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|Year : 2022 | Volume
| Issue : 4 | Page : 1625-1628
Trans-cranial Doppler Flow Characteristics of a Child with Paroxysmal Sympathetic Hyper-activity: A Preliminary Report
Debajyoti Datta, Vipin Chandran, Sumit Bansal, Rabi Narayan Sahu
Department of Neurosurgery, All India Institute of Medical Sciences, Bhubaneswar, Orissa, India
|Date of Submission||12-Jan-2022|
|Date of Decision||12-Jun-2022|
|Date of Acceptance||16-Jun-2022|
|Date of Web Publication||30-Aug-2022|
Department of Neurosurgery, Room No. 12, All India Institute of Medical Sciences, Bhubaneswar, Orissa - 751 019
Source of Support: None, Conflict of Interest: None
Background: Paroxysmal sympathetic hyper-activity (PSH) is a syndrome characterized by excessive activity of the sympathetic nervous system. The cerebrovascular flow dynamics during the episodes of paroxysmal hyper-activity has also not been clearly examined in the literature.
Case History: A 12-year-old boy with operated exophytic brain stem pilocytic astrocytoma was diagnosed with paroxysmal sympathetic hyper-activity. The trans-cranial Doppler flow characteristics of the bilateral middle cerebral artery and anterior cerebral artery are described in this report.
Conclusion: The diagnosis of PSH requires an index of suspicion on the part of the clinician. The episodes of sympathetic hyper-activity are associated with significant changes in physiologic parameters in the patients including changes in cerebrovascular flow dynamics.
Keywords: Brain tumor, paroxysmal sympathetic hyper-activity, trans-cranial Doppler
Key Message: Paroxysmal sympathetic hyper-activity (PSH) is a syndrome characterized by excessive activity of the sympathetic nervous system. Herein, the authors are reporting trans-cranial Doppler flow characteristics of cerebrovascular flow dynamics in a child with PSH.
|How to cite this article:|
Datta D, Chandran V, Bansal S, Sahu RN. Trans-cranial Doppler Flow Characteristics of a Child with Paroxysmal Sympathetic Hyper-activity: A Preliminary Report. Neurol India 2022;70:1625-8
|How to cite this URL:|
Datta D, Chandran V, Bansal S, Sahu RN. Trans-cranial Doppler Flow Characteristics of a Child with Paroxysmal Sympathetic Hyper-activity: A Preliminary Report. Neurol India [serial online] 2022 [cited 2022 Oct 2];70:1625-8. Available from: https://www.neurologyindia.com/text.asp?2022/70/4/1625/355139
Paroxysmal sympathetic hyper-activity (PSH) is a syndrome characterized by excessive activity of the sympathetic nervous system. It has been defined as a “Syndrome recognized in a sub-group of survivors of severe acquired brain injury, of simultaneous, paroxysmal transient increases in sympathetic (elevated heart rate, blood pressure, respiratory rate, temperature, sweating) and motor posturing activity.” Severe acquired brain injury may be because of traumatic brain injury (TBI), anoxic/hypoxic brain injury, tumors, stroke, infections, or other undetermined causes. TBI is the most common underlying cause of PSH. The pathophysiology behind the development of PSH has not been clearly elucidated. Disconnection between the cortical inhibitory centers and the diencephalic, brain stem, and spinal sympathetic centers is the most common presumed cause. The cerebrovascular flow dynamics during the episodes of paroxysmal hyper-activity has also not been clearly examined in the literature. Herein, we report the trans-cranial Doppler flow characteristics of the bilateral middle cerebral artery (MCA) and anterior cerebral artery (ACA) in a child with PSH.
| » Case History|| |
A 12-year-old boy with exophytic brain stem pilocytic astrocytoma was operated through mid-line sub-occipital craniotomy, and gross total excision of tumor was performed [Figure 1]. The post-operative period was uneventful, except that he required tracheostomy because of lower cranial nerve paresis and was discharged under satisfactory conditions after 3 weeks of hospital stay. Two weeks later, the child was brought to casualty with altered sensorium and respiratory distress. He also had two episodes of focal seizures with secondary generalization which were controlled with anti-epileptics. The patient improved under general conditions after giving supportive treatment. However, it was noted that the patient was having paroxysmal episodes of bilateral tonic limb posturing associated with tachycardia, tachypnea, raised blood pressure (BP), and excessive sweating during the paroxysms. Electro-encephalography was performed during the paroxysms to exclude non-convulsive seizures/atypical seizures. His cerebrospinal fluid, blood, and urine cultures were negative with a serum procalcitonin value <0.05 ng/ml excluding any ongoing sepsis. Deep venous thrombosis/pulmonary embolism was also excluded. He was diagnosed as a case of paroxysmal sympathetic hyper-activity using the Paroxysmal Sympathetic Hyper-activity – Assessment Measure (PSH-AM) with the pediatric clinical features scale. He was started on clonidine, labetalol, and gabapentin with intermittent propofol and had gradual response to therapy with the PSH-AM score decreasing to 17 from 25.
