Final answer:
An NIHSS total score of 16 or more indicates a severe stroke. Early treatment is crucial for potentially salvageable brain regions in the ischemic penumbra.
Step-by-step explanation:
An NIHSS total score of 16 and more than 16 is indicative of a severe stroke. Strokes are a leading cause of death and disability, and they can be categorized into ischemic and hemorrhagic strokes. Ischemic strokes, which are the most common, result from blockages in cerebral blood vessels, often in the middle and anterior arteries, or from general hypo-perfusion, leading to reduced blood flow to the brain and consequently decreased ATP production. The ischemic core is the region with irreversible damage, but the surrounding ischemic penumbra contains tissue that is potentially salvageable. Rapid medical intervention, as with the administration of recombinant tissue plasminogen activator (rtPA), is critical for the possible rescue of these areas.