Intracerebral haemorrhage

An intracerebral haemorrhage, or intraparenchymal cerebral haemorrhage, is a subset of an intracranial haemorrhage as well as of stroke, defined by the acute accumulation of blood within the brain parenchyma.

This article concerns non-traumatic intracerebral haemorrhages; traumatic haemorrhagic cerebral contusions are discussed separately.

Terminology

By convention, intracerebral haemorrhage refers to macroscopically visible, recent haemorrhages. In contrast, cerebral microhaemorrhages are discussed separately.

Clinical presentation

An intracerebral haemorrhage presents similarly to an ischaemic stroke, with with a rapid onset of focal neurological deficit, which is determined by the area of the brain that is involved. Compared to ischaemic stroke, there is more likely to be a decreased conscious state ¹¹. Other common clinical features include ¹³:

• headache

• nausea and vomiting

• seizure

Pathology

Intracerebral haemorrhages arise from rupture of a small blood vessel within the brain parenchyma or, less commonly, of a blood vessel adjacent to the parenchyma (e.g. jet haematoma).

Aetiology

Non-traumatic intracerebral haemorrhages were historically aetiologically divided according to whether or not they have an underlying structural lesion or bleeding diathesis.

1. spontaneous intracerebral haemorrhage presumed due to small vessel disease (formerly primary intracerebral haemorrhage ¹⁰)

   • hypertensive microangiopathy

   • cerebral amyloid angiopathy

2. secondary intracerebral haemorrhage: haemorrhage complicating some underlying structural lesion or bleeding diathesis

   • haemorrhagic transformation of infarct (ischaemic stroke)

   • vascular malformation (e.g., brain arteriovenous malformation, cerebral cavernous malformation)

   • tumour (e.g., metastases, glioblastoma)

   • cerebral venous thrombosis

   • bleeding diathesis (e.g., anticoagulation therapy)

Location

Non-traumatic intracerebral haemorrhages are classified by location, which vary by aetiologic association ⁹.

• lobar intracerebral haemorrhage: in any lobe(s) of the cerebral hemispheres in a cortical and/or subcortical location (excluding deep hemispheric and infratentorial regions)

• non-lobar intracerebral haemorrhage: in deep hemispheric or infratentorial location

  • deep hemispheric (basal ganglia, thalamus, internal capsule)

  • brainstem (pons, midbrain, medulla)

  • cerebellum

Radiographic features

CT

CT is usually the modality first obtained and demonstrates a hyperdense collection of blood, often with surrounding hypodense oedema. A number of complications may be present, such as extension of the haemorrhage into other intracranial compartments, hydrocephalus, herniation, etc.

A number of CT features can predict the likelihood of haemorrhage expansion and are therefore useful in decision-making and prognosis.

• non-contrast CT

  • haemorrhage size

    • the volume of an intracerebral haemorrhage can be measured using ABC/2 formula or 3D volumetric software

    • haemorrhage size is considered to be the most reliable independent predictor of ICH expansion

    • haematoma expansion is measured as an increased growth >12.5 mL or volume >33% from the initial CT scan

    • haematomas with a volume of more than 30 mL are more prone to expansion

  • haemorrhage shape

    • intracerebral haemorrhage irregularity is thought to be due to multiple leaking vessels feeding the haematoma

    • haemorrhages with irregular shapes are more prone to expansion

  • haemorrhage density

    • the presence of hypodense or isodense regions within the hyperdense intracerebral haemorrhage represents active bleeding and is called swirl sign

    • when the swirl sign is encapsulated it is termed black hole sign

    • the presence of a relatively hypodense area adjacent to a hyperdense area is termed the blend sign

    • heterogeneous haemorrhage with hypodense foci is more prone to expansion

  • intraventricular haemorrhagic extension​

    • intraventricular haemorrhagic extension occurs due to decompression of the haemorrhage into the low resistance ventricular system, thus; haematomas located in the thalamus, caudate nucleus or pons are more prone to intraventricular extension than lobar haematomas

    • a study has shown that lenticular and lobar haematomas with accompanying intraventricular extension displayed a higher proportion of haematoma expansion ⁵​

• contrast-enhanced CT

  • active contrast extravasation within haematoma predicts future haemorrhage expansion, this can be observed on CT angiography (CTA) as spot sign and pooling of contrast within the haematoma

MRI

Findings depend on the size and age of the bleed (see ageing blood on MRI). MRI may also reveal clues to the aetiology, such as those of cerebral small vessel diseases (e.g. hypertensive microangiopathy, cerebral amyloid angiopathy).

Treatment and prognosis

Management is time-critical ^14,15, with the principles of management including ¹²:

• control of blood pressure, aiming for a systolic blood pressure of ~140 mmHg

• reversal of any anticoagulation or coagulopathy

  • there is a paucity of evidence to support the effectiveness of routine use of haemostatic agents

• management of raised intracranial pressure

  • e.g. external ventricular drain in the acute setting (especially if there is concurrent intraventricular haemorrhage), decompressive hemicraniectomy

• neurosurgical haematoma evacuation can be considered on a case-by-case basis

  • more evidence to support neurosurgical intervention in posterior fossa intracerebral haemorrhage, and minimally invasive evacuation techniques in lobar intracerebral haemorrhage ¹⁶

  • e.g. minimally invasive techniques, craniotomy

• management of seizures with antiseizure medications

  • there is a paucity of evidence to support the effectiveness of antiseizure medication prophylaxis for patients without seizures

Additionally, supportive care should be provided, including caring for patients in dedicated inpatient stroke units and attempting to prevent the numerous complications which are encountered by patients with neurological impairment from stroke.

Practical points

With any intracerebral haemorrhage the following points should be included in a report as they have prognostic implications ³:

• location

• size/volume

  • the ABC/2 formula is widely used, but there may be more accurate formulas (e.g. 2.5ABC/6, SH/2) and analyses available, some of which, however, may require the addition of specific software to the standard PACS tools

• shape (irregular vs regular)

• density (homogeneous vs heterogeneous)

• presence/absence of substantial surrounding oedema that may indicate an underlying tumour

• presence/absence of intraventricular haemorrhage

• presence/absence of hydrocephalus

• when CT angiography is performed, the presence/absence of the CTA spot sign or a vascular malformation

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