Adductor laryngeal breathing dystonia in NBIA treated with botulinum toxin-A
This 10-year-old boy, product of non-consanguineous marriage, with normal birth history and milestones, presented at 7 years of age with stiff legs with scissoring of lower limbs and frequent falls while walking. Over next 2 years, he had abnormal episodic posturing in form of flexion at elbows, hyperextension of neck, lower limbs, and sometimes trunk. He had severe jaw-opening dystonia and anarthia for last 6 months. For last 3 months, he had episodes of severe inspiratory stridor lasting 1-3 minutes, which was absent during sleep. He was almost gasping during these episodes, with corresponding fall in SPO2 of as low as 65% (noted at the time of admission to this hospital), that would relieve temporarily after a deep breath at the end of long inspiratory stridor. There was no past history of preceding febrile illness, jaundice, drug or toxic exposure, or positive family history.\nOn examination, vitals were stable, except tachycardia. During inspiratory stridor, his SPO2 was very low. He had severe generalized dystonia involving flexion at elbows, wrist, and all interphalangeal joints, hyperextension of knee, dorsiflexon of ankle, hyperextension of neck, severe jaw-opening dystonia, and inspiratory stridor (ALBD) every 2-5 minutes. Frequency and severity was more during activity. His Barke-Fahn Marsden (BFM) dystonia severity score was 96 / 120. He was conscious and was fully oriented and following verbal commands. His all limbs were spastic with exaggerated reflexes with extensor planters. Ophthalmological examination excluded retinitis pigmentosa and Kayser-Fleischer ring. His other routine biochemical tests including liver function test, serum ceruloplasmin, serum copper, and 24-hour urinary copper were normal. No acanthocytes were seen in peripheral blood smear examination. T2W images of brain showed hypointense bilateral globus pallidi with central hyperintensity, suggestive of typical ‘Eye of Tiger’ sign []. Videolaryngo-scopy showed paradoxical closure of vocal cords during inspiratory phase, suggestive of ALBD.\nPatient was planned for botulinum toxin-A therapy treatment for ALBD. Pre-procedural preparation included pre-anesthetic evaluation for general anesthesia (in case required to intubate this patient, if would develop severe vocal cord spasm during procedure), availability of anesthetist with preparation for intubation, and ventilatory support. In awake state, bilateral thyroarytenoid muscles were injected with 3 IU of botulinum toxin (Botox, Allergan) on each side, under electromyography guidance using Myoject needle (Teva, USA). Effect of botulinum toxin started within hours, with complete disappearance of stridor in next 7 days. The effect of this injection lasted for next 18 months, and he needed another injection recently. There was no adverse effect during or following botulinum toxin injection. Two months after botulinum toxin injection, he underwent bilateral GPi deep brain stimulation surgery, and at 6 months follow-up, his BFM score had improved to 54/120 (improvement of 56%), but gradually his improvement has reduced at 18 months follow-up.