We report a 58-year-old woman with longstanding migraine who developed
a pattern of weekend headaches which occurred only while staying at h
er Connecticut vacation home. The headaches promptly responded to suma
triptan. Investigation revealed it high carbon monoxide level in her h
ome due to a defective furnace. Replacing the furnace eliminated the h
eadaches. This case highlights the importance of searching for seconda
ry causes of headache even in patients responsive to sumatripten. It a
lso suggests that carbon monoxide may trigger headaches mediated by tr
igeminovascular inflammation.