Propriospinal myoclonus (PSM) is characterized by predominant axial jerk-like movements. To date, most of the PSM cases reported in the literature are considered to be functional (psychogenic) in origin. The “huffing and puffing sign” is a clinical clue with high diagnostic specificity for a functional etiology in gait disorders. However, this sign has not yet been described in patients with PSM. Here, we report a case of PSM of functional etiology, with coexisting gait disorder and the “huffing and puffing sign.” Our case adds to the list of clinical diagnostic clues that suggest a functional etiology of PSM.
Keywords: Functional movement disorders, huffing and puffing sign, propriospinal myoclonus
|How to cite this URL:|
Patel KS, Vijayaraghavan A, Krishnan S, Puthenveedu DK. Huffing and puffing sign in functional axial jerks with secondary gait impairment. Ann Mov Disord [Epub ahead of print] [cited 2023 Mar 23]. Available from: https://www.aomd.in/preprintarticle.asp?id=368615
| Introduction|| |
Propriospinal myoclonus (PSM) is a rare hyperkinetic movement disorder characterized by involuntary, non-rhythmic, jerk-like flexion or less commonly extension movements of the trunk, neck, hips, and knees., In general, these movements are aggravated when lying down. PSM was considered to originate from a spinal generator and spread to the caudal and rostral cord via the propriospinal pathways. PSM is denoted as primary when there is no demonstrable spinal cord pathology. Most of the cases of primary PSM are currently considered to be functional in origin and satisfy the criteria for functional movement disorders (FMD).,
The “huffing and puffing sign” or demonstration of excessive effort in the context of ambulatory difficulty is a clinical symptom described in functional gait disorders. Here, we describe a patient with phenomenological features suggestive of PSM, satisfying the criteria for FMD. Gait disorder and the “huffing and puffing sign” were observed in this patient, underscoring the functional etiology.
| Case Report|| |
A 46-year-old man presented with a 6-month history of jerk-like flexion in the trunk and abdomen, which started acutely and fluctuated in intensity. He was diagnosed with avascular necrosis of the femoral head on the left side and was advised surgical treatment, which he deferred. He was subsequently treated conservatively. The involuntary movements started when he was made to ambulate after a period of rest. The frequency of the jerks increased during sitting and walking, while the jerks partially subsided when lying down. His movements increased in frequency and severity over the next few days. In addition, he developed abnormal jerk-like movements in his shoulder and neck. The movements were absent while sleeping and were not stimulus sensitive. The movements tended to completely remit for a few days; however, they relapsed later. The patient’s neurological examination was normal, except for the presence of abnormal jerk-like flexion movements in the trunk while getting up from the supine position, sitting, standing, and walking; the movements were relatively less frequent when lying down. The jerks were random and variable and disappeared when he was engaged in tasks that distracted his attention [Video 1] [Additional file 1]. He displayed effortful and noisy breathing (huffing and puffing sign) and facial grimacing while getting up from the supine position, standing, and attempting to walk.
Magnetic resonance imaging of the spine and brain were normal. Cerebrospinal fluid study and investigations for an autoimmune or paraneoplastic etiology were negative, and his electroencephalogram was normal. Polymyography and Bereitschaftspotential could not be assessed in our patient due to technical reasons. In addition, he was found to have marked fluctuation in the intensity of symptoms during hospitalization. He was diagnosed with psychogenic PSM. Furthermore, he was evaluated by a psychiatrist and found to have depression. He was started on clonazepam and antidepressant medications. The patient continued to have a fluctuating disease course with periodic remissions and exacerbations. The severity of his symptoms during the exacerbations was reported to be approximately 50% lesser than that at the time of admission, during a telephonic review conducted 3 months later.
| Discussion|| |
PSM was initially reported by Brown et al. in 1991, and several cases have been described since then. PSM has rarely been described in patients with structural disorders of the spinal cord (secondary PSM). Most primary PSM cases have been shown to be functional, satisfying the clinical criteria for FMD. In addition, these cases have clearly demonstrated electrophysiological evidence for a functional etiology (presence of Bereitschaftspotential or incongruent polymyographic findings)., Furthermore, the term “psychogenic axial myoclonus” has been used to describe such cases.,
We could not assess polymyography or Bereitschafts potential in our patient due to technical reasons, which is a limitation of ourstudy. However, our patient had several features enabling a clinical diagnosis of FMD. His movements tended to decrease when lying down, which is incongruent with the usual pattern described in PSM. He had a variable and fluctuating disease course, with periods of complete remission in between. His symptoms started abruptly following a stressful event, and he had clear mood changes on psychiatric evaluation. In addition, distractibility was observed on clinical examination, with complete remittance of the axial flexion movements when engaged in a foot-tapping task [Video 1]. The “huffing and puffing sign” indicates the demonstration of excessive effort during walking and is considered highly specific for a functional etiology; specificity ranging from 89% to 100% has been reported., The exhibition of physical behaviors of effort disproportionate to their disability is characteristic in such patients; patients with organic gait disorders such as Parkinson’s disease, motor neuron disease, or ataxic disorders do not exhibit such demonstration of effort. Limping in our patient may be partially explained by hip pathology; however, the huffing and puffing were clearly disproportionate to the disability caused by it. In addition, the “huffing and puffing sign” has been observed in patients with other FMDs when made to stand and walk. To the best of our knowledge, this is the first report on the “huffing and puffing sign” in a patient with PSM, underscoring the functional etiology. Given its high specificity and positive predictive value for functional gait disorders, this sign should be looked for in all patients with PSM to establish a functional etiology, particularly when they report gait disturbances. Our report adds to the list of clinical diagnostic clues, suggesting the functional etiology of PSM, especially if gait is secondarily involved.
Khushboo Patel - (1) Concept and design of study, acquisition of data, analysis and interpretation of data (2) Drafting the article
Asish Vijayaraghavan – (1) Concept and design of study, acquisition of data (2) Drafting the article
Syam Krishnan- (1) Concept and design of study, analysis and interpretation of data (2) Revising the article critically for important intellectual content. (3) Final approval of the version to be published.
Divya Kalikavil Puthenveedu: (1) Concept and design of study, acquisition of data, analysis and interpretation of data (2) Revising the article critically for important intellectual content.
Ethical compliance statement
Written informed consent was taken from the patient, and permission was taken from the Head of the Institute for publication. This being a case-report, requirement for ethical clearance was waived off by the Institute in accordance with the prevailing norms.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Comprehensive Care Center for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala
Source of Support: None, Conflict of Interest: None