Autonomic dysfunction associated with locked-in syndrome in a child

Heart Rate Variability Among Children With Acquired Brain Injury

Objective

To find evidence of autonomic imbalance and present the heart rate variability (HRV) parameters that reflect the severity of paroxysmal sympathetic hyperactivity (PSH) in children with acquired brain injury (ABI).

Methods

Thirteen children with ABI were enrolled and age- and sex-matched children with cerebral palsy were selected as the control group (n=13). The following HRV parameters were calculated: time-domain indices including the mean heart rate, standard deviation of all average R-R intervals (SDNN), root mean square of the successive differences (RMSSD), physical stress index (PSI), approximate entropy (ApEn); successive R-R interval difference (SRD), and frequency domain indices including total power (TP), high frequency (HF), low frequency (LF), normalized HF, normalized LF, and LF/HF ratio.

Results

There were significant differences between the ABI and control groups in the mean heart rate, RMSSD, PSI and all indices of the frequency domain analysis. The mean heart rate, PSI, normalized LF, and LF/HF ratio increased in the ABI group. The presence of PSH symptoms in the ABI group demonstrated a statistically significant decline of the SDNN, TP, ln TP.

Conclusion

The differences in the HRV parameters and presence of PSH symptoms are noted among ABI children compared to an age- and sex-matched control group with cerebral palsy. Within the ABI group, the presence of PSH symptoms influenced the parameters of HRV such as SDNN, TP and ln TP.

Prolonged paroxysmal sympathetic storming associated with spontaneous subarachnoid hemorrhage

Paroxysmal sympathetic storming (PSS) is a rare disorder characterized by acute onset of nonstimulated tachycardia, hypertension, tachypnea, hyperthermia, external posturing, and diaphoresis. It is most frequently associated with severe traumatic brain injuries and has been reported in intracranial tumors, hydrocephalous, severe hypoxic brain injury, and intracerebral hemorrhage. Although excessive release of catecholamine and therefore increased sympathetic activities have been reported in subarachnoid hemorrhage (SAH), there is no descriptive report of PSS primarily caused by spontaneous SAH up to date. Here, we report a case of prolonged PSS in a patient with spontaneous subarachnoid hemorrhage and consequent vasospasm. The sympathetic storming started shortly after patient was rewarmed from hypothermia protocol and symptoms responded to Labetalol, but intermittent recurrence did not resolve until 3 weeks later with treatment involving Midazolam, Fentanyl, Dexmedetomidine, Propofol, Bromocriptine, and minimizing frequency of neurological and vital checks. In conclusion, prolonged sympathetic storming can also be caused by spontaneous SAH. In this case, vasospasm might be a precipitating factor. Paralytics and hypothermia could mask the manifestations of PSS. The treatment of the refractory case will need both timely adjustment of medications and minimization of exogenous stressors or stimuli.

Paroxysmal autonomic instability with dystonia in a child: rare manifestation of an interpeduncular tuberculoma

The term 'paroxysmal autonomic instability with dystonia' was first given for a group of symptoms comprising diaphoresis, intermittent agitation, hypertension, hyperthermia, tachycardia, tachypnea, and extensor posturing. This usually occurs as a complication of severe brain injury and is infrequently reported in cases of cerebral infection. We report a 1-year-old child with intracranial tuberculoma with symptoms of paroxysmal autonomic instability with dystonia. Pertinent literature is reviewed emphasizing pathophysiology and available treatment options.

A review of paroxysmal sympathetic hyperactivity after acquired brain injury

Severe excessive autonomic overactivity occurs in a subgroup of people surviving acquired brain injury, the majority of whom show paroxysmal sympathetic and motor overactivity. Delayed recognition of paroxysmal sympathetic hyperactivity (PSH) after brain injury may increase morbidity and long-term disability. Despite its significant clinical impact, the scientific literature on this syndrome is confusing; there is no consensus on nomenclature, etiological information for diagnoses preceding the condition is poorly understood, and the evidence base underpinning our knowledge of the pathophysiology and management strategies is largely anecdotal. This systematic literature review identified 2 separate categories of paroxysmal autonomic overactivity, 1 characterized by relatively pure sympathetic overactivity and another group of disorders with mixed parasympathetic/sympathetic features. The PSH group comprised 349 reported cases, with 79.4% resulting from traumatic brain injury (TBI), 9.7% from hypoxia, and 5.4% from cerebrovascular accident. Although TBI is the dominant causative etiology, there was some suggestion that the true incidence of the condition is highest following cerebral hypoxia. In total, 31 different terms were identified for the condition. Although the most common term in the literature was dysautonomia, the consistency of sympathetic clinical features suggests that a more specific term should be used. The findings of this review suggest that PSH be adopted as a more clinically relevant and appropriate term. The review highlights major problems regarding conceptual definitions, diagnostic criteria, and nomenclature. Consensus on these issues is recommended as an essential basis for further research in the area.

