Correspondence Address: Dr. Aditya V Nair Department of Neurology, Christian Medical College, Vellore, Tamil Nadu India
Source of Support: None, Conflict of Interest: None
The human body requires equilibrium to assume the vertical posture and balance for walking which is maintained by righting reflexes and supporting reactions, respectively. Postural movements around the ankle is responsible for maintaining forward and backward leaning in an upright posture. We report a case of postural sway and bobblehead movement following bilateral tendo-Achilles rupture.
Keywords: Tendo-Achilles – TA, astasia without abasia, disequilibrium Key Messages: Bilateral Tendo-Achilles rupture althoug a rare phenomenon, can occur following steroid intake. It can present with postural swaying.
How to cite this article: Nair AV, Prabhakar AT, Iqbal SA, Sivadasan A, Mathew V. Postural Sway and Bobblehead Movement: Unique Presentation of Bilateral Tendo-Achilles Rupture. Neurol India 2020;68:1445-6
How to cite this URL: Nair AV, Prabhakar AT, Iqbal SA, Sivadasan A, Mathew V. Postural Sway and Bobblehead Movement: Unique Presentation of Bilateral Tendo-Achilles Rupture. Neurol India [serial online] 2020 [cited 2021 May 11];68:1445-6. Available from: https://www.neurologyindia.com/text.asp?2020/68/6/1445/304100
The human body requires equilibrium to assume the vertical posture and balance for walking which is maintained by righting reflexes and supporting reactions, respectively.
According to Horak and Nashner, postural movements supporting erect stance comprise two patterns—hip and ankle pattern. Ankle pattern is responsible for maintaining forward and backward leaning in an upright posture, and this function depends on compensatory torque about the ankle against forward and backward accelerations of the body's center of gravity.
Case report of a patient presenting to Department of Neurology, Christian Medical College Vellore.
A 49-year-old lady presented with excessive swaying and head bobbing while standing for the past 3 months. She noted significant improvement in her imbalance and head movements while walking or sitting. There was no history to suggest oscillopsia/slurring of speech/gait worsening in dark.Past history was significant for type 2 diabetes mellitus for which she was on an oral hypoglycemic agent.She also revealed that she was on oral steroids (Tablet dexamethasone 16 mg/day) for a dermatological condition for the past 4 months. 3 months back she had sustained sequential nontraumatic bilateral tendo-Achilles (TA) rupture (right followed by left) over a period of 2 weeks which had preceded the onset of imbalance. There was no prior history of enthesitis/fluoroquinolone use.
Clinical examination was remarkable for bilateral TA rupture (evidenced by Thomas test) (Video labeled 3) and bilateral ankle plantar flexion weakness (MRC grade 2).The rest of the motor, sensory, and higher mental assessmentwas normal. Gait analysis in stance phase (Video 1 labelled stance) revealed astasia without abasia with bizarre anterior-posterior head-bobbing movements on assuming vertical posture, which resolved while walking/sitting. The sensory and cerebellar examination was normal.We noticed a significant improvement in postural sway and bobbing when the patient was advised to continuously step forward and backward alternately (Video 2 labeled stilts).
In summary, we report a case of postural disequilibrium and bobblehead caused by Gastro soleus dysfunction due to bilateral TA rupture. The probable cause of TA rupture was prolonged oral steroid therapy.
Hirayama et al. postulated that astasia without abasia (AA) is caused by a combination of three conditions: (a) Loss of the ankle pattern of postural movements because of decreased muscular strength and tone about the ankle joints. (b) Lack of compensatory postural movements by the hip pattern, which is dependent on sufficient strength about the hip joints. (c) Impairment of somatosensory feedback from the legs for postural stabilization.
Hachisuka et al. had postulated that gastro-soleus dysfunction in itself is sufficient to produce astasia without abasia andthat neither impairment of somatosensory feedback or disturbance of compensatory postural movements was required.
Our patients' upright Posture ankle torque is impaired due to bilateral TA rupture (satisfying criteria (a) of Hirayama) and maintenance of forward and backward tilt is impossible. She did not have any evidence of hip joint dysfunction/proximal muscle weakness/sensory dysfunction to account for the postural disequilibrium. Therefore stepping movement takes the place of postural sway when the center of gravity moves anteriorly or posteriorly.
The probable etiology for the TA rupture is attributed to prolonged oral steroid therapy. This rare presentation of TA rupture has not been previously reported in the literature and is significant for being a surgically remediable problem.
Important to recognize lower motor neuron problems leading to gait dysfunction and bizarre movement disorders
TA rupture can manifest as postural disequilibrium.
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