Description

A 3-year-old healthy girl presented with intermittent spells of difficulty opening her mouth, talking and swallowing.

Episodes began 3 weeks prior without any inciting incident. Initially occurring weekly, episodes were brief and self-resolving, but had begun increasing in frequency. Symptoms were typically worse later in the day. The presenting episode started 36 hours earlier. The child was eating when her jaw unexpectedly clenched tightly, preventing her from chewing, swallowing or opening her mouth. She had no other neurological symptoms. Family denied any new exposures or trauma. She had no other systemic symptoms. Her father had severe blepharospasms in youth that resolved without treatment.

Her mouth was pursed and jaw tightly clenched (figures 1 and 2). She was drooling and appeared unable to swallow secretions or speak, though was whining and appeared frustrated. Temporomandibular joint (TMJ) was non-tender with symmetrical jaw musculature. She had fasciculations over her chin. Remainder of her examination was unremarkable.

Neck radiographs and CT were normal. MRI brain, electroencephalogram (EEG) and cerebral spinal fluid (CSF) analysis were unremarkable. No autoimmune, infectious, or paraneoplastic aetiology was identified. The patient was treated with diphenhydramine without improvement. She received lorazepam with rapid resolution of symptoms (figure 3). Symptoms returned 24 hours later, and she again got lorazepam with resolution. She was diagnosed with oromandibular dystonia and discharged on clobazam with no episodes after discharge. Clobazam was tapered after 6 months. She continues to do well.

The general paediatrician should recognise dystonia which is characterised by sustained or …