Alternating hemidystonia following traumatic brain injury as an unusual presentation of paroxysmal autonomic instability with dystonia syndrome

Abstract

A 20-year-old man presented to the neurotrauma intensive care unit following blunt head injury. MRI revealed subarachnoid haemorrhage and multiple intraparenchymal haemorrhages suggesting severe brain injury. During recovery, the patient displayed intermittent episodes of alternating hemibody spasms with decerebrate/decorticate dystonic posturing. Episodes presented with autonomic dysregulation including hyperthermia, diaphoresis, tachypnoea, tachycardia and hypertension. Concern for seizure activity prompted simultaneous video monitoring and EEG testing. Results were without epileptiform activity suggesting against seizure as cause for alternating hemibody spasms. Paroxysmal autonomic instability with dystonia (PAID) was considered despite the unusual presentation. Intravenous hydromorphone was used for treatment, which relieved symptoms of autonomic dysregulation and dystonic posturing. PAID syndrome was diagnosed based on presentation with intermittent episodes of dystonia, autonomic dysregulation, absence of epileptiform activity and rapid response to opioid treatment. This case illustrates the clinical variability of this uncommon syndrome because alternating hemidystonia as main manifestation has not been previously described.

Background

Paroxysmal autonomic instability with dystonia (PAID) syndrome is a relatively uncommon complication of various central nervous system injuries. It has been reported in association with severe traumatic brain injury (TBI), brain anoxia, subarachnoid and intracranial haemorrhages (ICHs), and hydrocephalus. To the best of our knowledge, alternating hemidystonia as the main presenting symptom of PAID syndrome has never been reported in the literature.

Case presentation

A previously healthy 20-year-old man presented to the neurotrauma intensive care unit (ICU) following blunt head injury secondary to motor vehicle accident. Initially, the patient was admitted with a Glascow Coma Scale of 4. MRI revealed multiple areas of haemorrhage including subarachnoid haemorrhage and intraparenchymal haemorrhages over bi-frontal temporal lobes, right parietal lobe and left basal ganglia areas with extent into the lateral thalamus suggesting severe brain injury (figure 1). The patient's neurological status slowly improved over 20 days; however, he began to display intermittent episodes of alternating hemibody spasms with decerebrate/decorticate dystonic posturing. During these episodes there was synchronous activation of the left hemifacial muscles and left arm flexor muscles resulting in hemifacial spasms as well as unilateral arm dystonic decorticate posturing with subsequent spreading into the left hip flexor muscles. At times, a similar pattern of decorticate/decerebrate dystonic movements was noted in the right hemibody. These episodes were associated with signs of autonomic dysregulation, that is, mild hyperthermia, profuse diaphoresis, tachypnoea with respiratory rate in 40 s, tachycardia with heart rate in 140 s and hypertension with systolic blood pressure in the 160 s. The patient displayed these episodes intermittently; they occurred up to 10 times daily, lasting 20–30 s each episode.

Figure 1.

T2 fluid attenuation inversion recovery sequence showing intraparenchymal haemorrhages in the left basal ganglia, which extend into the lateral thalamus (A) and the right frontoparietal lobe (B) with surrounding cytotoxic oedema.

Investigations

MRI of the brain was performed with results as listed above (figure 1).

CT of the entire spine was performed on admission secondary to the traumatic mechanism of injury without evidence of acute osseous injury or segmental instability.

Concern for epileptic activity prompted further investigation including three EEGs. During video EEG monitoring, the episodes of hemidystonia were captured without EEG correlation (video 1).

Video 1

Sudden unilateral left arm decorticate posture followed by forceful spasms, short in duration, of the proximal arm and the left hemifacial muscles. On T1/T2 bipolar montage EEG, only muscle artefact ipsilateral to the dystonic hemibody was noted.

Differential diagnosis

The presence of autonomic dysregulation associated with spasticity/dystonia in a patient with severe TBI and ICHs could be suggestive of neuroleptic malignant syndrome, acute serotonin syndrome, autonomic dysreflexia, diencephalic seizures, or PAID syndrome. Important distinguishing factors against neuroleptic malignant syndrome and serotonin syndrome are absence of offending medications typically associated with these disorders. In addition, hyperthermia, tachycardia and hypertension manifested in intermittent episodes rather than a persistent course. Autonomic dysreflexia generally caused by spinal cord injury had effectively been ruled out by the lack of evidence on imaging during trauma evaluation.

