Subarachnoid Hemorrhage Confirmed by Magnetic Resonance Imaging in a Patient with Brain Death owing to Hypoxic Encephalopathy Following Suicide by Hanging.

Although true subarachnoid hemorrhage (SAH) is an atypical complication owing to suicide by hanging, pseudo-SAH can often develop because of hypoxic encephalopathy. Therefore, differentiating pseudo-SAH from true SAH using brain computed tomography (CT) is often challenging. In Japan, an individual's cause of brain death must be determined to be eligible for organ donation, regardless of whether true SAH is involved or not. Herein, we report a case of SAH confirmed by magnetic resonance imaging (MRI) in a patient with brain death owing to hypoxic encephalopathy following suicide by hanging. A 48-year-old man attempted suicide by hanging. Upon arrival at the hospital, he developed pulseless electrical activity with apnea. Although spontaneous circulation returned within a few minutes of his arrival, spontaneous breathing did not recover. The patient was in deep comatose state without response to pain stimulation, brainstem reflexes, or electrical activities on an electroencephalogram. Consequently, the patient met diagnostic criteria for clinical brain death based on the Japanese organ transplantation law. Brain CT revealed global hypoxic injury and high density in the basal cisterns and subarachnoid space. Brain MR T2*-weighted imaging revealed low intensity at the left Sylvian fissure underlying the hematoma. These findings indicated brain death owing to hypoxic encephalopathy following hanging, and incidental true SAH was confirmed by MRI. Donor surgery and organ transplantation were performed. Spontaneous SAH can often develop secondary to hanging, and brain MRI can effectively determine whether the cause of brain death involves true SAH.

Pseudo Subarachnoid Hemorrhage Sign in Bacterial Meningitis in a Patient Presenting With Acute Ischemic Stroke: A Novel Radiological Clue to Rapid Diagnosis.

Pseudo subarachnoid hemorrhage (SAH) is an entity defined when characteristic computed tomography (CT) findings of SAH are seen without evidence of hemorrhage on MRI, autopsy, or cerebrospinal fluid analysis. This imaging phenomenon has been reported in association with multiple clinical settings including diffuse cerebral edema, hypoxic-ischemic injury, post percutaneous coronary intervention, and the focus of our report, acute bacterial meningitis. The mechanisms leading to this finding are poorly understood. Current hypotheses explaining this pattern vary widely depending on the associated pathology. In this report, we present a case of pseudo SAH associated with bacterial meningitis and a literature review on the causes, neuroimaging findings, and mechanisms associated with pseudo SAH. We discuss dual energy CT as a possible tool for differentiating pseudo SAH from true SAH. We analyze the timing of imaging studies and the role timing plays in the presentation of the pseudo SAH sign. We conclude that the extravasation of iodine contrast into the subarachnoid space can mimic SAH on CT. Ultimately, our case adds to the growing body of evidence that clinicians should be aware of acute bacterial meningitis as a potential mimic of SAH on CT.

Coccidioidal meningitis with multiple aneurysms presenting with pseudo-subarachnoid hemorrhage: illustrative case.

BACKGROUND: Coccidioidomycosis is a primarily self-limiting fungal disease endemic to the western United States and South America. However, severe disseminated infection can occur. The authors report a severe case of coccidioidal meningitis that appeared to be a subarachnoid hemorrhage (SAH) on initial inspection. OBSERVATIONS: A man in his early 40s was diagnosed with coccidioidal pneumonia after presenting with pulmonary symptoms. After meningeal spread characterized by declining mental status and hydrocephalus, coccidioidal meningitis was diagnosed. The uniquely difficult aspect of this case was the deceptive appearance of SAH due to the presence of multiple aneurysms and blood draining from the patient's external ventricular drain. LESSONS: Coccidioidal infection likely led to the formation of multiple intracranial aneurysms in this patient. Although few reports exist of coccidioidal meningitis progressing to aneurysm formation, patients should be closely monitored for this complication because outcomes are poor. The presence of basal cistern hyperdensities from a coccidioidal infection mimicking SAH makes interpreting imaging difficult. Surgical management of SAH can be considered safe and viable, especially when the index of suspicion is high, such as in the presence of multiple aneurysms. Even if it is unclear whether aneurysmal rupture has occurred, prompt treatment is advisable.

