[Verified Answer]: A nurse practitioner is evaluating four…

A nurse practitioner is evaluating four adult patients presenting with different types of headache. Based on current evidence and clinical red flag criteria, which of the following patient scenarios most urgently requires referral to a specialist or emergency department for further evaluation? A patient with a tension-type headache triggered by stress, described as mild, bilateral pressure without nausea or vomiting. A patient with a first-onset cluster-type headache: severe unilateral orbital pain, ipsilateral conjunctival injection, and nasal congestion. A patient with episodic migraine without aura, reporting throbbing pain, nausea, and photophobia that resolves with rest. A patient with chronic migraine, experiencing more than 15 headache days per month, including menstrual-related migraines.