An approach to identifying isolated intraventricular hemorrhages on brain computed tomography (CT)
Intraventricular hemorrhages frequently occur in patients with traumatic and parenchymal hemorrhages. But, isolated ventricular hemorrhages without a history of trauma and without subarachnoid or parenchymal hemorrhaging are rare.
Let’s explore several cases where intraventricular hemorrhaging occurred without a history of trauma. We’ll consider what to look for on computed tomography (CT), as well as additional testing that can be used to determine the cause of hemorrhaging for each patient case. Keep in mind that pure intraventricular hemorrhaging (without evidence of excessive anticoagulation) warrants further evaluation to determine the source of hemorrhaging!
Five common non-traumatic causes of intraventricular hemorrhage include:
- Ruptured saccular aneurysm
- Arteriovenous malformation
- Cavernous angioma
- Elevated international normalized ratio (INR)
- Moyamoya disease
Intraventricular hemorrhage case 1: Ruptured saccular aneurysm
In our first case, intraventricular high attenuation blood was associated with a parenchymal hemorrhage on the same side. To determine the source of the hemorrhages, a digital subtraction angiography (DSA) was ordered.
The source of the parenchymal hemorrhage was a ruptured saccular aneurysm arising at the origin of the posterior cerebral artery (PCA). While it is not typical for an aneurysm to present with a parenchymal hemorrhage and without a subarachnoid hemorrhage, this case illustrates the intraventricular hemorrhage extending from a parenchymal brain hemorrhage.
Intraventricular hemorrhage case 2: Arteriovenous malformation
In our next case, a 22-year-old patient presented with a sudden onset of severe headaches. Her CT scan demonstrated high attenuation within the right and left ventricles with no evidence of any nearby brain abnormalities. Based on the age of the patient and the absence of any history of anticoagulation, a cerebral DSA was performed to look for a vascular cause of the bleeding.
Her DSA demonstrated an arteriovenous malformation (AVM); note the diffuse nidus of the AVM and the early draining vein (Fig. 2).
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Intraventricular hemorrhage case 3: Cavernous angioma
The CT scan of a 40-year-old man demonstrated an extensive intraventricular hemorrhage which appeared to expand the fourth ventricle and extend into the foramina of Luschka. There was no history of trauma or other potential causes of bleeding.
A DSA was performed since an aneurysm arising from the posterior inferior cerebellar artery (PICA), AVM, or dural fistula were all possible diagnoses at the time.
The DSA was normal in this patient, but because the source of the bleeding remained unexplained, a magnetic resonance imaging (MRI) scan of the brain and cervical spine was ordered.
The MRI demonstrated a mass with a dark rim next to the ventricle. This proved to be a cavernous angioma, also known as a cavernoma, during surgery. This is a benign vascular malformation that usually causes a parenchymal hemorrhage—but can also bleed into the ventricle or subarachnoid space (depending on its location).
Intraventricular hemorrhage case 4: Elevated international normalized ratio (INR)
A 72-year-old patient presented with headaches, an unsteady gait, and a diminished level of consciousness. His CT scan demonstrated a cerebrospinal fluid (CSF)-blood level (a visible line at the interface between the CSF and blood) in the atrium of the left ventricle. Remember, that due to gravity, blood will settle to the lowest part of the ventricle.
The patient’s lab studies in the emergency room revealed an international normalized ratio (INR) of 8.0 when the normal at this hospital is below 1.2. This was most likely due to his treatment with warfarin for atrial fibrillation but with poorly controlled drug levels.
Nevertheless, a computed tomography angiography (CTA) was performed but proved to be negative. The greatest likelihood was that the patient’s elevated INR was the cause of the hemorrhage.
Intraventricular hemorrhage case 5: Moyamoya disease
A 42-year-old patient’s CT scan showed intraventricular blood with no history of anticoagulation medications or trauma.
A CTA revealed an unusually small right middle cerebral artery (MCA) that was substantially smaller than the left middle cerebral artery. A DSA was ordered.
The patient’s DSA revealed an abnormal cluster of collateral vessels near the distal carotid. This proved to be the result of longstanding stenosis of the proximal middle cerebral artery.
These enlarged vessels provide blood supply to portions of the brain that would otherwise have insufficient blood flow. The sudden filling of these collaterals on DSA accounts for the name of this disease, moyamoya. The word means puff of smoke in Japanese and describes the vascular blush of these enlarged collateral vessels. In adults, moyamoya disease can be the cause of hemorrhages and was likely the explanation for the patient’s intraventricular hemorrhage.
So, we’ve covered several possible scenarios such as a ruptured saccular aneurysm, an arteriovenous malformation (AVM), a cavernous angioma, and moyamoya disease. Keep these in mind as you search for the cause of an isolated intraventricular hemorrhage. When you encounter a patient with an isolated nontraumatic intraventricular hemorrhage (and a normal INR), consider additional imaging since it’s likely that there is an underlying vascular abnormality.
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