Pseudo-subarachnoid hemorrhage and gadolinium encephalopathy following lumbar epidural steroid injection.

Patients with imaging findings concerning for subarachnoid hemorrhage, however, with no evidence of hemorrhage following autopsy or cerebrospinal fluid testing are diagnosed with having pseudo-subarachnoid hemorrhage. A 73-year-old female presented to the emergency department with altered mental status one day after undergoing a lumbar epidural steroid injection at an outside hospital; a noncontrast computed tomography scan of the head revealed evidence of diffuse hyperdensity within the subarachnoid space concerning for subarachnoid hemorrhage. The patient underwent magnetic resonance imaging which demonstrated diffuse opacification of the cerebrospinal fluid spaces with gadolinium and the diagnoses of pseudo-subarachnoid hemorrhage and gadolinium encephalopathy were made. The combination of the neurologic symptoms related to gadolinium encephalopathy and the radiographic findings of pseudo-subarachnoid hemorrhage can create a clinical presentation nearly identical to ruptured aneurysmal subarachnoid hemorrhage. Patient history, magnetic resonance imaging findings, and temporal changes in computed tomography provide vital tools in establishing a diagnosis of pseudo-subarachnoid hemorrhage, especially after an iatrogenic intrathecal contrast administration.

Spontaneous Intracranial Hypotension with a Reversible Splenial Lesion after Swimming.

Spontaneous intracranial hypotension (SIH) is an important cause of headache mainly associated with spinal cerebrospinal fluid leakage. We herein report the case of a 51-year-old man who developed SIH after swimming. Brain magnetic resonance imaging (MRI) showed a transient high-intensity lesion in the splenium of the corpus callosum (SCC), in addition to bilateral subdural hematomas (SDH) and pseudo-subarachnoid hemorrhage on brain computed tomography. The splenial lesion disappeared and SDH improved after an epidural blood patch. This case emphasizes that transient SCC lesions could coexist with SIH and that SIH should be considered in the differential diagnosis of SCC lesions.

Correlation between hyperhemoglobinemia and pseudosubarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) is a severe cerebrovascular condition. Some cases present with typical signs of SAH on head computed tomography (CT), whereas other cases have a condition known as pseudo-SAH, with no bleeding actually present. In our clinical experience, we noted that cases of hyperhemoglobinemia often also had pseudo-SAH. Here we investigated the relationship between hyperhemoglobinemia and pseudo-SAH and explored the underlying mechanism. METHODS: We retrospectively collected data for patients who were treated for hyperhemoglobinemia in our hospital and had available brain CT scans. An age-matched control group of patients with normal hemoglobin levels was used to compare the incidence of pseudo-SAH between individuals with elevated versus normal hemoglobin levels. Spearman correlation and logistic regression analyses were performed to identify correlations between pseudo-SAH and hemoglobin level as well as gender, history of chronic obstructive pulmonary disease, and smoking history. RESULTS: The incidence of pseudo-SAH was significantly higher in hyperhemoglobinemia group than in the control group (12.5% vs. 1.6%, respectively, P < 0.001), and within the hyperhemoglobinemia group, it was significantly higher among those with a hemoglobin value ≥210 g/L than among those with a hemoglobin value <210 g/L (29.2% vs. 8.8%, respectively, P < 0.001). Spearman correlation analysis and logistic regression analysis showed a significant correlation between pseudo-SAH and hyperhemoglobinemia but no significant correlation between pseudo-SAH and gender, COPD, or smoking history. CONCLUSION: Hyperhemoglobinemia may be a contributing factor to pseudo-SAH. Clinicians should be aware of this phenomenon and be careful to distinguish pseudo-SAH from SAH, particularly in patients with hyperhemoglobinemia.

Extended Pseudo-Subarachnoid Hemorrhage Post-Percutaneous Coronary Intervention.