Pharmacological management of Dysautonomia following traumatic brain injury

PRIMARY OBJECTIVE

To document and critically evaluate the likely effectiveness of pharmacological treatments used in a sample of patients with Dysautonomia and to link these findings to previously published literature.

RESEARCH DESIGN

Retrospective case control chart review.

METHODS AND PROCEDURES

Data were collected on age, sex and GCS matched subjects with and without Dysautonomia (35 cases and 35 controls). Data included demographic and injury details, physiological parameters, medication usage, clinical progress and rehabilitation outcome. Descriptive analyses were undertaken to characterize the timing and frequency of CNS active medications.

MAIN OUTCOMES AND RESULTS

Dysautonomic patients were significantly more likely to receive neurologically active medications. A wide variety of drugs were utilised with the most frequent being morphine/midazolam and chlorpromazine. Cessation of morphine/midazolam produced significant increases in heart rate and respiratory rate but not temperature. Chlorpromazine may have modified respiratory rate responses, but not temperature or heart rate.

CONCLUSIONS

The features of Dysautonomia are similar to a number of conditions treated as medical emergencies. Despite this, no definitive treatment paradigm exists. The best available evidence is for morphine (especially intravenously), benzodiazepines, propanolol, bromocriptine and possibly intrathecal baclofen. Barriers to improving management include the lack of a standardized nomenclature, formal definition or accepted diagnostic test. Future research needs to be conducted to improve understanding of Dysautonomia with a view to minimizing disability.

Circadian Blood Pressure and Heart Rate Changes in Patients in a Persistent Vegetative State After Traumatic Brain Injury

Alteration of autonomic nervous system regulation is known to be present in the persistent vegetative state after traumatic brain injury, termed the dysautonomic syndrome. This study assessed the circadian blood pressure and heart rate pattern and variability in the persistent vegetative state through noninvasive 24-hour ambulatory blood pressure monitoring. The study was performed in 20 subjects: 10 patients (six men and four women; mean age, 29.5+/-9.9 years; range, 19-39 years) in a vegetative state (mean, 27.3+/-5.6 days after trauma) and 10 healthy subjects as controls (six men and four women; mean age, 28+/-5.7 years; range, 29-37 years). The patients showed a blood pressure nondipper pattern; 24-hour, daytime, and nighttime values of blood pressure and heart rate were significantly higher in patients than in controls. The day-night difference in heart rate and blood pressure was also significantly lower in patients. Finally, SD and variation coefficients were significantly lower in patients. The results show changes in the variability and circadian blood pressure and heart rate patterns in persistent vegetative state patients with dysautonomic syndrome, as an expression of the sympathetic-parasympathetic activity imbalance in the control of vasomotor tone.

Gabapentin in the management of dysautonomia following severe traumatic brain injury: a case series

The pharmacological management of dysautonomia, otherwise known as autonomic storms, following acute neurological insults, is problematic and remains poorly researched. This paper presents six subjects with dysautonomia following extremely severe traumatic brain injury where gabapentin controlled paroxysmal autonomic changes and posturing in the early post-acute phase following limited success with conventional medication regimens. In two subjects, other medications were reduced or ceased without a recurrence of symptoms. It is proposed that medications that can block or minimise abnormal afferent stimuli may represent a better option for dysautonomia management than drugs which increase inhibition of efferent pathways. Potential mechanisms for these effects are discussed.

Dysautonomia after traumatic brain injury: a forgotten syndrome?

OBJECTIVES

To better establish the clinical features, natural history, clinical management, and rehabilitation implications of dysautonomia after traumatic brain injury, and to highlight difficulties with previous nomenclature.

METHODS

Retrospective file review on 35 patients with dysautonomia and 35 sex and Glasgow coma scale score matched controls. Groups were compared on injury details, CT findings, physiological indices, and evidence of infections over the first 28 days after injury, clinical progress, and rehabilitation outcome.

RESULTS

the dysautonomia group were significantly worse than the control group on all variables studied except duration of stay in intensive care, the rate of clinically significant infections found, and changes in functional independence measure (FIM) scores.

CONCLUSIONS

Dysautonomia is a distinct clinical syndrome, associated with severe diffuse axonal injury and preadmission hypoxia. It is associated with a poorer functional outcome; however, both the controls and patients with dysautonomia show a similar magnitude of improvement as measured by changes in FIM scores. It is argued that delayed recognition and treatment of dysautonomia results in a preventable increase in morbidity.