A 65-year-old man comes to the emergency department an hour after acute-onset, right-sided weakness and numbness. Symptoms progressed over several minutes, and the patient is now experiencing nausea and headache. He has smoked half a pack of cigarettes per day for 32 years. Physical examination shows 3/5 muscle strength and hyperreflexia in the right upper and lower extremities. Sensation to pinprick and light touch is decreased on the right side. He has mild dysarthria. Noncontrast CT scan is of the head shown in the image below:
Show Explanatory Sources
Which of the following is the most likely underlying cause of these findings?
Patterns of intracranial hemorrhage by location | |
Intraparenchymal hemorrhage |
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Subarachnoid hemorrhage |
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AVM = arteriovenous malformation; CAA = cerebral amyloid angiopathy; SAH = subarachnoid hemorrhage. | |
This patient has an acute left basal ganglia (putaminal) hemorrhage. Intraparenchymal (brain) hemorrhages (IPHs) typically present with sudden focal neurologic deficits that gradually worsen over minutes to hours. As the hemorrhage expands, headache, nausea/vomiting, and altered mental status can develop due to elevated intracranial pressure. Putaminal hemorrhage almost always involves the adjacent internal capsule, leading to contralateral hemiparesis and hemianesthesia due to disruption of the corticospinal and somatosensory fibers in the posterior limb.
The location of the IPH can suggest the etiology. The most common cause of spontaneous IPH impacting the basal ganglia is hypertensive vasculopathy involving the small penetrating branches of the major cerebral arteries. The basal ganglia are supplied by the lenticulostriate arteries (small-vessel branches from the middle cerebral artery). Other common regions of hypertensive bleed include the cerebellum, thalamus, and pons. Bleeding usually results from the rupture of hypertension-induced Charcot-Bouchard aneurysms.
(Choice A) Cerebral amyloid angiopathy (CAA) is the most common cause of spontaneous lobar/cortical hemorrhage (eg, occipital, parietal) in individuals age >60. A subcortical location, as seen in this patient, is not typical of CAA.
(Choice B) Hemorrhagic transformation of ischemic stroke occurs when blood extravasates from injured cerebral vessels into the brain parenchyma. Clinically, patients have signs, symptoms, and CT scans consistent with ischemic stroke, then have an abrupt worsening of neurologic symptoms several hours to a few days later. If the CT scan is delayed, it may have a similar appearance, but the scan obtained an hour after symptom onset shows a hyperintensity more consistent with spontaneous ICH.
(Choice D) High-pressure blood flow through weak-walled veins in arteriovenous malformations (AVMs) can lead to rupture. These present in people age 10-40 (most commonly in childhood) and can be intraparenchymal or subarachnoid depending on the location of the AVM. However, AVMs are quite uncommon compared to hypertensive bleeding, especially given this patient's age.
(Choice E) Ruptured berry aneurysms cause subarachnoid hemorrhage (vs this patient's IPH), which is characterized by the abrupt onset of severe (thunderclap) headache and hyperattenuation of the sulci and basal cisterns on CT scan of the head.
Educational objective:
The most common cause of spontaneous hypertensive intraparenchymal hemorrhage impacting the basal ganglia is hypertensive vasculopathy. It can also lead to hemorrhagic stroke involving the cerebellar nuclei, thalamus, and pons.