ACUTE BRAINSTEM INFARCT: MULTIDISCIPLINARY MANAGEMENT
Vertebro-basilar thrombosis has a high mortality rate between 75% to 86% (1). The clinical diagnosis of these patients is sometimes difficult and their medical management is not well defined. Prospective, multicenter, controlled studies have demonstrated that intravenous thrombolysis as well as intra-arterial are valid and efficacious for the treatment of acute cerebral infarct (2-3). Neuro-endovascular therapy has acquired an increasingly more active role in the treatment of brain attack (4).
We present a clinical case of acute thromboembolic occlusion of the basilar artery secondary to a traumatic dissection of the vertebral artery, which had an unusually long presentation and difficult diagnosis. The patient received a multidisciplinary medical management, which required intra-arterial thrombolysis. We discuss the clinical presentation of vertebro-basilar isquemia, the technique of intra-arterial thrombolysis, and medical management of hemodynamic factors and also the utility of brain HMPAO SPECT study in the medical management of acute brain infarct.
CLINICAL CASE:
The patient is an 18 year old male, without past medical history, transferred to Clinica Las Condes (CLC) from a small city in southern Chile called Villarica, arriving in neurologic and respiratory compromise, on mechanical ventilation. 48 hours before he had fell while playing soccer without suffering loss of consciousness. That same night he began experiencing disarthria, headache, and transient hemiparesis. The following day he was hospitalized in a local hospital. An initial brain computed tomography (CT) scan was normal. To follow, he had a generalized seizure, and his neurological state worsened and was transferred to CLC. Upon arrival to the CLC hospital, the patient was on mechanical ventilation and had been in coma for about one hour. A new CT scan only showed a possible small area of hypodensity in the pons without hemorrhage. Retrospectively, it is possible to distinguish a "hyperdense basilar artery" (Figure 1a). Immediately we performed a cerebral angiogram since we had a clinical suspicion of a possible carotid or vertebral dissection considering the history of trauma. When we began the angiogram he had been about two hours in coma, had fixed and dilated pupils, and had extensor pronation in all four extremities upon painful stimuli. In addition, he had bilateral repetitive myoclonic discharges related to brainstem ischemia.
The initial cerebral angiogram demonstrated complete occlusion of the superior segment of the basilar artery. Also, the distal segment of the right vertebral artery showed a focal stenosis and irregularity of the vessel wall, which corresponded to a dissection. Intra-arterial thrombolysis was initiated advancing a microcatheter to the occlusion at the basilar artery. A total of 700,000 units of Urokinase (UK) were infused over 30 minutes, achieving complete recanalization of the basilar artery and its principal branches. Lastly, the right vertebral artery was therapeutically occluded with GDC coils at the C2 level, just proximal to the dissection (Figure 2). Immediately post-thrombolysis, the patient once again had symmetric and reactive pupils, and localized to painful stimuli with all four extremities. A control brain CT scan showed hyperdensity in the center and left side of the pons, corresponding to a small asymptomatic hemorrhage post-thrombolysis (Figure 1b). The patient was transferred to the ICU and began hemodilution, hypervolemic, and hypertensive therapy with mean arterial pressure (MAP) of 120mm of Mercury (Hg). He was not anticoagulated.
Figure 1 (click=zoom)
Figure 2 (click= zoom)
The HMPAO brain SPECT exam performed the following day demonstrated a region of
hypoperfusion 2 and 4 standard deviations below the mean in the brainstem, more extensive
than the area of hemorrhage and infarct in the pons and left cerebral peduncle (Figure
3a). This finding was interpreted as a region of ischemic penumbra, which was treated with
hypervolemic and hypertensive therapy. A brain magnetic resonance scan showed an infarct
in most of the pons, predominantly on the left side, with only the most lateral right side
remaining normal (Figure 4). During the following days, the patient made a progressive
recovery.
Figure 3 (click =zoom)
Figure 4 (click=zoom)
A week later, when the patient was placed in the erect position for the first time during
his rehabilitation session, he had an acute neurologic decline with increased hemiparesis
and transient bilateral myoclonic discharges related to the hemodynamic effect of
orthostatic hypotension. A brain CT did not demonstrate any significant change in the size
of the brainstem infarct (Figure 1c). This event was interpreted as hemodynamic in origin,
secondary to hypoperfusion in a zone of ischemic penumbra in the pons, which was
immediately and energetically controlled with hypervolemic therapy. The patient completely
recovered of these symptoms in a few days. At day 18, he began oral intake, and had
partially recovered movements of his vocal cords. Controls with brain HMPAO SPECT scan
showed cerebellar diasquesis with hypoperfusion of the inferior right cerebellar
hemisphere. There was also increased uptake in the pons, which was interpreted as
secondary to breakdown of the blood brain barrier (Figure 3b). The rest of the study was
normal. After two months of inpatient rehabilitation, the patient made almost a complete
recovery and was discharged.
Clinical Case | Discussion | Conclusion
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