Recurrent Perimesencephalic Subarachnoid Hemorrhage After 12 Years: Missed Diagnosis, Vulnerable Anatomy, or Random Events?

Treatment and outcomes of non-aneurysmal perimesencephalic subarachnoid haemorrhage: A 5 year retrospective study in a tertiary care centre

PURPOSE

Perimesencephalic Subarachnoid Haemorrhage (PMSAH) is an uncommon type of SAH. Severity of PMSAH can be graded by the presence of blood in the Sylvian fissure. No study compares the outcomes from PMSAH with blood present or absent in the Sylvian fissure. Furthermore, the use of Nimodipine lacks evidence base in PMSAH. We investigated whether continuing Nimodipine to 21 days in PMSAH with or without blood in the Sylvian fissure made any significant difference to patient outcome.

METHODS

Retrospective study of 93 cases admitted to tertiary centre from 2016 to 2020. We compared prevalence of cases with blood in Sylvian fissure, and analysed outcomes including complications and changes to patient modified rankin scale (MRS). We also audited use of Nimodipine in these cases and analysed whether Nimodipine made any significant difference in preventing complications.

RESULTS

91 % of PMSAH were grade 1, 24 cases (26 %) had blood in the Sylvian fissure. Sylvian fissure positive (Sylvian-positive) cases were statistically significantly more likely to have higher rates of complication compared to Sylvian fissure negative (Sylvian-negative) cases. Our centre stopped Nimodipine 56 % of the time in Sylvian-negative cases and 45 % of the time in Sylvian-positive cases. There was no statistically significant difference in outcomes when Nimodipine was continued to 21 days or ceased after negative angiogram; this result extended to both Sylvian-positive and Sylvian-negative subgroups when directly comparing Sylvian-positive cases with each other and Sylvian-negative cases likewise.

DISCUSSION

Sylvian-positive cases have a significantly higher rate of complication, as well as an increase in MRS. This may be because of the inflammatory properties of haemoglobin in the subarachnoid space post-bleed. Furthermore, acknowledging the limitations of our retrospective data, we did not find a statistically significant difference in continuing Nimodipine to 21 days with relation to PMSAH outcomes in all subgroups.

Current status of perimesencephalic non-aneurysmal subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a distinctive disease, representing SAH centered in perimesencephalic cisterns, with negative angiography findings. In recent years, the number of patients with PNSAH has increased significantly; however, the knowledge of PNSAH is insufficient. Therefore, we performed a review of the literature from a PubMed search and recounted our understanding of PNSAH. In this review, we summarized that current high-resolution computed tomography angiography is an acceptable replacement for digital subtraction angiography to rule out aneurysms in PNSAH with strict criteria. The current hypothesis about the etiology of PNSAH is that there is deep vein rupture from aberrant venous anatomy and increased intracranial venous pressure. PNSAH is associated with mild symptoms and lower rates of hydrocephalus and symptomatic vasospasm. For PNSAH, conservative treatment has been the mainstream treatment. PNSAH has a benign clinical course and an excellent prognosis; in long-term follow-up, re-bleeding and death were uncommon.

Recurrent perimesencephalic nonaneurysmal subarachnoid hemorrhage within a short period of time: A case report

BACKGROUND

Spontaneous subarachnoid hemorrhage (SAH) is primarily caused by a ruptured intracranial aneurysm. Perimesencephalic nonaneurysmal SAH (PNSAH) accounts for approximately 5% of all spontaneous SAH. PNSAH displays favorable prognosis. The risk of hemorrhage recurrence is low. We report a case of PNSAH recurrence, occurring within a short time after the initial episode in a patient not receiving antithrombotic or antiplatelet drugs.

CASE SUMMARY

A 66-year-old male, without any history of recent trauma or antithrombotic/ antiplatelet medication, suffered two similar episodes of sudden onset of severe headache, nausea, and vomiting. A plain head computed tomography (CT) scan showed subarachnoid blood confined to the anterior part of the brainstem. Platelet count and coagulation function were normal. PNSAH was diagnosed by repeated head CT, magnetic resonance imaging, and cerebral angiography, none of which revealed the source of SAH. The patient was discharged without focal neurological deficits. At 6-mo follow-up, the patient had experienced no sudden onset of severe headache and presented favorable clinical outcome. Studies have reported a few patients with recurrent PNSAH, originating frequently from venous hemorrhage and conventionally associated with venous abnormalities. PNSAH recurs within a short time following the initial onset of symptoms, although the possibility of re-hemorrhage is extremely rare.

