Remission of Severe Restless Legs Syndrome and Periodic Limb Movements in Sleep after Bilateral Excision of Multiple Foot Neuromas: A Case Report

Ludwig A Lettau; Charles J Gudas; Thomas D Kaelin

Disclosures

J Med Case Reports. 2010;4(306) 

In This Article

Case Presentation

A 42-year-old Caucasian woman with a history of diabetes, depression, and human immunodeficiency virus (HIV) infection first had onset of bilateral foot tingling and numbness concomitant with an episode of acute severe pancreatitis. Over the next two years her foot dysesthesias progressed to burning discomfort, lancinating electric shock pains, and hypersensitivity. Examination by her foot specialist found physical signs indicative of bilateral Morton's neuromas, including third metatarsal head interspace tenderness and Mulder's clicks in each foot. She was given a series of neuroma injections (1 ml mixture of lidocaine, bupivacaine, methylprednisolone, dexamethasone and 4% alcohol). The injections improved the symptoms but relapses prompted bilateral third interspace neuroma excision ("initial neuroma surgery") which resulted in near-complete relief of neuropathic symptoms. After 6 months relatively mild foot dysesthesias recurred but resolved after the HIV drug stavudine was stopped.

Eighteen months after the initial neuroma surgery, fatigue, sleep difficulties, and sensorimotor symptoms typical of RLS were diagnosed in our patient. In retrospect, she had had RLS-like leg restlessness since childhood and she had noted that her leg restlessness had remitted for the 18 months since the initial neuroma surgery, which had been performed for neuropathic foot dysesthesias. Two third interspace stump neuroma injections improved leg restlessness, sleep quality and recurrent neuropathic dysesthesias. RLS and fatigue again worsened the following year but responded to pramipexole. Over the next two years she was maintained on pramipexole and intermittent neuroma injections, including several fourth interspace injections that also produced incremental improved sleep quality. However, leg restlessness, fatigue and fibromyalgia-like aches again relapsed severely and her recurrent foot dysesthesias required multiple daily doses of oxycodone-acetaminophen and tramadol. Polysomnography performed at that time showed severe PLMS and associated arousals ( Table 1 ). Her sleep specialist then increased her pramipexole dosing and prescribed oral iron for low ferritin. Over the next two months our patient remained severely symptomatic, and concern for augmentation prompted cessation of pramipexole. Additional neuroma injections were not helpful. Over the next several months she was maintained on iron, gabapentin, tramadol, oxycodone-acetaminophen and duloxetine, but continued to be severely symptomatic with respect to fatigue, leg restlessness, sleep difficulties, and bilateral foot dysesthesias. An ultrasound scan of her feet at that time (now 5 years out from the initial neuroma surgery) showed third nerve stump neuromas and bilateral neuromas of the second and fourth digital nerves. Excision of all neuromas was recommended and informed consent was obtained. The second and fourth interspace neuromas and third interspace stump neuromas (Figure 1) were then excised ("second neuroma surgery") as previously described.[8]

Figure 1.

Illustrative plantar view of the second, third, and fourth intermetatarsal space neuromas of the respective common digital branches of the medial and lateral plantar nerves of our patient's right foot (the left foot was essentially a mirror image). Short black bars indicate the points of nerve section for neuroma excision. The entrapping deep transverse metatarsal ligament lies dorsal to the neuromas and is not depicted.

Severity of evening leg restlessness, daytime fatigue, overall quality of sleep, and neuropathic forefoot numbness, burning and/or tingling, electric shock pains, and foot hypersensitivity were separately assessed with 10 cm visual analog scales, with the zero score representing no symptoms and the 10 cm score the worst imaginable severity. RLS was scored by the International RLS Rating Scale (scoring range 0 to 40 points).[9] Assessments of depressive symptomatology were performed using the Beck Depression Inventory II (scoring range 0 to 63 points, above 29 equals severe), sleep by the Pittsburgh Sleep Quality Index (scoring range 0 to 21 points, poor sleep is five or greater), and fatigue by the Fatigue Severity Scale (scoring range nine to 63 points, significant fatigue is 36 or greater), and the Multidimensional Assessment of Fatigue (scoring range 1 to 50 points, two or greater equals increasing level of fatigue). The baseline polysomnographic study was repeated six weeks after the second neuroma surgery. Each sleep study included bilateral electro-oculography, sub-mental electromyography, bilateral anterior tibialis electromyography, central and occipital electroencephalography, electrocardiographic waveform, airflow and respiratory effort assessment, oximetry, and video monitoring.

The pre-operative questionnaire and symptom scale assessments of leg restlessness, fatigue, neuropathic foot symptoms, sleep quality, and depression are shown in Table 2 . All excised neuromas were confirmed histopathologically. Despite wound pains, our patient noted marked subjective improvement in sleep quality starting from the night following surgery. She began having nightly dreams. Sustained resolution of leg restlessness and neuropathic foot dysesthesias also occurred immediately following the neuroma surgery, and she remained completely off neuropsychiatric medication as well as iron and all other drugs known to affect RLS for the next six weeks. Post-operative questionnaire and symptom assessments were performed at 18 days and polysomnography was performed at six weeks ( Table 1 and Table 2 ). At seven weeks post-operatively, she noted bilateral leg edema that was unrelated to her foot surgery, and this was associated with recurrent mild fatigue as well as some hypersensitivity and burning discomfort of her feet bothersome enough to require occasional tramadol or oxycodone in the daytime and regular gabapentin at bedtime. Leg restlessness remained in remission and good sleep quality was maintained, as reflected in her nine-week follow-up questionnaire and symptom scale responses.

By six months after the second neuroma surgery, her neuropathic dysesthesias had recurred to the point of requiring daily pregabalin dosing along with tramadol or oxycodone-acetaminophen. At six months her primary care physician also restarted citalopram for depression. At two years after the second neuroma surgery, her VAS scores for numbness and hypersensitivity exceeded the pre-operative baseline but scores for burning and/or tingling and lancinating electric shock pains remained about 50% or less of her baseline. Also after two years her RLS scores remained in the mild range and her scores for poor quality sleep and fatigue also remained much better than the baseline scores ( Table 1 ). She remained off any RLS treatment except for the RLS benefiting effects of pregabalin and intermittent oxycodone or tramadol taken for foot dysesthesias.

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