Movement disorders, dystonia and chorea: Case

Summary and immediate impression

This boy has status dystonicus, the most severe form of dystonia, and it is a life-threatening emergency. The escalating, painful, sustained dystonic spasms over 12 hours, the tachycardia, the reduced chest wall excursion, and the creatine kinase of 18,000 units per litre marking significant rhabdomyolysis, together demand immediate triage to intensive care. He is non-verbal, so the assessment must read his pain and distress as real, and the two-day fever and reduced intake point to an infective precipitant. [6]

The first hour — resuscitation and the hunt for the precipitant

My first priority is the airway and breathing, because chest wall involvement in status dystonicus can cause respiratory failure. I secure the airway, provide supplemental oxygen, monitor the respiratory rate and oxygen saturation, and prepare for ventilatory support. I establish intravenous access and start aggressive fluid resuscitation to protect the kidneys from the rhabdomyolysis shown by the creatine kinase of 18,000 units per litre, checking renal function and urine myoglobin and aiming for a generous urine output. I control his pain, because dystonia hurts and uncontrolled pain feeds the spasm, and I place him on cardiac and haemodynamic monitoring. [7]

I hunt for the precipitant, because removing the trigger is part of the cure. The two-day fever and reduced intake point to an infective trigger, so I screen for sepsis, send blood and urine cultures, examine the chest, and look for a source. In a non-verbal child with cerebral palsy I have a low threshold for treating pain and for investigating a hip, because a worsening dystonia in cerebral palsy is a hip or a pain problem until proven otherwise, and I check for constipation, urinary infection, dental disease, and gastro-oesophageal reflux. I confirm that his home baclofen and trihexyphenidyl have not been missed or changed. [7]

The escalation ladder

I deploy temporising measures while preparing for escalation. I give a benzodiazepine such as diazepam or midazolam to settle the spasm and buy time, and I continue and up-titrate his enteral anti-dystonia drugs, trihexyphenidyl and baclofen, with consideration of tetrabenazine for severe dystonia. If the spasms will not settle, I sedate, paralyse, and ventilate him in intensive care while the dystonia-directed therapy takes effect. For refractory status dystonicus, I give early consideration to intrathecal baclofen or deep brain stimulation, and I involve the paediatric neurology, neurosurgery, and intensive care teams early. [6][7]

The contrasting emergency — the acute dystonic reaction

The examiner may contrast this with the acute dystonic reaction, which is the other movement disorder emergency and the common iatrogenic cause. A child who develops an oculogyric crisis, torticollis, and oromandibular spasm hours after a dopamine-blocking drug such as metoclopramide or an antipsychotic has an acute dystonic reaction, and the correct response is an immediate anticholinergic such as benztropine, procyclidine, or diphenhydramine given intramuscularly or intravenously, with the causative drug withheld. The reaction reverses within minutes, and this is why metoclopramide is avoided in this boy and in any child with a movement disorder. [10]

Prognosis, counselling, and the long-term plan

I would tell the family that status dystonicus is life-threatening but that the escalation plan is designed to bring it under control, and I would be honest that recovery from a severe episode can be prolonged and that he will need close monitoring in intensive care. Once the acute episode settles, I review his long-term dystonia management, which rests on the oral ladder of trihexyphenidyl and baclofen, with botulinum toxin for focal problem areas and consideration of intrathecal baclofen or deep brain stimulation for severe generalised dystonia, individualised to his function and comfort. The Cochrane evidence for trihexyphenidyl is of low certainty, so the family is counselled that the expectation is modest and that the choice is individualised. [8][9]

At discharge I provide the family with a written dystonia action plan that lists the early signs of worsening dystonia and the threshold for returning, and a clear safety-net for escalation, because the family is the first responder when a chronic dystonia worsens toward status dystonicus. I arrange paediatric neurology and rehabilitation follow-up, with attention to his posture, hip surveillance, pain control, nutrition, and communication, and I involve the allied health team. [6]

Marking domains

• Diagnosis and reasoning: recognises status dystonicus, identifies the rhabdomyolysis risk, and hunts for the precipitant. [6]
• Management — acute: secures the airway and breathing, hydrates aggressively for rhabdomyolysis, controls pain, and escalates anti-dystonia therapy. [7]
• Management — definitive: runs the escalation ladder through sedation and ventilation to intrathecal baclofen or deep brain stimulation, and avoids dopamine-blocking drugs. [6][10]
• Communication: counsels the family honestly, provides a written dystonia action plan, and arranges coordinated multidisciplinary follow-up. [9]