What are the implications of diffusion restriction due to Intraventricular Hemorrhage (IVH)?

From the Guidelines

Diffusion restriction from IVH is a critical finding that requires prompt management to improve patient outcomes, and the current evidence supports the use of external ventricular drainage (EVD) with intraventricular thrombolysis (IVT) as a safe and effective treatment to improve survival in patients with clinical hydrocephalus and reduced level of consciousness. This recommendation is based on the most recent and highest quality study, the 2022 guideline for the management of patients with spontaneous intracerebral hemorrhage from the American Heart Association/American Stroke Association 1.

The diffusion restriction pattern in IVH typically appears as hyperintense signal on diffusion-weighted imaging (DWI) and hypointense signal on apparent diffusion coefficient (ADC) maps within the ventricular system. This occurs because blood products, particularly in the acute to early subacute phase (first few days after hemorrhage), contain deoxyhemoglobin and intracellular methemoglobin that restrict water molecule movement. The diffusion restriction pattern in IVH follows the distribution of blood within the ventricles and may change over time as blood products evolve.

Key points to consider in the management of IVH include:

• The use of EVD to treat intracranial hypertension and remove blood products improves survival 1
• The addition of thrombolytic irrigation with alteplase or urokinase hastens intraventricular clot removal and results in further mortality reduction 1
• The current recommendations are based primarily on data from the largest RCT of intraventricular thrombolysis (IVT; CLEAR III [Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage]) 1
• Other interventions studied for removing large volumes of IVH and reducing permanent shunt dependence include controlled lumbar drainage combined with IVT and targeted intraventricular neuroendoscopy 1

In terms of specific treatment, the evidence suggests that EVD with IVT is a safe and effective treatment for patients with IVH, particularly those with clinical hydrocephalus and reduced level of consciousness. The use of thrombolytic agents, such as alteplase or urokinase, can help to hasten intraventricular clot removal and improve patient outcomes. However, the benefit of EVD to improve functional outcomes is uncertain, and further research is needed to fully understand the effects of this treatment.

Overall, the management of IVH requires a comprehensive approach that takes into account the patient's clinical presentation, imaging findings, and underlying medical conditions. By using EVD with IVT, clinicians can help to improve patient outcomes and reduce the risk of complications associated with IVH.

From the Research

Diffusion Restriction from IVH

• Diffusion restriction from intraventricular hemorrhage (IVH) is a complex phenomenon that can lead to various clinical outcomes 2.
• IVH can cause acute hydrocephalus by impairing cerebrospinal fluid dynamics, and the toxicity of accumulated hematoma in the ventricles might also influence the hydrocephalus and cause poor outcomes 3.
• The use of thrombolytic agents can significantly reduce both the duration of ventricular drainage and mortality compared to external ventricular drainage alone, but the functional outcome is not improved in patients with IVH 3, 4.
• Diffusion-restricting lesions can be seen in patients with IVH, especially in patients with intracranial hemorrhage, and the etiology and clinical significance of these lesions remain unknown and warrant further research 2.

Management of IVH

• Prompt management of patients with IVH is required to stabilize the clinical status of patients upon admission, and further advanced management is crucial to reduce the morbidity and mortality associated with intraventricular bleeding 5.
• External ventricular drainage (EVD) is a key factor in the treatment of IVH, but it is associated with risks and complications, and intraventricular fibrinolysis (IVF) has been proposed to improve clinical outcome and reduce complications of EVD treatment 4.
• The management of elevated intracranial pressure (ICP) is dependent on the underlying cause, and medical options include head of bed elevation, IV mannitol, hypertonic saline, transient hyperventilation, barbiturates, and surgical options include CSF drainage and decompression of a surgical lesion 6.

Clinical Outcomes

• IVH is associated with high mortality and morbidity, and several prognostic factors have been identified, such as IVH volume, number of ventricles with blood, involvement of fourth ventricle, baseline Glasgow Coma Scale score, and hydrocephalus 5.
• The use of IVF can promote hematoma clearance, decrease mortality, improve good functional outcomes, and reduce the rate of catheter occlusion 4.
• Further research is needed to investigate medical and surgical options for the treatment of raised ICP and to establish the effectiveness of endoscopic techniques in the management of IVH 3, 6.