We report the case of an extended pseudo-subarachnoid hemorrhage (PSAH) related to contrast intracerebral diffusion from blood-brain barrier breakdown on periprocedural percutaneous coronary intervention right corticofrontal ischemic stroke. PSAH is a rare and complex phenomenon, and it is important to differentiate PSAH from subarachnoid hemorrhage to avoid inappropriate treatment with potentially severe consequences. (Level of Difficulty: Beginner.).

Bilateral Chronic Subdural Hematoma Presenting with Pseudo-Subarachnoid Hemorrhage Sign on Computed Tomography.

BACKGROUND: On rare occasions, cisterns are demonstrated as high-density areas on computed tomography (CT) and misdiagnosed with subarachnoid hemorrhage (SAH). This false-positive finding is called pseudo-SAH. PATIENTS AND METHODS: From April 2014 to August 2018, a total of 161 patients with chronic subdural hematoma (CSDH) were treated in our hospital. For these cases, the existence of a pseudo-SAH sign on CT was retrospectively examined. RESULTS: One patient with bilateral CSDH showed pseudo-SAH and a further examination to evaluate vascular abnormalities causing true SAH was necessary. In three patients, the Sylvian fissures were demonstrated as high-density areas due to an atherosclerotic middle cerebral artery; however, the condition was not misdiagnosed with SAH. CONCLUSION: In cases of CSDH, there is a possibility that CT demonstrates a pseudo-SAH sign. In such cases, close examinations to exclude true SAH are mandatory.

Pseudo-Subarachnoid Hemorrhage; Chronic Subdural Hematoma with an Unruptured Aneurysm Mistaken for Subarachnoid Hemorrhage.

Subarachnoid hemorrhage (SAH) usually occurs due to aneurysmal rupture of intracranial arteries and its typical computed tomography (CT) findings are increased attenuation of cisterns and subarachnoid spaces. However, several CT findings mimicking SAH are feasible in diverse conditions. They are so-called as pseudo-SAH, and this report is a case of pseudo-SAH which is misdiagnosed as aneurysm rupture accompanied by bilateral chronic subdural hematoma (cSDH). A 42-year-old male with severe headache visited our institute. Non-contrast brain CT images showed increased attenuation on basal cistern, and cSDH on both fronto-temporo-parietal convexity with midline shifting. Trans-femoral cerebral angiography was done and we confirmed small aneurysm at right M1 portion of middle cerebral artery. Under diagnosis of SAH, we planned an operation in order to clip aneurysmal neck and remove cSDH. cSDH was removed as planned, however, there was no SAH and we also couldn't find the rupture point of aneurysm. Serial follow-up CT showed mild cumulative cSDH recurrence, but the patient was tolerant and had no neurologic deficit during hospitalization. We have checked the patient via out-patient department for 6 months, there are no significant changes in volume and density of cSDH and the patient also have no neurologic complications.

Development of pseudo-subarachnoid hemorrhage secondary to hypoxic-ischemic injury due to bleeding pulmonary arterio-venous malformation.

BACKGROUND: The computed tomography (CT) finding of a pseudo-subarachnoid hemorrhage (SAH) may lead the treating physician into a diagnostic dilemma. We present a case of a pseudo-SAH in a patient with post-resuscitative encephalopathy, secondary to a newly diagnosed bleeding pulmonary arterio-venous malformation (AVM). CASE PRESENTATION: A 19-year-old female presented acutely with massive hemoptysis. Cardiopulmonary resuscitation (CPR) followed, and the patient was subsequently intubated for airway protection with intensive care unit (ICU) admission. Urgent CT angiography of the thorax showed a bleeding pulmonary AVM, with evidence of hemothorax. Non-contrasted cranial CT initially revealed cerebral edema. Day 3 post admission, repeat cranial CT showed worsening cerebral edema, with evidence of pseudo-SAH. Patient passed away the next day. CONCLUSIONS: Pseudo-SAH, if present, carries a poor prognosis. It should be recognized as a potential CT finding in patients with severe cerebral edema, due to various causes. The diagnosis is vital, to avoid wrongful treatment institution, as well as determination of cause of death.

Nonaneurysmal "Pseudo-Subarachnoid Hemorrhage" Computed Tomography Patterns: Challenges in an Acute Decision-Making Heuristics.

