Prolonged undiagnosed fever in northern India.

A prospective study for five years along with a retrospective analysis of all patients admitted over 10 years with the diagnosis of prolonged undiagnosed fever was carried out in a referral hospital of North India to determine the specific disorders responsible for it. One hundred and fifty patients (80 prospective and 70 retrospective) were included in the study. Infections, especially tuberculosis, was the most dominant cause (50%), followed by lymphoreticular and haematological disorders (21.32%), collagen vascular disorders and neoplasms (8.67%) each. Miscellaneous causes were responsible in 6.67% and in 4.67% the cause of fever remained undiagnosed.