Subarachnoid hemorrhage after transient global amnesia caused by cerebral venous congestion: case report
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Transient global amnesia is reported to be caused by cerebral venous congestion. Internal jugular venous flow reversal in particular with the Valsalva maneuver leads to cerebral venous congestion. In addition, Valsalva maneuver can also induce subarachnoid hemorrhage. Transient global amnesia and subarachnoid hemorrhage might have common a pathophysiology in cerebral venous congestion.
We report here the case of a 57-year-old woman who twice experienced convexal subarachnoid hemorrhage just after straining at stool following an episode of transient global amnesia. Digital subtraction angiography showed left temporal congestion. Left jugular vein ultrasonography revealed reflux with the Valsalva maneuver only in acute phase, indicating transient cerebral venous congestion.
Subarachnoid hemorrhage followed by transient global amnesia indicates a common factor between them. Transient venous congestion is discussed in order to explain this rare phenomenon.
KeywordsTransient global amnesia Subarachnoid hemorrhage Cerebral venous congestion Valsalva maneuver Straining
Cerebral amyloid angiopathy
Convexal subarachnoid hemorrhage
Cerebral venous thrombosis
Digital subtraction angiography
Magnetic resonance angiography
Magnetic resonance imaging
Magnetic resonance venography
Posterior reversible encephalopathy syndrome
Reversible cerebral vasoconstriction syndrome
Transient global amnesia
Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of reduced episodic memory. Several possibilities, such as cerebral ischemia and epileptic episode are suggested as the etiology of TGA, but the pathophysiology is still elusive. Internal jugular venous flow reversal that leads to cerebral venous congestion can contribute to TGA . Particularly, the Valsalva maneuver leads to internal jugular venous flow reversal in patients with TGA .
Subarachnoid hemorrhage (SAH) is mainly caused by the rupture of a cerebral aneurysm or cerebral arteriovenous malformation, but sometimes the origin cannot be detected despite detailed examinations such as digital subtraction angiography (DSA). Valsalva maneuver that leads to cerebral venous congestion can also induce SAH .
Thus, TGA and SAH might be induced by venous congestion. However, there are few reports of the relation between TGA and SAH. Although TGA as a presentation of SAH has been reported, to the best of our knowledge, SAH after TGA has been never reported. We report the case of a patient with SAH after TGA following straining at stool.
The headache steadily improved and the patient was discharged. Repeated brain imaging tests, including CT, MRI, MRA, and MRV indicated no relapse of cSAH, new lesion, reversible lesion, contraction, or thrombosis. The left internal jugular venous reflux following the Valsalva maneuver on ultrasonography disappeared four months later. Medical history and the test results are summarized in the Additional file 1.
Discussion and Conclusion
Secondary TGA is likely to be caused by stroke, epilepsy, migraine, or abnormal cerebral venous reflux. CA-1 subfield of the hippocampus is related to TGA, and is affected by hypoxemia-induced metabolic stress, β-amyloid-induced neurotoxicity, and ischemia . However, the predominant hypothesis is that TGA most commonly occurs due to abnormal cerebral venous drainage from the temporal lobes [1, 5]. Increased intrathoracic pressure, such as that caused by Valsalva maneuver, could trigger retrograde venous flow in patients with valve incompetence in the internal jugular veins. The resulting venous congestion would preferentially affect the function of the medial temporal lobes, thus triggering the anterograde amnesia . In this case, DSA showed congestion in the temporal lobe.
Internal jugular venous flow reversal and internal jugular vein valve incompetency can contribute to TGA. Although not all patients with TGA show internal jugular venous flow reversal or internal jugular vein valve incompetency, this phenomenon is more common in patients with TGA than in controls or patients with transient ischemic attack . Since the Valsalva maneuver causes internal jugular venous flow reversal in patients with TGA , in this case, it was not clear whether the patient performed the Valsalva maneuver before the onset of TGA. A high-density spot was found in her left hippocampus on DWI and left internal jugular venous flow reversal was noted with ultrasonography only during the acute phase. This was in agreement with a diagnosis of TGA.
