Urgent Neuroimaging for Secondary Headache Disorders

Red Flags Demanding Urgent Evaluation

Positional headache worse when lying down suggests increased intracranial pressure from mass lesion, venous sinus thrombosis, or other space-occupying pathology, according to the American Academy of Family Physicians and the American Academy of Neurology 1, 2
Failure to respond to acetaminophen, ibuprofen, and rimegepant indicates this is unlikely to be primary migraine, as these represent different therapeutic mechanisms that should provide at least partial relief in true migraine, as stated by the American College of Physicians 3
Unilateral frontal-to-occipital distribution can represent vascular pathology or structural lesions, as noted by the American Academy of Family Physicians and the American Academy of Neurology 1, 2
The American Academy of Family Physicians recommends considering neuroimaging in patients with headache worsened by Valsalva's maneuver or atypical features that do not meet strict migraine criteria 1

Venous sinus thrombosis presents with positional headache worse when lying down, nausea, and can mimic migraine, according to the American Academy of Neurology 2
Intracranial mass or tumor causes positional headache from increased intracranial pressure, as stated by the American Academy of Family Physicians and the American Academy of Neurology 1, 2
Spontaneous intracranial hypotension, though typically better when lying down, can have atypical presentations, as noted by the American Academy of Neurology 2

The American Academy of Family Physicians and the American Academy of Neurology recommend obtaining urgent neuroimaging, such as CT head without contrast as initial screen, and MRI brain with venography if CT negative but suspicion remains high 1, 2
The American College of Physicians suggests providing symptomatic relief with IV therapy, including metoclopramide 10 mg IV for nausea and direct analgesic effects, and ketorolac 30 mg IV for pain, if no contraindications 3

The American Academy of Neurology notes that the pattern of positional worsening when lying down is fundamentally inconsistent with typical migraine, which usually improves with rest in a dark, quiet room 2
The American College of Physicians states that failure of rimegepant suggests the headache mechanism is not primarily driven by CGRP-mediated neurogenic inflammation typical of migraine 3
The American Academy of Family Physicians and the American Academy of Neurology warn that treating presumed migraine without imaging in the presence of red flags can delay diagnosis of life-threatening conditions and lead to catastrophic outcomes 1, 2