatment and our patient also showed only mild response to tablet gabapentin. Review of literature suggests that there is no difference in treatment response in symptomatic or cryptogenic patients.[1,2]

Conclusion

Painful leg and moving toes is a rare condition, which may be symptomatic or cryptogenic. Pain usually precedes the movement. Exact cause of this entity is unclear. Response to treatment is unsatisfactory in majority of the patients.