Abstract

Introduction

Background-Although earliest fever curves was created in 10^th century by Akhawayni, fever was reported by Beeson (1961) as the presence of an endogenous pyrogen in rabbit PMNL. Today the granulocyte factor is the central role in pathogenesis of fever. Normal body temp is 98.6*f and fever is a complex physiological response involving the innate immune system and any temperature beyond the normal. Hippocrates and Kos (377BCE) attributed to pyretos and therme (fever and heat) which arose from 4 elements-blood, phlegm, black bile and yellow bile. Farenheit and Celsius were pioneers in development of thermometer and axillary temperatures were first used for fever Then Mackowiak and collegues described an oral thermometer and they gave 98.6*f as normal and 99.9*f as upper limit of normal. Thermoregulatory behaviours (brown adipose tissue thermogenesis, shivering, sweating, vasoconstriction and vasodilation) are the control loops in response to core and skin temperature.

Of the illnesses, infection, neoplasia, inflammatory, miscellaneous and undiagnosed illness form the main group. In India, infections constitute 16-55% of cases. Now in industrialized countries, undiagnosed cases have risen. Among the infections, UTI, TB, viral and protozoal abcess, endocarditis are frequently diagnosed out of which viral infections predominate. In older patients infections are less frequent cause of fever which is opposite to pediatric population. Travel history and vaccination history is important as in COVID era. Lab findings were consistant with clinical presentation in 90% of cases .Mortality out of fever was very negligible only in older patients (1-3%).