|Figure 1: Pre-operative NCCT head (axial image) showing an exophytic hypo-dense lesion in the pons and mid-brain (a), T2 Flair magnetic resonance imaging image showing a hypo-intense lesion with areas of hyper-intensity dorso-laterally in the pons and mid-brain (b), post-operative contrast-enhanced computed tomography scan showing complete excision of lesion (c), and NCCT head (axial image) after re-admission showing no residual/recurrent tumor (d)|
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Trans-cranial Doppler (TCD) (Delica Transcranial Doppler Ultrasound System, Model – EMS – 9PB) was performed during the episodes of paroxysms and intervening normal periods along with measurement of pulse, BP, and respiratory rate [Table 1]. Transcranial Doppler measurements included the measurement of peak velocity, mean velocity, and pulsatility index (PI) of bilateral MCA and ACA [Figure 2]. Multiple TCD measurements were taken during the episodes of sympathetic hyper-activity and in the intervening normal periods. Student T test was used to test for any significant differences. The mean pulse rate during the episodes of sympathetic hyper-activity was 117.18 and 64.09 during intervals. Similarly, the BP and respiratory rate were also elevated during the attacks. There were significant differences between the mean left MCA, left ACA, and right MCA during the episodes of sympathetic hyper-activity with the PI being significantly less during the episodes of hyper-activity. The left ACA mean and peak velocity and the right MCA mean velocity were also significantly different when measured during the paroxysmal episodes compared to normal intervals [Table 2]. The patient responded favorably to given treatment with a decrease in frequency of paroxysmal episodes and regaining a Glasgow Coma Scale (GCS) of E4VtM6.
|Table 1: Pulse, systolic and diastolic blood pressure (SBP, DBP), and respiratory rate (RR) during paroxysms of sympathetic hyper-activity and in between paroxysms|
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|Figure 2: Trans-cranial Doppler tracings: Right MCA in between paroxysms (a), right MCA during the episode of paroxysmal sympathetic hyper-activity (b), left MCA in between paroxysms (c), and left MCA during the episode of paroxysmal sympathetic hyper-activity (d)|
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|Table 2: Mean velocity, peak velocity, and PI of bilateral MCA and ACA during paroxysms of sympathetic hyper-activity and in between paroxysms|
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PSH leads to increased metabolic disturbance and neurological deterioration leading to increased mortality following TBI., Although PSH has been most commonly associated with TBI, PSH in cases of brain stem tumors and posterior fossa tumors compressing the mid-brain and brain stem have been rarely reported., Disconnection theory and excitatory/inhibitory ratio (EIR) theory are two widely accepted theories explaining the pathogenesis of PSH. Disconnection theory states that acquired severe brain injury leads to a disconnection between cerebral inhibitory centers of sympathetic discharge and the brain stem and spinal cord sympathetic centers. This loss of inhibition leads to excessive sympathetic activity. The EIR theory suggests a two-step process of pathogenesis of PSH. The first step is the disconnection between cortical inhibitory and brain stem/spinal cord sympathetic centers which causes increased sympathetic activity. However, after some time, the inhibitory processes recover and hence the paroxysmal nature of the disorder.,
In the present case, the PI of left MCA, left ACA, and right MCA had significantly decreased during the episodes of sympathetic hyper-activity. PI, also known as Gosling's pulsatility index is defined as the difference between peak systolic velocity (PSV) and end-diastolic velocity (EDV) divided by mean velocity (PI = [PSV-EDV]/MV). PI is taken as a measure of peripheral resistance. Bellnar et al. showed that PI is correlated with the intra-cranial pressure (ICP); that is, an increased intra-cranial pressure causes increased PI. They derived a formula for ICP from PI, which is ICP = (10.93 X PI) – 1.28.
During the episodes of sympathetic hyper-activity, there was associated hyper-ventilation as noted in [Table 1] of the study. This leads to CO2 washout as has been noted in our study. CO2 washout leads to vasoconstriction and fall in ICP, directly explaining the increase in arterial flow velocities and a decrease in PI as PI is linearly correlated with ICP. This hypothesis can be tested by comparing the pCO2 values during an episode of sympathetic hyper-activity and during the normal interval. It is to be noted that stellate ganglion block (chemical or surgical), resulting in decreased sympathetic activity, leads to increased cerebral blood flow; conversely, sympathetic over-activity will lead to decreased blood flow. However, the regulation of cerebral blood flow is controlled by a complex interaction between pH, pCO2 and sympathetic activity, although pCO2 is the predominant factor.
We believe that the changes in PI during the paroxysmal episodes are mediated through the effect of decreased pCO2, resulting in a decreased ICP instead of a direct effect of the sympathetic hyper-activity on the cerebral vessels. The time-dependent changes in PI during and between the paroxysms suggest association with the paroxysms.
The diagnosis of PSH is clinical and is made using the PSH-AM clinical criteria as used in our study. To the best of our knowledge, TCD has not been used to diagnose PSH in the literature. Hence, our study was undertaken to explore the cerebrovascular flow dynamics during the paroxysms of PSH using the TCD modality. The PSH-AM has two parts, the Clinical Feature Scale (CFS) and the Diagnosis Likelihood Tool (DLT). A total score of ≥17 is a probable diagnosis of PSH, 8–16 indicates possible PSH, and if the score is <8, then PSH is unlikely. Diagnosis of PSH requires exclusion of other conditions such as seizures, sepsis, and deep vein thrombosis/pulmonary embolism, which may have similar constellation of symptoms.
The management of PSH is usually multi-modal with non-selective beta blockers (such as propranolol) or selective alpha and beta blockers (such as metoprolol and labetalol), which are first-line drugs along with central alpha2 agonist clonidine. Opioids such as morphine and fentanyl are also effective in preventing and treating attacks. Gabapentin and bromocriptine are second-line drugs along with baclofen, dexmedetomidine, propofol, and benzodiazepines.
| » Conclusion|| |
The diagnosis of PSH requires an index of suspicion on the part of the clinician. The episodes of sympathetic hyper-activity are associated with significant changes in physiologic parameters in the patients including changes in cerebrovascular flow dynamics. Further studies should be undertaken to fully elucidate the changes in cerebrovascular flow during episodes of sympathetic hyper-activity and its role in the pathogenesis of this disorder.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]