Correspondence

Shaky-Leg Syndrome and Vitamin B₁₂ Deficiency

N Engl J Med 2000; 342:981March 30, 2000

Article

To the Editor:

A 68-year-old man presented with a three-year history of trembling of the legs. The tremor began immediately after he stood and subsided when he began walking. His medical history was irrelevant to this problem. Neurologic examination showed a fine, rapid tremor of the legs that began immediately after the patient rose to the standing position and that abated on walking. Sensation of pain and heat was impaired in a stocking distribution, and the Achilles tendon reflexes were absent. Results of the rest of the examination were normal. Results of laboratory tests were remarkable only for a serum vitamin B₁₂ level of 132 ng per liter (normal range, 222 to 753). A Schilling test demon-strated malabsorption of vitamin B₁₂. A computed tomographic scan of the brain was normal. The surface electromyogram showed a 15-Hz synchronous tremor of agonist and antagonist muscles of the legs that began when the patient stood and that was absent when he was seated or lying down. Electrophysiologic studies also showed mild sensory axonal polyneuropathy. Clonazepam (1 mg per day) and cyanocobalamin (injections of 1000 μg given daily for two weeks, then weekly for two months, and once a month thereafter) provided complete relief of the tremor. Follow-up after one year showed no abnormalities. Treatment with clonazepam was then discontinued without recurrence of the tremor.

Shaky-leg syndrome, also referred to as orthostatic tremor, is an unusual movement disorder characterized by difficulty in maintaining an orthostatic position because of a leg tremor that subsides on walking or sitting.1,2 Although most cases are idiopathic, symptomatic shaky-leg syndrome has been associated with nontumoral aqueduct stenosis, relapsing polyradiculoneuropathy, head trauma, and pontine lesions.2 The origin and mechanism of shaky-leg syndrome are obscure. However, positron-emission tomographic studies have demonstrated abnormal cerebellar activation, suggesting a central origin.3 The disorder has responded to treatment with clonazepam, phenobarbital, primidone, and valproic acid.4

The association of shaky-leg syndrome with vitamin B₁₂ deficiency in our patient might have been a coincidence. However, the fact that the tremor did not recur after discontinuation of clonazepam supports this association. We think that shaky-leg syndrome was the result of disturbances in the cerebellum or related pontine structures as a result of vitamin B₁₂ deficiency. In fact, there is evidence that these structures may be affected by vitamin B₁₂ deficiency.5

Julián Benito-León, M.D., Ph.D.
Jesús Porta-Etessam, M.D.
Hospital General de Móstoles, E-28935 Madrid, Spain

5 References

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Citing Articles (4)

Citing Articles

1. 1

   A. Labiano-Fontcuberta, J. Benito-León. (2011) Carta en relación con el artículo «Importancia del estudio electromiográfico en el diagnóstico del temblor ortostático». Neurología
   CrossRef

2. 2

   S. Yagüe, M. Veciana, J. Pedro, J. Campdelacreu. (2011) Importancia del estudio electromiográfico en el diagnóstico del temblor ortostático. Réplica. Neurología
   CrossRef

3. 3

   Neeraj Kumar. (2010) Neurologic Presentations of Nutritional Deficiencies. Neurologic Clinics 28:1, 107-170
   CrossRef

4. 4

   Rick L. Smith. (2001) Evaluation of Vitamin B12 and Folate Status in the Nursing Home. Journal of the American Medical Directors Association 2:5, 230-238
   CrossRef