BACKGROUND: Acute aneurysmal subarachnoid hemorrhage (SAH) is a medical and neurosurgical emergency from ruptured brain aneurysm. Aneurysmal SAH is identified on brain computed tomography (CT) as increased density of basal cisterns and subarachnoid spaces from acute blood products. Aneurysmal SAH-like pattern on CT appears as an optical illusion effect of hypodense brain parenchyma and/or hyperdense surrounding cerebral cisterns and blood vessels termed as "pseudo-subarachnoid hemorrhage" (pseudo-SAH). METHODS: We reviewed clinical, laboratory, and radiographic data of all SAH diagnoses between January 2013 and January 2018, and found subsets of nonaneurysmal SAH, originally suspected to be aneurysmal in origin. We performed a National Library of Medicine search methodology using terms "subarachnoid hemorrhage," "pseudo," and "non-aneurysmal subarachnoid hemorrhage" singly and in combination to understand the sensitivity, specificity, and precision of pseudo-SAH. RESULTS: Over 5 years, 230 SAH cases were referred to our tertiary academic center and only 7 (3%) met the definition of pseudo-SAH. Searching the National Library of Medicine using subarachnoid hemorrhage yielded 27,402 results. When subarachnoid hemorrhage and pseudo were combined, this yielded 70 results and sensitivity was 50% (n = 35). Similarly, search precision was relatively low (26%) as only 18 results fit the clinical description similar to the 7 cases discussed in our series. CONCLUSIONS: Aneurysmal SAH pattern on CT is distinct from nonaneurysmal and pseudo-SAH patterns. The origin of pseudo-SAH terminology appears mostly tied to comatose cardiac arrest patients with diffuse dark brain Hounsfield units and cerebral edema, and is a potential imaging pitfall in acute medical decision-making.

"Pseudo-subarachnoid hemorrhage sign" on early brain computed tomography in out-of-hospital cardiac arrest survivors receiving targeted temperature management.

PURPOSE: Newly updated guidelines suggest brain computed tomography for out-of-hospital cardiac arrest survivors to identify a neurologic cardiac arrest cause. We hypothesized that the "pseudo-subarachnoid hemorrhage" (p-SAH) sign in cardiac arrest survivors is associated with poor outcome. MATERIALS AND METHODS: We retrospectively evaluated the registries of 2 tertiary hospitals, identifying 836 adult (≥18 years) patients achieving return of spontaneous circulation after out-of-hospital cardiac arrest. Among them, 398 patients with brain computed tomography within 6 hours after return of spontaneous circulation and received targeted temperature management from 2009 to 2014 were included. Clinical characteristics and outcomes of patients with and without p-SAH were compared. RESULTS: The prevalence of p-SAH sign was 8.0%. The p-SAH group more frequently had asystole as first rhythm and nonwitnessed arrest, predominantly resulting from asphyxia (56.3%). Targeted temperature management characteristics were not different between groups, although the p-SAH cohort had worse neurologic outcomes at discharge (100% vs 67.2%; P < .001). Pseudo-subarachnoid hemorrhage had 11.5% sensitivity, 100% specificity, 100% positive predictive value, and 32.8% negative predictive value for poor neurologic outcome. CONCLUSIONS: Pseudo-subarachnoid hemorrhage sign might be one of the simple methods to identify poor neurologic outcome early. However, further prospective studies will be needed to clarify the clinical implication of the p-SAH sign.

Pseudo-subarachnoid hemorrhage in a patient with hypoxic encephalopathy.

The authors report an unusual case of diffuse subarachnoid hemorrhage on brain computed tomography (CT) scan in a patient with post-resuscitation anoxic encephalopathy. A 42-year-old woman suffered both respiratory and cardiac arrest, associated with hypoxic encephalopathy, which occurred during a visit to our gynecology clinic. CT examination was performed the next day, which revealed a hyperdensity in the basal cisterns with a diffuse cerebral edema. Lumbar puncture was applied for diagnosis. No yellow coloration or red cells were observed in the cerebrospinal fluid. Nineteen days after treatment, the CT examination revealed features of a subarachnoid hemorrhage with a significantly increased cerebral edema. The patient died two months later. This clinical case illustrates that hypoxic encephalopathy can mimic diffuse subarachnoid hemorrhage on CT scan.

