Spontaneous remission of dropped head syndrome following short-term bed rest in acute encephalopathy: a case report.

Abstract

Background: Dropped head syndrome is commonly observed in neurodegenerative disorders such as dementia with Lewy bodies. Its underlying causes include neck extensor myopathy and cervical dystonia. However, spontaneous remission of dropped head syndrome is extremely rare.

Case presentation: A 70-year-old woman initially presented with a dropped head. One year after her first visit, she developed gait disturbance, bilateral hand bradykinesia, and rigidity of the trunk and all four limbs. Levodopa had a limited effect on both the dropped head and parkinsonism, and was eventually discontinued due to visual hallucinations. Two years and three months after the initial visit, her Mini-Mental State Examination score declined to 22/30, and she was ultimately diagnosed with dementia with Lewy bodies. Three years and two months after the initial visit, she experienced decreased consciousness due to acute encephalopathy associated with cellulitis. After 10 days of bed rest, her consciousness normalized, and she gradually resumed sitting and standing. Remarkably, the dropped head, previously present even before the encephalopathy, was no longer observed in either posture. The remission of dropped head syndrome persisted for over a year.

Conclusion: Sustained supine positioning for 10 days may have induced prolonged relaxation of the anterior cervical muscles, functioning as a form of "prolonged sensory trick," thereby modulating the sensorimotor cortex and contributing to the remission of dystonic anterocollis. Furthermore, the restoration of neck extensor muscle strength may have followed the resolution of dystonic anterocollis. This case may offer insight into the mechanisms underlying spontaneous remission in dropped head syndrome.