Table 10.2-4. Alarming features (red flags) in a patient with headache


Most frequent causes

Recommended diagnostic studies

Sudden-onset headache (± signs of meningeal irritation)

Subarachnoid hemorrhage, bleeding from tumor or arteriovenous malformation, brain tumor (particularly in posterior fossa)

Neuroimaging,a CSF analysisb

Headache of constantly increasing severity

Brain tumor, subdural hematoma, medication overuse


Headache with accompanying systemic symptoms (fever, nuchal rigidity, rash)

Meningitis, encephalitis, Lyme neuroborreliosis, systemic infection, connective tissue disease (including systemic vasculitis)

Neuroimaging,a CSF analysis,b blood tests as needed

Focal neurologic signs or symptoms, or symptoms other than typical visual or sensory aura

Brain tumor, arteriovenous malformation, connective tissue disease (including systemic vasculitis)

Neuroimaging,a diagnostic workup for connective tissue diseases with vascular involvement


Brain tumor, idiopathic intracranial hypertension, encephalitis, meningitis

Neuroimaging,a CSF analysisb

Headache on coughing, exercise, or Valsalva maneuver

Subarachnoid hemorrhage, brain tumor (particularly in posterior fossa)

Neuroimaginga; consider CSF analysisb

Headache during pregnancy or in postpartum period

Cerebral vein or sinus thrombosis, carotid artery dissection, pituitary apoplexy


New-onset headache in patient with cancer

Cancer metastasis

Neuroimaging,a CSF analysisb

a Computed tomography or magnetic resonance imaging.

b After a mass lesion causing raised intracranial pressure has been excluded by neuroimaging.

CSF, cerebrospinal fluid.