A case report of spontaneously healed isolated posterior inferior cerebellar artery dissection with headache alone

Abstract

Background

Isolated posterior inferior cerebellar artery dissections (iPICADs) can cause subarachnoid hemorrhages or infarctions1. The incidence of iPICAD had been thought very rare. The reports of iPICAD with stroke, however, are increasing with the progress of high resolution MRI techniques. Surgical and endovascular treatments for hemorrhagic stroke cases and medical treatments using antiplatelet or anticoagulant agents for ischemic stroke cases have been done. The treatment strategy for iPICADs with headache alone, however, is not yet established, because the reports on non-stroke iPICADs are still rare. Herein, a non-stroke iPICAD case healed spontaneously is reported and the iPICAD cases in the literature are reviewed.

Case Presentation

48 years old male, who had no past medical or traumatic history and no family history of cerebral artery dissections, felt severe right-side throbbing headache suddenly and came to OIKE clinic on the fourth day after the onset. MRI study revealed a tiny dissection like finding (pearl and string sign like) on his right proximal segment (tonsillomedullar segment) of PICA (Fig.1A). Although no intramural hematoma, double lumen finding, or intimal flap were detected by MRI study, PICA dissection could not be denied and he was observed carefully under continuous monitoring of blood pressure, heart rate and other vital signs and he was hydrated sufficiently, given analgesic anti-inflammatory agents (a non-steroid anti-inflammatory drug: Loxoprofen Sodium Hydrate 60-300mg a day). The seventh day’s MRI study showed that the diameter of the PICA was expanding more, and the patient was diagnosed with PICAD (Fig.1B). The other MRI sequences showed no infarctions or hemorrhages (Fig 1C, D). Careful conservative therapy was continued. His headache severity was assessed by numerical rating scale (NRS) every day. The inner and outer diameters of the dissected PICA were measured by MRI T1-weighted high resolution vessel wall imaging (HRVWI) (Fig.1F) and T2-weighted HRVWI (basi-parallel anatomical scanning (BPAS)) (Fig.2), respectively. Two weeks later after the onset of headache, the dissected vessel’s diameter grew up to the maximal size (Fig.2A), though the patient’s headache improved steeply on the eighth day (Fig.3). At that point, surgical or endovascular treatments for prevention of subarachnoid hemorrhage were recommended but the patient desired to continue the conservative therapy, though he was explained the risk of his dissected PICA rupture. Since the eighth day, the patient did not feel severe headache again. Four weeks later after the onset, the dissection finding on MIP images began to improve. Eight weeks later after the onset, his PICA looked like almost normal on MIP and T1-weighted HRVWI and the outer diameter was still bulging on T2-weighted HRVWI (BPAS). Finally, four months later after the onset, the outer diameter was seen almost normal in size and shape (Fig.2). The patient runs marathon races again.

Discussion

MRI studies showed no apparent intramural hematoma, double lumen, or intimal flap indicating artery dissection. PICA is a tiny vessel and it would be possible that these findings could not be detected by MRI study. Recently, the chronological changes of the affected vessels’ size and shape are considered as one criterion to diagnose cervicocephalic artery dissections including intracranial small vessels like PICA. Table 1. shows the Spontaneous Cervicocephalic Arterial Dissections Study (SCADS) criteria. According to the criteria, the patient was diagnosed with PICAD (criteria 5, 7, and 8 matched)2.

This is the first detailed report on spontaneously occurred and healed iPICAD with headache alone, followed by MRI examinations. With the progress of high resolution MRI techniques, iPICAD will be detected more frequently. Further collection and assessment of iPICAD cases will lead to determine the optimal therapeutic strategy for iPICAD.