Lobar intracerebral hemorrhage

Last revised by Rohit Sharma on 11 Apr 2024

Lobar intracerebral hemorrhage is a subtype of intracerebral hemorrhage defined by their location in the peripheral cerebral hemispheres. Compared to deep intracerebral hemorrhages (involving the deep grey nuclei or brainstem), lobar hemorrhages are less likely to be related to hypertension and more likely to be due to cerebral amyloid angiopathy or trauma. This article concerns spontaneous (non-traumatic) lobar intracerebral hemorrhages.

Primary lobar hemorrhage accounts for approximately 3.9% of acute strokes and 35% of intracerebral hemorrhages 1.

Cerebral amyloid angiopathy is a major risk factor for lobar hemorrhage, with estimates that over 20% of lobar hemorrhages were due to cerebral amyloid angiopathy (majority of which are seen in elderly patients). Hypertension, diabetes, smoking, short stature, dyslipidemia, and anticoagulant use are also significantly associated with primary intracerebral hemorrhage.

Younger patients may also develop lobar hemorrhages, but in such cases there is usually an underlying lesion (e.g. cerebral arteriovenous malformation2,8.

Clinical presentation will vary depending on the site and size of the hemorrhage. Potential clinical features include 16:

  • headache and vomiting are the most common symptoms at initial presentation

  • focal neurological deficits

  • seizure can also occur during the onset of the lobar hemorrhage (focal or generalized with a brief duration)

  • delirium is increasingly being recognized as a common finding and can be the initial presenting illness

  • decreased conscious state

Often the cause of a lobar hemorrhage is never established and the causes, when found, are varied including 9,10:

One of the strongest predictors of an underlying vascular lesion is the patient's age 11. The younger a patient, the more likely there is an identifiable cause: CT angiography found causes for hemorrhage in 47% of patients aged 18-45 years, 15% aged 46-70 years, and 4% aged 71-94 11.

Overall features of the hemorrhage that suggest an underlying secondary cause are 12:

CT is usually the modality first obtained when evaluating a suspected lobar hemorrhage. Noncontrast enhanced CT typically demonstrates a hyperdense collection of blood, located superficially within the lobes of the brain (i.e. not in the basal ganglia).

The hemorrhages can vary in size from only a centimeter or so (often asymptomatic) to larger hematomas where there may be extension into subdural, subarachnoid and even the intraventricular space (intraventricular extension being more common in basal ganglia hemorrhages). The ABC/2 formula gives reliable estimation of the intracerebral hematoma volume.

There are many predictors of hematoma expansion potentially evident on CT, which are discussed in depth in the main intracerebral hemorrhage article.

CTA is increasingly being used in the initial workup, not only to assess for an underlying abnormality such as arteriovenous malformations, vasospasm, and aneurysmal disease, but also to evaluate for the presence of ongoing bleed.

The CTA spot sign, characterized by a defined "spot" or foci, is a radiographic sign indicative of ongoing bleeding. The presence of the spot sign correlates with growth of the hemorrhage in the first few hours following the scan and is associated with a poorer prognosis 2,3

The presence of the spot sign on dynamic-enhancement CT (DECT or CT perfusion) may be an even stronger predictor of hematoma expansion 4,5, i.e. the most robust factor in predicting outcome 8.

MRI is usually obtained when concern exists that the bleed is from an underlying vascular malformation or neoplasm. Findings depend on the size and age of the bleed (see aging blood on MRI). 

In cases of primary lobar hemorrhage, multiple small areas of susceptibility-induced signal drop-out may be evident on gradient echo (GRE) or susceptibility weighted (SWI) sequences, in-keeping with previous cerebral microhemorrhages, suggestive of cerebral amyloid angiopathy.

The presence of single lobar hemorrhage is still part of the Boston criteria for CAA.

Overall, management does not differ for other causes of intracerebral hemorrhage - please see the article on intracerebral hemorrhage for further discussion 15.

Notably, neurosurgical intervention currently has mixed evidence in patients with lobar intracerebral hemorrhage. One randomized trial (STICH II) suggested early surgical therapy did not decrease the rate of death or disability at six months 13. However, another randomized control trial (ENRICH) showed that minimally invasive hematoma evacuation, within 24 hours of presentation, improved functional outcomes 17.

The term lobar hemorrhage is often used to denote a primary hemorrhage. As such the differential includes:

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