Michael Eller; Peter J Goadsby


Expert Rev Neurother. 2013;13(3):263-273. 

In This Article

Red Flags

An abnormal physical examination in association with headache should prompt appropriate imaging. For example, bilateral papilledema in an overweight woman in her 20s should lead to an MRI brain scan and magnetic resonance venography with contrast, to exclude a mass lesion and intracranial hypertension secondary to venous thrombosis. Scanning can also help confirm the clinical suspicion of idiopathic intracranial hypertension, even in the absence of other associated signs and symptoms, with supportive radiological signs such as posterior globe flattening.[48]

Other concerning features relate to the phenomenology of headache; these 'red flags' are listed in Box 1, and can help stratify the risk of a secondary cause. They incorporate headache intensity and tempo in comparison with the patient at baseline, as well as symptoms of altered intracranial pressure and CNS dysfunction. Abnormal physical findings are also included. There is a variable evidence base for the use of red flags to triage or even mandate imaging in headache. Their utility has been inferred from knowledge of secondary causes of headache; their use in clinical practice is supported by current guidelines.[9,37,101,102]

An autopsy series also supports their use;[49] over a 10-year period a neuropathology unit looked at a proportion of patients that had presented initially with headache. Over 50% of the patients were over 50 years of age. The most common associated symptoms included: seizure, collapse and loss of consciousness (53%), thunderclap headache (51%), worst headache (25%), and nausea and vomiting (17%), among others. Most patients died of vascular events, while a proportion were found to have a tumor or meningitis, among other diagnoses. The authors use the most pertinent red-flag symptoms as a framework below, to briefly discuss the common headache syndromes in which imaging is indicated and often diagnostic.