[Symptomatic headache. Essential differential diagnosis].

A patient is suspected of suffering from a potentially life threatening headache according to the following typical warning signs: sudden onset headache, worst headache, neurological findings, fever, neck stiffness, epileptic seizures and deterioration of vigilance. It is far more dangerous not to recognize potentially life threatening headaches like subarachnoid bleeding, meningitis, encephalitis, arterial dissection or epidural hematoma than to over diagnose it. Immediate and specific neurological and radiological investigations (CT, MRI, CSF) are necessary in each patient presenting with those findings. The morbidity and mortality of those patients mainly depend on the beginning of the therapy. This article focuses on the diagnosis of potentially life threatening headache disorders.