Related Experiment Video

Updated: Aug 15, 2026

Sub-acute Cerebral Microhemorrhages Induced by Lipopolysaccharide Injection in Rats
06:39

Sub-acute Cerebral Microhemorrhages Induced by Lipopolysaccharide Injection in Rats

Published on: October 17, 2018

6.7K

Critical illness-associated cerebral microbleeds for patients with severe COVID-19: etiologic hypotheses

François Lersy1, Thibault Willaume1, Jean-Christophe Brisset2

  • 1Hôpitaux Universitaires de Strasbourg, Service d'imagerie 2, Hôpital de Hautepierre, 1 avenue Molière, 67200, Strasbourg, France.

Journal of Neurology
|November 21, 2020
PubMed
Abstract

Insights

Severe COVID-19 patients can develop brain microhemorrhages due to hypoxemia and uremic toxins, impacting the blood-brain barrier. This study investigated the origins of these atypical hemorrhagic complications in critical illness.

Area of Science:

  • Neurology
  • Critical Care Medicine
  • Infectious Diseases

Background:

  • Brain magnetic resonance imaging (MRI) revealed widespread white matter microhemorrhages in patients during the COVID-19 outbreak.
  • These microhemorrhages represent an atypical hemorrhagic complication requiring investigation into their underlying causes.

Purpose of the Study:

  • To investigate the origin of atypical cerebral microhemorrhages observed in patients with severe COVID-19.
  • To identify potential mechanisms contributing to blood-brain barrier dysfunction in critical illness.

Main Methods:

  • A cohort of 80 patients with severe COVID-19 and acute respiratory distress syndrome (ARDS) underwent brain MRI.
  • Nineteen patients (24%) with diffuse microhemorrhages were compared to 18 COVID-19 patients with normal brain MRI.
  • Clinical data including respiratory support, D-Dimer levels, and kidney function were analyzed.

Main Results:

  • Patients with microhemorrhages experienced more severe respiratory failure, indicated by prolonged intubation and higher oxygen requirements.
  • Elevated D-Dimer levels and a trend towards more thrombotic events were observed in the microhemorrhage group.
  • More severe kidney failure, evidenced by higher creatinine levels and increased need for dialysis, was noted in patients with microhemorrhages.

Conclusions:

  • Blood-brain barrier dysfunction, driven by hypoxemia and uremic toxins, appears to be the primary mechanism for critical illness-associated cerebral microbleeds.
  • Diffuse microhemorrhages are a frequent complication in severe COVID-19 patients, highlighting the neurological impact of the disease.
Keywords:
COVID-19HypoxemiaKidney failureMRIMicrohemorrhages

More Related Videos

Evaluation of the Cognitive Performance of Hypertensive Patients with Silent Cerebrovascular Lesions07:30

Evaluation of the Cognitive Performance of Hypertensive Patients with Silent Cerebrovascular Lesions

Published on: April 23, 2021

3.3K
Pre-Chiasmatic, Single Injection of Autologous Blood to Induce Experimental Subarachnoid Hemorrhage in a Rat Model09:14

Pre-Chiasmatic, Single Injection of Autologous Blood to Induce Experimental Subarachnoid Hemorrhage in a Rat Model

Published on: June 18, 2021

2.6K

Related Concept Videos

Ischemic Stroke l: Introduction01:15

Ischemic Stroke l: Introduction

Ischemic stroke is an acute cerebrovascular condition in which blood flow to a brain region is suddenly interrupted, leading to tissue infarction. Neurons depend on continuous oxygen and glucose supply, so even brief reductions in perfusion cause energy failure, ionic imbalance, and irreversible injury. Ischemic strokes are classified into thrombotic and embolic types based on their underlying mechanisms.Thrombotic MechanismsThrombotic stroke develops when a clot forms within a cerebral artery.
Ischemic Stroke ll: Pathophysiology01:15

Ischemic Stroke ll: Pathophysiology

An ischemic stroke occurs when a cerebral blood vessel becomes obstructed, most often by a thrombus or embolus, interrupting the delivery of oxygen and glucose to brain tissue. Because neurons rely on continuous aerobic metabolism, energy failure begins within minutes of reduced perfusion. The region receiving the least blood flow becomes the infarct core, an area of irreversible cellular death. Surrounding this core lies the penumbra, a zone of hypoperfused but still viable tissue that is...
Hemorrhagic Stroke l: Introduction01:17

Hemorrhagic 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...
Hemorrhagic Stroke ll: Pathophysiology01:29

Hemorrhagic 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...
Bacterial Meningitis II: Pathophysiology01:26

Bacterial Meningitis II: Pathophysiology

Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...
Cerebral Edema ll: Pathophysiology01:22

Cerebral 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...