Heart appearance sign in pontine stroke: a result of bilateral infarction due to small vessel disease

Acute Onset Quadriplegia and Stroke: Look at the Brainstem, Look at the Midline

Acute onset quadriplegia with or without facial sparing is an extremely rare vascular syndrome, and the main focus of attention is on the cervical and upper thoracic spinal cord as the putative site of the damage. Quadriplegia has been occasionally reported in brainstem strokes within well-defined lesion patterns, but these reports have gained little attention so far because of the rarity of this clinical syndrome. The clinical, neuroanatomical and neuroimaging features of ischemic stroke locations associated with quadriplegia have been collected and reviewed in a pragmatical view, which includes a detailed description of the neurological signs associated with the damage of the pyramidal pathways. Two clinical examples have been added to raise practical suggestions in neurovascular practice. Ischemic stroke sites determining quadriplegia have some main well-defined midline locations in the brainstem, involving the pyramidal pathways of both sides in a single synchronous ischemic lesion in the medulla oblongata and in the pons. Several accompanying neurological signs have been described when the ischemic lesion involves tracts and nuclei other than the pyramidal pathways, and they can be useful as localizing clues. In some cases, the typical neuroimaging appearance of the ischemic lesion on Magnetic Resonance Imaging (MRI) has been reported as being a "heart appearance sign". This last sign has been described in midbrain strokes too, but this location is not associated with quadriplegia. The main etiology is atherothrombosis involving the intradural segment of the vertebral artery (VA) and their perforating branches. Two clinical examples of these rare vascular syndromes have been chosen to support a pragmatical discussion about the management of these cases. A midline ischemic stroke in the brainstem is a very rare vascular syndrome, and the acute onset quadriplegia is a distinctive feature of it. The awareness of this cerebrovascular manifestation might help to recognize and treat these patients.

The "heart appearance" sign in bilateral pontine infarction

BACKGROUND

Although rarely seen, bilateral anteromedial infarction of the pons demonstrates the characteristic "heart appearance" sign on magnetic resonance imaging (MRI). This sign has hitherto been described in only 2 patients before this article. This typical pattern can be attributed to atherosclerotic or thrombotic involvement of bilateral paramedian and short circumferential pontine arteries supplying the anteromedial pons.

METHODS AND RESULTS

A 60-year-old man, a known patient of primary hypertension and diabetes mellitus, presented with a posterior circulation stroke. Urgent computerized tomography and MRI revealed a "heart-shaped" area of acute infarction in the anteromedian mid-pons. A few scattered infarcts were also noted in the posterior and inferior part of the right cerebellar hemisphere. The basilar artery appeared normal with preserved flow void on MRI, and there were no signs of hemorrhage. These findings were consistent with acute nonhemorrhagic infarcts involving bilateral paramedian and short circumferential pontine arteries and the right posterior inferior cerebellar artery. A repeat MRI performed after a week disclosed hemorrhagic transformation and enhancement of the pontine infarction. The basilar artery appeared normal on magnetic resonance angiography.

CONCLUSIONS

Recognizing the "heart appearance" sign in a stroke-like episode may be helpful in differentiating bilateral anteromedial pontine infarction from other pathologic processes involving the pons.