Related Experiment Video
Updated: Jun 1, 2026
09:14
Pre-Chiasmatic, Single Injection of Autologous Blood to Induce Experimental Subarachnoid Hemorrhage in a Rat Model
Published on: June 18, 2021
Recurrent idiopathic perimesencephalic subarachnoid hemorrhage
Matthew R Reynolds1, Spiros L Blackburn, Gregory J Zipfel
1Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri, USA. ReynoldsM@wudosis.wustl.edu
Journal of Neurosurgery
|June 14, 2011
Summary
Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) typically has a good prognosis. However, this case report details a rare instance of recurrent PNSAH in a single patient, suggesting rebleeding is possible.
Area of Science:
- Neurology
- Radiology
Background:
- Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a subtype of subarachnoid hemorrhage.
- It is characterized by specific CT findings and negative angiography, with a generally favorable prognosis and no reported risk of recurrent hemorrhage.
Observation:
- A 62-year-old man presented with recurrent, spontaneous episodes of PNSAH over a 5-month period.
- No identifiable precipitating causes were found, though exertional activities preceded both bleeding events.
Findings:
- This case represents the first documented instance of recurrent, idiopathic PNSAH.
- The findings challenge the established understanding of PNSAH's benign nature, indicating a potential, albeit low, risk of rebleeding.
Implications:
- While rare, recurrent PNSAH can occur, necessitating consideration of rebleeding risk.
- Further research into the etiology of idiopathic recurrent PNSAH is warranted to understand this phenomenon better.
Related Concept Videos
01:17Hemorrhagic Stroke l: Introduction
A hemorrhagic stroke is an acute neurological event that occurs when a weakened cerebral blood vessel ruptures, allowing blood to accumulate within or around the brain. The sudden release of blood forms a focal hematoma that increases intracranial pressure, displaces neural tissue, and can obstruct cerebrospinal fluid pathways. These effects may be compounded by intraventricular extension of the hemorrhage, cerebral edema, or compression of adjacent structures, all of which contribute to...
01:29Hemorrhagic Stroke ll: Pathophysiology
A hemorrhagic stroke develops when a cerebral blood vessel ruptures, allowing blood to escape into the surrounding brain tissue, as in intracerebral hemorrhage (ICH), or into the subarachnoid space, as in subarachnoid hemorrhage (SAH). Because the skull is a rigid compartment, the sudden presence of extravascular blood rapidly increases intracranial pressure and compresses adjacent neural structures, leading to immediate tissue injury and impaired cerebral perfusion.Mass Effect and Primary...
01:22Cerebral Edema ll: Pathophysiology
Vasogenic edema is a major form of cerebral edema characterized by abnormal accumulation of fluid in the brain’s extracellular space due to disruption of the blood–brain barrier (BBB). The BBB is a specialized structure composed of endothelial cells connected by tight junctions, supported by astrocytic endfeet and a basement membrane. Under normal conditions, it tightly regulates the movement of ions, proteins, and solutes between the bloodstream and brain parenchyma. When this barrier loses...
01:29Increased Intracranial Pressure ll: Pathophysiology
Increased intracranial pressure (ICP) refers to a potentially life-threatening rise in pressure inside the skull. This usually happens when there is a major change in the volume of brain tissue, blood, or cerebrospinal fluid (CSF) — the three components inside the skull. According to the Monro-Kellie doctrine, if the volume of one component increases, the volumes of the other components must decrease to maintain normal pressure. If this does not happen, ICP rises.The process often begins with...
01:26Brain Abscess l: Introduction
A brain abscess is a focal, intracerebral infection characterized by a localized collection of pus within the brain parenchyma, resulting from microbial invasion and the body’s inflammatory response. It progresses through stages: early and late cerebritis, followed by early and late capsule formation, reflecting tissue destruction, immune response, and eventual encapsulation.Etiology and PathogenesisCausative organisms vary with source and host factors, often involving polymicrobial infections,...
01:14Increased Intracranial Pressure l: Introduction
Intracranial hypertension is a sustained elevation of intracranial pressure (ICP) above 22 mm Hg. In supine adults, normal ICP is ~7–15 mm Hg.The rigid, nonexpandable cranium contains three components—brain tissue, blood, and cerebrospinal fluid (CSF)—that total ~1,700 mL in a typical adult: 1,400 mL brain (~80%), 150 mL blood (~10%), and 150 mL CSF (~10%). According to the Monro–Kellie doctrine, total intracranial volume is effectively fixed. When one component expands, CSF and venous blood...