CONCLUSION

PNSAH recurrence should arouse vigilance; however, the definite source of idiopathic SAH in this case report deserves further attention.

Recurrent Bleeding After Perimesencephalic Hemorrhage: Case Report and Review of the Literature

BACKGROUND

Perimesencephalic hemorrhage (PMH), a subtype of nonaneurysmal subarachnoid hemorrhage, is characterized by a typical pattern of localized hemorrhage on head computed tomography. PMH is usually associated with a benign clinical course, and a lower incidence of complications such as vasospasm and rebleeding.

CASE DESCRIPTION

We present the cases of a man aged 28 years and a woman aged 21 years with no relevant medical history who experienced recurrent, spontaneous episodes of PMH within the course of 7 days and 29 months. No precipitating causes were identified.

CONCLUSIONS

There are only a couple of case reports of recurrent PMH, some of which were defined questionably. We review the reported cases and discuss the possible causes and long-term outcomes. Neurointerventionalists and neurosurgeons should be aware that the risk of recurrent hemorrhage of PMH does exist, although it is rather low. Even after early or late rebleeding, prognosis of PMH is excellent.

Recurrent Bleeding After Perimesencephalic Hemorrhage

BACKGROUND

Perimesencephalic hemorrhage (PMH) is a type of subarachnoid hemorrhage with excellent long-term outcomes. Only 1 well-documented case of in-hospital rebleeding after PMH is described in the literature, which occurred after initiating antithrombotic treatment because of myocardial ischemia. We describe a patient with PMH without antithrombotic treatment who had 2 episodes of recurrent bleeding on the day of ictus. To validate the radiologic findings, we conducted a case-control study. Six neuroradiologists and 2 neuroradiology fellows performed a blinded assessment of serial unenhanced head computed tomography (CT) scans of 8 patients with a perimesencephalic bleeding pattern (1 index patient, 6 patients with PMH, 1 patient with perimesencephalic bleeding pattern and basilar artery aneurysm) to investigate a potential increase in amount of subarachnoid blood.

CASE DESCRIPTION

A 56-year-old woman with a perimesencephalic bleeding pattern and negative CT angiography had 2 episodes after the onset headache with a sudden increase of the headache. Blinded assessment of serial head CT scans of 8 patients with a perimesencephalic bleeding pattern identified the patient who was clinically suspected to have 2 episodes of recurrent bleeding to have an increased amount of subarachnoid blood on 2 subsequent CT scans.

CONCLUSIONS

Recurrent bleeding after PMH may also occur in patients not treated with antithrombotics. Even after early rebleeding, the prognosis of PMH is excellent.

Should Patients Be Counseled About Possible Recurrence of Perimesencephalic Subarachnoid Hemorrhage?

BACKGROUND

Isolated perimesencephalic subarachnoid hemorrhage (pSAH) is a distinct subtype of subarachnoid hemorrhage (SAH) seen in 5% of patients with SAH, with a relatively benign natural course and good outcome compared with diffuse, aneurysmal SAH. Traditionally, the prognosis of pSAH is believed to be excellent compared with aneurysmal SAH, with no risk of recurrent hemorrhage after long-term follow-up. We describe a case of pSAH in which the patient had a recurrent perimesencephalic bleed 8 years after the initial episode. There are 5 previous reports of recurrent pSAH in existing literature.

CASE REPORT

A patient in sixth decade of life with no history of trauma presented in 2006 with acute-onset, severe headache, and "off-balance" gait. The patient was diagnosed with pSAH on the basis of computed tomography angiography and digital subtraction angiography. The patient was discharged, and follow-up computed tomography angiography over the next 2 years revealed no underlying vascular anomaly. The patient presented in 2014 with sudden onset of headache, similar to the previous episode with no new neurologic signs. Patient had repeated imaging over the succeeding 2 years, which were all negative for new blood or source of subarachnoid bleed.

REVIEW AND DISCUSSION

There are only a couple of case reports of recurrent pSAH, some of which were defined questionably. We review the reported cases and discuss the imaging results and outcome. Considering the rarity, low risks of complications, as well as the good outcome even after recurrence, we do not recommend routinely counseling patients about possibility of recurrence of pSAH.