Treatment options for large hemispheric stroke.

Some stroke patients suffering acute middle cerebral artery (MCA) infarction develop massive brain edema and herniation, a condition known as malignant MCA infarction. Severe swelling increases intracranial pressure (ICP) and leads to progressive brainstem dysfunction. Once ICP reaches critical values (>30 mm Hg) herniation occurs, usually within 2 to 5 days. Patients rarely survive (80% mortality) with standard treatment, and those who do are often severely disabled. Malignant MCA infarction is often missed by neurologists, despite well-defined clinical and neuroimaging (CT scan) diagnostic criteria. After diagnosis, conventional treatments such as osmotherapy, barbiturates, buffers, and hyperventilation center on reducing ICP. The goal of hyperosmolar therapy is to increase the serum osmolarity to approximately 315-320 mOsm/L. Enteric glycerol is used routinely to reduce ICP. In more severe cases and when glycerol fails, mannitol may be administered. Other therapies are also available, including hypertonic saline solution, THAM (Tris-hydroxy-methyl-aminomethane) buffer, and high-dose barbiturates. Hyperventilation also helps reduce ICP. All measures work effectively for a short time only. Other approaches to control elevated ICP, including decompression surgery and hypothermia, have shown promising results. In the Heidelberg decompression surgery trial, mortality in surgically treated patients was significantly lower (32%) than in non-treated patients (76%) despite conventional treatment. Importantly, of the surviving treated patients, 66% were rated independent with only mild to moderate disability. Moderate hypothermia (33-36 degrees C) has recently been shown to be effective in severe MCA infarction. Hypothermia induction within 14 hours of ischemic injury and maintained for 72 hours significantly reduced ICP and mortality (44%).