Reversible cerebral vasoconstriction syndrome developing after an erenumab injection for migraine prevention

Background: Reversible cerebral vasoconstriction syndrome is normally triggered by vasoactive compounds or illicit drugs. A new type of migraine preventive medication blocks calcitonin gene-related peptide utilizing monoclonal antibodies. Calcitonin gene-related peptide is a potent vasodilator for the cerebrovascular system. Could blocking calcitonin gene-related peptide be a trigger for cerebral artery vasospasm in patients susceptible to developing reversible cerebral vasoconstriction syndrome (migraine patients) or in individuals using vasoactive compounds? We present a case of reversible cerebral vasoconstriction syndrome occurring after calcitonin gene-related peptide monoclonal antibody treatment. Case report: A 43-year -old woman with a history of episodic migraine developed an acute headache with orgasm two days after taking her second injection of erenumab. Ten days after erenumab injection she developed a thunderclap headache while completing a high intensity workout. These new headaches were only left sided. Computed tomography angiography demonstrated mild to moderate areas of narrowing involving the left middle and anterior cerebral arteries, concerning for reversible cerebral vasoconstriction syndrome. She denied exposure to any known reversible cerebral vasoconstriction syndrome precipitant medication or illicit drugs. She did endorse recent exposure to high altitude prior to erenumab therapy. She was started on verapamil 40 mg three times per day and her headache ceased within 24 h of initiating treatment. A repeat CT angiogram completed 4 weeks after the initial study noted resolution of the areas of vessel stenosis. Conclusion: A case of reversible cerebral vasoconstriction syndrome developing after treatment with a calcitonin gene-related peptide monoclonal antibody is presented. The timing of the new type of headache occurring 2 days post erenumab injection suggests a possible cause and effect relationship. Reversible cerebral vasoconstriction syndrome as a possible treatment-related complication to the usage of calcitonin gene-related peptide monoclonal antibodies needs to be studied further.