It is the summer season, and patients with signs and symptoms of heat-related illness present in the emergency department. Which patient needs attention first?

A homeless person, poor historian, presents with altered mental status, poor muscle coordination, and hot, dry, ashen skin.

A previously healthy homemaker reports broken air conditioner for days; tachypnea, hypotension, fatigue, and profuse diaphoresis are observed.

A marathon runner complains of severe leg cramps and nausea; tachycardia, diaphoresis, pallor, and weakness are observed.

An elderly person complains of dizziness and syncope after standing in the sun for several hours to view a parade.