Eight years of investigation failed to disclose the nature of recurrent five-day episodes of fever in an otherwise healthy man. Although graphic records of the temperature kept by the patient showed episodes at intervals of about every 21 days at first, lengthening to about 63 days at present, 15 physicians did not consider periodic fever as a diagnosis among 14 other diseases. When better known diseases are excluded, recognition of periodic fever obviates continued unnecessary diagnostic effort and expense. The cause is unknown, and treatment is ineffective.
(JAMA 228:1662-1664, 1974)