However, a high-density spot on DWI also indicated ischemic stroke. TGA may be associated with right-to-left shunt, such as patent foramen ovale [6, 7]. We did not perform the right-to-left shunt study using transesophageal echocardiography or transcranial doppler. There were no abnormal findings such as thrombosis on leg venous ultrasonography and transthoracic echocardiography. Pulmonary arteriovenous fistula was ruled out by chest-body CT. We could not exclude paradoxical embolism, which is limitation, though results of our tests suggested that the patient was unlikely to have paradoxical embolism.
According to previous reports, TGA may not be associated with ischemic stroke. TGA patients have a much lower stroke risk than TIA patients . On the other hand, the relation between TGA and SAH is not well documented . Most studies reported amnesia as a presentation of SAH, i.e., secondary TGA is caused by SAH. To our knowledge, SAH after TGA has never been reported. Because TGA is a benign disease and recurrences are infrequent, the follow-up of the patients with TGA is stopped early. Thus, the relationship between TGA and SAH might be overlooked.
It is reported that cSAH may be caused by cerebral amyloid angiopathy (CAA), reversible cerebral vasoconstriction syndrome (RCVS), posterior reversible encephalopathy syndrome (PRES), or cerebral venous thrombosis (CVT) [10, 11]. In addition, patients ≤60 years frequently present a severe headache of abrupt onset with arterial narrowing on conventional angiograms, presumptively diagnosed with a primary vasoconstriction syndrome, while patients >60 years usually have temporary sensory or motor symptoms and are likely to present leukoaraiosis and/or hemispheric microbleeds and superficial siderosis on brain MRI, compatible with amyloid angiopathy . In this case, CAA, RCVS, PRES, and CVT were not detected.
The Valsalva maneuver can induce SAH . It is unlikely that the patient had headaches twice by chance just after straining at stool. Four months after admission, internal jugular venous flow reversal was not observed after the Valsalva maneuver and the patient did not have a headache, which suggested that transient venous congestion occurred at the onset of cSAH. Internal jugular venous flow reversal is seen in normal individuals, although it does not always lead to the development of TGA . In this case, transient internal jugular venous flow reversal induced transient aggravation of venous congestion, which might have been pathological.
For SAH caused by CVT, the leading hypothesis is that secondary venous hypertension may trigger rupture of fragile superficial veins. The superficial veins have thin walls, which contain no smooth muscle fibers or no valves. Given obstructed drainage, these veins bridging the subarachnoid and subdural spaces can store blood and regulate cerebral venous stream . This phenomenon may occur in TGA patients with internal jugular venous flow reversal due to venous congestion. Patients with TGA are reported to have hypoplastic venous sinus . In this case, the left transverse sinus was hypoplastic. The frontal convexal veins might have been hypoplastic and fragile, which resulted in cSAH.
It is unclear why the patient had a hemorrhage twice in the right side. Left cerebral blood could not have avoided flowing into superior sagittal sinus due to left temporal congestion, which might have resulted in secondary right cerebral hemisphere congestion. Although we attempted to prove it, perfusion-weighted imaging did not reveal distinct increased blood flow in right convexal frontal lobe. Given congestion only on the surface of brain, it is difficult to prove the congestion. Further studies are required to test this hypothesis.
Few persons develop TGA or SAH, although venous congestion is common. Disease onset might be affected by venous structural deficits, such as vein valve incompetency and vessel wall vulnerability. Transient venous congestion may also contribute to disease onset.
The mechanism of the onset in this case was unique, as straining was the trigger. TGA may be attributed to abnormal venous flow. Therefore, TGA and cSAH might share the same precipitating factor, namely transient venous congestion.
The authors received no financial support for the research, authorship and/or publication of this article.
Availability of data and materials
All the data supporting our findings are provided within the manuscript.
YM examined, evaluated the patient. YM and MN designed the study and wrote the draft. YM and MN contributed to the acquisition and analysis of the clinical data and the interpretation of the clinical data. TW, HM, EI and SW participated in the design of the case-report and helped to draft the manuscript. All authors read and approved the final manuscript.
Ethics approval and consent to participate
All procedures performed in studies involving human participants were approved by the Ethical Committee of Suiseikai Kajikawa Hospital and were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Consent for publication
Written informed consent was obtained from the patient for publication of this case report and any accompanying data.
The authors declare that they have no competing interests.
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