This particular patient displayed alternating hemibody dystonia, which expands the differential diagnosis to include complex partial seizures, medication-induced acute dystonic reaction, decorticate posture due to severe TBI, or PAID syndrome. Again, offending medications that typically cause dystonia were not present in this case, thus ruling out a pharmacological cause. Decorticate posturing in the setting of TBI does not resolve with the administration of opioids, as it did in this case. Ultimately, the distinction between the remaining complex partial/diencephalic seizures and PAID syndrome was made with simultaneous video and EEG monitoring, which failed to show epileptiform activity.

Treatment

In this case presentation intravenous opioids, oral bromocriptine and propranolol were used for treatment, which relieved the autonomic dysregulation symptoms as well as the dystonic posturing. These medications are reported in the literature as possible treatments for PAID syndrome in addition to clonidine hydrochloride, lorazepam and dantrolene sodium, which were not used in this case.

Outcome and follow-up

On discharge, the patient was capable of following simple instructions and tracking the examiner intermittently. He was easily arousable with spontaneous eyes opening. No further episodes of dystonic posturing were noted while he remained on maintenance opioid therapy; however, paroxysmal mild tachycardia and hypertension persisted. The patient was discharged to an assisted living facility and a few weeks later he was transferred to another city per family request. There was no further follow-up.

Discussion

PAID syndrome presents in patients with severe brain injury primarily due to trauma or hypoxia resulting in diffuse axonal or brainstem injury.^{1 2} It may also manifest in patients with ICH, midbrain gliomas or hydrocephalus.³ The various mechanisms proposed involve dysfunction of the diencephalic autonomic centres or disruption of their connections to other brain regions leading to loss of inhibitory inputs to sympathetic feedback loops.⁴ The onset of PAID syndrome is typically delayed by 1 or 2 weeks.^{1 2} Although the pathophysiology for this remains unclear, we postulate that in our young patient, the mechanisms of cerebral autoregulation maintained autonomic homoeostasis until internal factors such as fluctuations in intracranial pressure or progression of axonal injury decompensated the initial state.

So far, only a handful of PAID syndrome cases following ICH have been reported.³ In some cases, the location of the ICH could lead to diencephalic disconnection. On the other hand, non-diencephalic locations such as the frontal lobe have also been reported to lead to PAID.⁵ The most distinctive feature of this case is the presence of intermittent and alternating hemibody dystonia. Unlike primary dystonia, where the most common clinical characteristic of the dystonic movement is either focal or segmental dystonia, patients who suffer from secondary dystonia typically present with hemidystonia. Moreover, hemidystonia is only seen in secondary causes of the disease, that is, trauma, and could show diurnal fluctuations.⁶ Secondary dystonia is caused by an abnormal functioning of the corticostriatopallidothalamocortical loop leading to enhanced excitation of the premotor cortical area.⁷ Pure cortical lesions are known to cause abnormally sustained postures. For instance, these postures are overflexed in frontal injury and overextended in parietal lesions.⁸ We postulate that the distinctive presenting symptom in this case, alternating hemidystonia, could be the result of the unique combination of direct dysfunction of the diencephalon (left thalamus) and its connections to cortical structures (right frontal lobe) due to ICHs. Nonetheless, the combination of intraparenchymal haemorrhages, subarachnoid haemorrhage and underlying mild axonal injury also represents triggers of episodic autonomic dysregulation. The exact mechanism remains unclear.

Learning points.

• Paroxysmal autonomic instability with dystonia (PAID) syndrome is an uncommon disorder that consists of paroxysms of agitation, hyperthermia, diaphoresis, hypertension, tachycardia and tachypnoea, along with hypertonia and extensor posturing.

• Early identification of PAID syndrome is important in order to start prompt treatment and to avoid unnecessary treatments for other potential differentials.

• This case illustrates the clinical variability of this uncommon syndrome because alternating hemidystonia as the primary manifestation has not been described previously.