Yield of diagnostic imaging in atraumatic convexity subarachnoid hemorrhage

Prognostic Factors and Imaging Strategies in Unknown Subarachnoid Hemorrhage: A Retrospective Study

Background Subarachnoid hemorrhage (SAH) without an identifiable vascular lesion on initial angiography, commonly referred to as unknown or angiogram-negative SAH, remains diagnostically and prognostically challenging. Although perimesencephalic patterns tend to be benign, diffuse hemorrhages are associated with worse outcomes. The role of repeat vascular imaging in improving diagnosis and predicting prognosis remains unclear. Objective This study aimed to identify clinical and radiological factors associated with outcomes in patients with unknown SAH and evaluate the diagnostic and prognostic value of repeat angiography. Methods We retrospectively analyzed 26 patients with spontaneous, non-traumatic SAH and negative findings on initial digital subtraction angiography (DSA). Clinical status, hemorrhage patterns, and imaging data were recorded. Outcomes were assessed at discharge using the modified Rankin Scale (mRS). Repeat angiographic modalities and timing were analyzed in relation to prognosis. Results Patients with focal hemorrhage patterns, higher Glasgow Coma Scale (GCS) scores at admission, and absence of hydrocephalus had significantly better outcomes. Repeat DSA was more frequently performed in the good outcome group, although no new vascular lesions were identified.  Conclusion Unknown SAH is generally associated with favorable outcomes, but vigilance is warranted in diffuse SAH cases. Repeat DSA may not always reveal new lesions, but it plays a valuable role in guiding clinical confidence and management decisions. Tailored imaging strategies based on clinical and radiological risk factors are recommended.

Spontaneous Non-Aneurysmal Convexity Subarachnoid Hemorrhage: A Scoping Review of Different Etiologies beyond Cerebral Amyloid Angiopathy

Spontaneous convexity subarachnoid hemorrhage (cSAH) is a vascular disease different from aneurysmal SAH in neuroimaging pattern, causes, and prognosis. Several causes might be considered in individual patients, with a limited value of the patient's age for discriminating among these causes. Cerebral amyloid angiopathy (CAA) is the most prevalent cause in people > 60 years, but reversible cerebral vasoconstriction syndrome (RCVS) has to be considered in young people. CAA gained attention in the last years, but the most known manifestation of cSAH in this context is constituted by transient focal neurological episodes (TFNEs). CAA might have an inflammatory side (CAA-related inflammation), whose diagnosis is relevant due to the efficacy of immunosuppression in resolving essudation. Other causes are hemodynamic stenosis or occlusion in extracranial and intracranial arteries, infective endocarditis (with or without intracranial infectious aneurysms), primary central nervous system angiitis, cerebral venous thrombosis, and rarer diseases. The diagnostic work-up is fundamental for an etiological diagnosis and includes neuroimaging techniques, nuclear medicine techniques, and lumbar puncture. The correct diagnosis is the first step for choosing the most effective and appropriate treatment.

Multifocal Atraumatic Convexity Subarachnoid Hemorrhage

Background

Multifocal convexity subarachnoid hemorrhage (cSAH) has generally been described in the setting of traumatic brain injury, however, it has also been reported in the absence of trauma in conditions such as with reversible cerebral vasoconstriction syndrome. We describe the clinical and radiographic characteristics of multifocal cSAH in an academic center.

Methods

We analyzed our single-center retrospective database of nontraumatic convexity subarachnoid hemorrhage from January 2015-January 2018. Convexity subarachnoid hemorrhage was defined as blood in one or more cortical sulci in the absence of trauma; patients with blood in the cisterns or Sylvian fissure were excluded. Multifocal location was defined as at least two distinct foci of hemorrhage occurring in two or more lobes. Clinical and neuroimaging data were collected.

Results

Out of 70 total patients with convexity subarachnoid hemorrhage, 13 cases were of multifocal convexity subarachnoid hemorrhage, occurring in 18.6% of all cases. The mean age was 58 years (SD = 14.7). Eleven patients were female. Seven patients had reversible cerebral vasoconstriction syndrome (RCVS)/posterior reversible encephalopathy syndrome (PRES), two had cerebral amyloid angiopathy (CAA), three had intrinsic coagulopathy, and one patient had endocarditis as the etiology of multifocal cSAH. Headache was the most common complaint, in eight (61.5%) patients.

Conclusion

Multifocal cSAH occurs in approximately 18.6% of all cSAH and can occur in the absence of trauma. In our larger cohort of all cSAH, CAA was the most common cause; however, multifocal cSAH is more commonly caused by RCVS/PRES spectrum. Clinicians should be aware that multifocal cSAH can occur in the absence of trauma, and may be a harbinger of RCVS/PRES, particularly in young patients with thunderclap headaches.

