A rare cause of symptomatic cluster headache

Cluster headache (CH) is characterized by recurrent attacks of short-lasting excruciating pain accompanied by signs of autonomic dysfunction. Although neuroimaging results are usually normal in primary headaches, rarely structural lesions may be associated with CH like presentation. Most symptomatic CH is due to pituitary tumors and less commonly due to arteriovenous malformations (AVM) and aneurysms. Here we describe a case of 44-year-old male who presented to us with new onset episodic CH with headache features typical. Initially, headache responded to treatment, but later the headache became continuous, severe in intensity and refractory to treatment. Since magnetic resonance imaging was normal, he was subjected to digital substraction angiography (DSA) to rule out aneurysm or AVM. DSA revealed indirect carotid-cavernous fistula (CCF). Once the fistula was obliterated with onyx embolization, headache subsided completely. MRI brain is often routinely performed in CH to rule out secondary causes. When MRI brain is normal, detailed vascular imaging with DSA must be performed in patients with CH with especially in those with atypical features. Like continuous pain refractory to treatment, sudden increase in severity in the first episode, minimal or absent autonomic features and abnormal physical findings like persistent ptosis in the headache-free period. Although many cases of symptomatic CH have been reported in literature we report the first case of CCF presenting as CH. Early identification is essential as it is completely curable with endovascular treatment