Reply to “Orthostatic tremor secondary to recreational use of solvents”

Dear Editor:

It was with great interest that we read the case report by Drs Cruz Tabuenca, Camacho Velásquez, Rivero Sanz, Sánchez Valiente, and López del Val of a patient with orthostatic tremor secondary to the recreational use of solvents.¹ The case is a very interesting contribution to the literature on nervous system lesions caused by exposure to volatile organic compounds. However, we believe that the authors could have further explored the pathophysiology and genesis of this type of tremor. Therefore, with a view to enriching the discussion, we provide some suggestions regarding certain omissions in that article, particularly the pathogenesis of tremor, which could help us understand the onset of the patient's symptoms.

Orthostatic tremor is a very rare movement disorder, clinically characterised by a feeling of instability or imminent fall when standing up, which disappears or improves when walking and is absent when seated or in the decubitus position.^2–5 The pathophysiogenesis of orthostatic tremor is unknown, although there is mounting evidence suggesting the presence of a central oscillator.^3,4 This oscillator would be modulated by a neuronal network consisting of subcortical (cerebellum, basal ganglia) and cortical structures. Although the specific anatomical location of this central oscillator is also unknown, it has been suggested that it may be located in the posterior fossa.^3,4 For example, different pontine,⁶ mesencephalic,⁷ or cerebellar⁸ lesions have been associated with symptomatic orthostatic tremor. In this case, the lesions observed were mainly located in the posterior fossa, i.e., in areas associated with the pathogenesis of orthostatic tremor. We therefore believe that these lesions may be related to the pathogenesis of the orthostatic tremor observed in this patient.

In any case, we wish to congratulate the authors on their excellent study and look forward to meeting them at a medical conference to further discuss these topics in person.