Convexal Subarachnoid Hemorrhage Caused by Infective Endocarditis in a Patient with Advanced Human Immunodeficiency Virus (HIV): The Culprits and Bystanders

BACKGROUND Convexal subarachnoid hemorrhage (cSAH), a rare form of non-aneurysmal subarachnoid hemorrhage, is confined to cerebral convexities without extension into basal cisterns or ventricles. Typical presentation includes thunderclap/progressive headache or transient focal neurological symptoms; rare manifestations include seizures, intractable vomiting, or altered mental status. Here, we report the first case of convexal subarachnoid hemorrhage and multifocal ischemic lesions caused by infective endocarditis (IE) in a treatment-naïve advanced HIV patient. CASE REPORT A 52-year-old HAART-naïve, HIV-positive, African American man presented with altered mental status, shortness of breath, nonproductive cough, and generalized weakness. His past medical history was significant for congestive heart failure, chronic obstructive pulmonary disease, and end-stage renal disease (noncompliant with hemodialysis). Head computed tomography (CT) showed an isolated sulcal hemorrhage in the mid-left frontal lobe. Fluid-attenuated inversion recovery/gradient recalled echo sequences confirmed a hemorrhage in the left-mid-frontal sulcus, and diffusion-weighted imaging revealed multifocal bilateral ischemic lesions. Transesophageal echocardiography exhibited mitral valve vegetations. Multifocal ischemic lesions and cSAH caused by infectious endocarditis were confirmed. Initiation of intravenous vancomycin and piperacillin-tazobactam allowed the patient to have resolution of his altered mental status. A head CT 5 days later revealed the resolution of cSAH. CONCLUSIONS Infective endocarditis should be considered as an underlying etiology of cSAH, especially when present with multifocal ischemic lesions. Risk factors contributing to the development of cSAH in the IE patient population should be explored in future studies. HIV has not been previously reported in this subgroup and its prevalence should be considered. The prognosis for cSAH in relation to IE is generally favorable.

Subarachnoid Hemorrhage of Unknown Cause: Distribution and Role of Imaging

Subarachnoid hemorrhage of unknown cause represents approximately 10% to 15% of nontraumatic subarachnoid hemorrhages. The key factors in determining the management strategy for a presumed nonaneurysmal subarachnoid hemorrhage are the distribution, location, and amount of subarachnoid blood. Hemorrhage distribution on computed tomography can be categorized as follows: perimesencephalic, diffuse, sulcal, and primary intraventricular. The extent of the workup required in determining the cause of hemorrhage depends on the distribution of blood. The authors review the potential causes, differential diagnoses, and acute and long-term follow-up strategies in patients with subarachnoid hemorrhage of unknown cause.

Acute convexity subarachnoid hemorrhage (cSAH) in infectious endocarditis (IE): imaging features and follow-up

AIM

To assess: (1) the prevalence of convexity subarachnoid hemorrhage (cSAH) in infective endocarditis (IE); (2) its relationship with IE features; (3) the associated lesions; (4) whether cSAH is a predictor of future hemorrhage; (5) whether cSAH could cause cortical superficial siderosis (cSS).

METHODS

We retrospectively evaluated the MRI data in 240 IE-patients: At baseline, the location of cSAH and associated lesions; at follow-up, the occurrence of new lesions and of cSS. Patients with and without cSAH were compared.

RESULTS

There were 21 cSAH-IE patients without (Group 1a) and 10 with intracranial infectious aneurysms (IIAs) (Group 1b). cSAH was revealed by headache (16.1%), confusion (9.7%), acute meningeal syndrome (3.2%) and was incidental in 71%. In most cases, the cSAH was: in the frontal (61.3%) and the parietal lobe (16.1%), unifocal, and mainly localized within a single sulcus (80.7%), appearing as a thick intrasulcal dark line on T2* in 70% of IIA patients. Valvular vegetations (87.1%, p < 0.0001), vegetations length ≥ 15 mm (58.1%, p < 0.0001) and mitral valve involvement (61.3%; p = 0.05) were significantly associated. There was no significant difference between the two groups in terms of pathogen distribution, valve characteristics and clinical expression. Associated lesions were: CMBs (77.4%), DWILs (51.6%), brain hemorrhages (16.1%) brain micro-abscesses (3.2%) meningitis (3.2%), visceral emboli (45.2%). At follow-up: no SAH recurrence or neurological event. cSS disappeared in 7/12 cases.

CONCLUSION

cSAH in IE is mostly an incidental finding but may be the telltale sign of an IIA. cSAH is not a marker of poor prognosis in non-IIA patients.