Differential Diagnosis, Including Secondary Forms

Abstract

Cluster headache is one of the trigeminal autonomic cephalalgias (TACs). These are primary headache syndromes that share some clinical features, such as a trigeminal distribution of the pain, which is ipsilateral and usually side-locked, and accompanying ipsilateral autonomic symptoms. By definition, no underlying structural lesion for the headache is found. There are, however, many descriptions in the literature of patients with structural lesions causing symptoms that are indistinguishable from those of idiopathic TACs. In this chapter, we are going to give an overview of the different primary, and secondary, forms of cluster headache and the other TACs, in order to provide some guidance of the differential diagnoses that should be considered, and the diagnostic investigations that should be done, when one encounters a patient who appears to be suffering from cluster headache, or one of the other TACs, or even a TAC-like syndrome.