Headache caused by lymphocytic hypophysitis, associated with pituitary enlargement and, in half of cases, with hyperprolactinaemia. It remits after successful treatment of the lymphocytic hypophysitis.
A. Any headache fulfilling criterion C
B. Lymphocytic hypophysitis has been diagnosed
C. Evidence of causation demonstrated by either or both of the following:
1. headache has developed in temporal relation to the onset of the lymphocytic hypophysitis
2. either or both of the following:
a) headache has significantly worsened in parallel with worsening of the lymphocytic hypophysitis
b) headache has significantly improved in parallel with improvement in the lymphocytic hypophysitis
D. Not better accounted for by another ICHD-3 diagnosis.
Lymphocytic hypophysitis is associated with pituitary enlargement and homogeneous contrast enhancement on brain MRI. It is accompanied by hyperprolactinaemia in 50% of cases or autoantibodies against hypophyseal cytosol protein in 20% of cases.
The disorder typically develops at the end of pregnancy or during the post-partum period, but it can also occur in men.