Pseudo-subarachnoid hemorrhage: a potential imaging pitfall associated with spontaneous intracranial hypotension.

OBJECTIVE: (1) To determine the frequency of CT mimics of subarachnoid hemorrhage (SAH) in a large cohort of subjects with spontaneous intracranial hypotension (SIH). (2) To emphasize the distinctive radiologic features of SIH. PATIENTS AND METHODS: CT scans of 95 subjects with SIH were retrieved and reviewed to search for findings of pseudo-SAH (CT mimics of SAH in the absence of blood). RESULTS: Pseudo-SAH radiologic findings (increased attenuation in the basilar cisterns, sylvian fissures, or along the tentorium) were detected on CT scans of 10 of the 95 SIH subjects. However, on MRI scans, these subjects exhibited the typical SIH abnormalities (diffuse pachymeningeal enhancement and brain sagging with obliteration of basilar cisterns). CONCLUSIONS: In the emergency room, SIH should be considered in the differential diagnosis between SAH and pseudo-SAH. Although SIH and SAH can share some radiologic features, SIH has distinctive MRI and CT findings. Their recognition should obviate the need for more invasive procedures (e.g., cerebral angiography) to definitely rule out SAH and an aneurismal source of bleeding.

Therapeutic and prognostic implications of subarachnoid hemorrhage in patients who suffered cardiopulmonary arrest and underwent cardiopulmonary resuscitation during an emergency room stay.

OBJECTIVE: Aneurysmal subarachnoid hemorrhage (SAH) is a well-known cause of sudden cardio-pulmonary arrest (CPA). Even after successful cardio-pulmonary resuscitation (CPR), the prognosis of patients following an aneurysmal SAH presenting with CPA remains dismal. However, there have been anecdotal reports of good outcomes with appropriate interventions. Pseudo-SAH resulting from marked elevation of intracranial pressure (ICP) after CPR, can mimic SAH in head computed tomographic (CT) scan. Such manifestations hamper resuscitation or delay appropriate neurosurgical management. This study assessed incidence and clinical characteristics of SAH-CPR or pseudo-SAH-CPR patients among non-traumatic CPA-CPR patients, and investigated their therapeutic and prognostic implication. METHODS: During the 5-year observation period, 63 non-traumatic coma patients with CT evidence of high attenuation areas in the basal cistern who suffered arrest and underwent CPR during initial resuscitation in the emergency room, were reviewed retrospectively. They were divided into two groups according to the imaging pattern: true-SAH vs. pseudo-SAH, and then true-SAH group were further divided into two groups according to the CT acquisition time: brain CT before arrest vs. brain CT after arrest. Demographic, clinical, and CT data were assessed, and the primary outcome was measured using the 30-day Glasgow Outcome Scale (GOS) score, and the final outcome was evaluated at the end of 3 months post-ictus. RESULTS: When compared with pseudo-SAH (n=28) patients, true-SAH (n=35) patients showed a higher Hounsfield unit values in the affected area, earlier CT acquisition time before CPR, more survivors beyond 3 months (all p<0.05); however, the 30-day survival rate was not significantly different. Of the true-SAH patients, ruptured intracranial aneurysms were found in eight patients, and definite intervention was administered in four patients. When SAH patients were categorized according to the temporal relationship with CPR, the group of 24 patients undergoing CT scan before CPR showed a lower frequency of intraventricular hemorrhage, but showed a higher chance of surgical treatment and survival at 30 days and 3 months compared to the group undergoing CT scan after CPR. CONCLUSION: The overall survival between true-SAH and pseudo-SAH group was different significantly. Administering definite treatment for a ruptured aneurysm in instances of true SAH could save patients, albeit infrequently. A Prompt CT scan could guarantee recognition of high-density area, blood in the ventricle, and subsequent identification of the ruptured aneurysm, altogether preventing re-bleeding and warranting further systemic resuscitation.